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CBSE Biology CBSE for 12th Standard CBSE Question paper & Study Materials

CBSE 12th Standard Biology Subject Microbes in Human Welfare Value Based Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    During morning walk one day, Hemant asked his uncle, who was a plant pathologist, that he wanted to control plant pests as these were destroying his garden.But, he did not want to use chemicals due to their long-term harmful effect on the environment.His uncle suggested him to go for biological control methods.
    Read the above passage and answer the following questions:
    (i) What are biopesticides?
    (ii) Name any biological control agent that helps to control mosquito larvae.
    (iii) What value is displayed by Hemant?

  • 2)

    Rahul was not getting a good yield from the fields but his neighbours used to apply fertilizers to get higher yields of different crops.He consulted an agricultural scientist, living in the neighbouring town, to suggest some cheap and eco-friendly method to boost crop production.The scientist suggested him to use biofertilizers.
    (i) What are bio fertilisers?
    (ii) Name two examples of bio fertilisers.
    (iii) Why did scientist advise Rahul to use bio fertilisers?

  • 3)

    Mohan's neighbour suffered from kidney failure and his life was in danger.Doctors advised him to get kidney transplanted immediately.His wife was willing to donate one of her kidneys but she was in dilemma due to low success rate as a result of the immune reaction.She expressed her fear to a doctor who removed her doubts by telling her about the availability of immunosuppressive agents.Read the above passage and answer the following questions:
    (i) What are immunosuppressive agents?
    (ii) Name one immunosuppressive agent and its source.
    (iii) What value is displayed by doctor?

  • 4)

    Protein is an important constituent of our food and its deficiency leads to many health problems.A large population of developing countries can not afford pulses.Ramesh learnt that many so he thought of culturing these microorganisms to provide a cheap source of proteins.
    Read the above passage and answer the following questions:
    (i) What are single cell protein (SCP)?
    (ii) Name two microorganisms which provide SCP.
    (iii) Why did Ramesh want to culture microorganisms?

  • 5)

    During recent years many disease resistant crops plants have been released and many chemical pesticides have also been used to control the pest and diseases, so as to improve the agricultural yield. But such methods of pest and disease management have led to the development of 'super pests and super weeds' which require more scientific methods to control them
    Answer the following questions on the basis of above information:
    (i) Should we continue such a practice of pest and disease management?
    (ii) What other method should be adopted to keep the pest and diseases at managable level so as to enhance the agricultural yield?
    (iii) What value have not been kept in mind in the above case.

CBSE 12th Standard Biology Subject Microbes in Human Welfare Value Based Questions 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    During morning walk one day, Hemant asked his uncle, who was a plant pathologist, that he wanted to control plant pests as these were destroying his garden.But, he did not want to use chemicals due to their long-term harmful effect on the environment.His uncle suggested him to go for biological control methods.
    Read the above passage and answer the following questions:
    (i) What are biopesticides?
    (ii) Name any biological control agent that helps to control mosquito larvae.
    (iii) What value is displayed by Hemant?

  • 2)

    Rahul was not getting a good yield from the fields but his neighbours used to apply fertilizers to get higher yields of different crops.He consulted an agricultural scientist, living in the neighbouring town, to suggest some cheap and eco-friendly method to boost crop production.The scientist suggested him to use biofertilizers.
    (i) What are bio fertilisers?
    (ii) Name two examples of bio fertilisers.
    (iii) Why did scientist advise Rahul to use bio fertilisers?

  • 3)

    Mohan's neighbour suffered from kidney failure and his life was in danger.Doctors advised him to get kidney transplanted immediately.His wife was willing to donate one of her kidneys but she was in dilemma due to low success rate as a result of the immune reaction.She expressed her fear to a doctor who removed her doubts by telling her about the availability of immunosuppressive agents.Read the above passage and answer the following questions:
    (i) What are immunosuppressive agents?
    (ii) Name one immunosuppressive agent and its source.
    (iii) What value is displayed by doctor?

  • 4)

    Protein is an important constituent of our food and its deficiency leads to many health problems.A large population of developing countries can not afford pulses.Ramesh learnt that many so he thought of culturing these microorganisms to provide a cheap source of proteins.
    Read the above passage and answer the following questions:
    (i) What are single cell protein (SCP)?
    (ii) Name two microorganisms which provide SCP.
    (iii) Why did Ramesh want to culture microorganisms?

  • 5)

    A student as a part of his project visited a software company and was surprised to see a sewage treatment plant set up there. He wonders at the role of microbes in one of its steps and specifies it in his project.
    (a)How would he ave described the role of microbes in sewage treat ent plants?
    (b) What would he say was the intention of such a set up?
    (c)What value would he have imbibed from there

CBSE 12th Standard Biology Subject Microbes in Human Welfare Value Based Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Pushpender is a scientist working on GMOs to produce Transgenic Buffaloes which can produce milk of medicinal properties. But he also found adverse effects on which they reduce their life span. Based on this, Answer the following.
    a) What values are being neglected by him?
    b) Should he continue with transgenic production of Buffaloes?
    c) What Reactions and Reflections would he face from various organizations?

  • 2)

    Sandeep is a Biology Student of class xii. He learnt from his teacher that lack of insulin hormone in our body can be injected through syringes. One day his father shows symptoms of Diabetics and he suggested him to meat doctor for Diagnosing Insulin product. On the basis, Answer the following questions.
    a) What did Sandeep understands about insulin?
    b) On what basis did Sandeep advice his father?
    c) Which American based company produced insulin at first and in which year?

  • 3)

    Gel Electrophoresis a Technique used to separate DNA fragments after the function of Endonuclease. Sushi couldn’t understand the actual function of Restriction Endonuclease. He takes the help of his friend sham by asking the questions. On the basis answer the following.
    a) What is the difference between Exonuclease and Endonuclease?
    b) Why sham did help his friend Sushi?
    c) How can we see DNA fragments after the separation?

  • 4)

    In a village Two friend farmers Ramnath and Kishan are cultivating normal cotton saplings. Every year they suffer and get fewer yields and lose money. One day Kishan watches add in television on Bt Cotton and encourages his fellow farmer, they were surprised by seeing high yield. Based on this, answer the following.
    a) What is Bt cotton?
    b) What way Bt kills lepidopteron, coleopterans and dipterans in the soil?
    c) How could the information passed on to the farmers? What is the value that a fellow farmers can learn from this?

  • 5)

    Jevan’s friend’s uncle suffers from reduced body weight loss. He suspects HIV. He wants to diagnose immediately. But due to shy he delays to meet doctor. One day Jevan came to know and advices him to go for ELISA or PCR Test. Based on these answer the following questions?
    a) What are ELISA and PCR?
    b) What makes Jevons uncle feel shy to meet doctor?
    c) What are the steps involved in PCR?

CBSE 12th Standard Biology Subject Microbes in Human Welfare Value Based Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Municipal Corporation has deputed personnel to check for mosquito breeding in your school.
    a) Which are the places they should check for mosquitoes and there larvae?
    b) Name to diseases which are spread by mosquitoes.
    c) Name any two biological agents which can be used to control mosquitoes

  • 2)

    Prabha has seen huge garbage dumps outside your school which are not being regularly disposed of by MCD / Nagar Parishad. Prabha discusses the problems with school mates and decide to organize rally to spread awareness among local people about public hygiene.
    A. Prepare two slogans for rally
    B. Name any two infectious diseases which may spread due to such unhygienic conditionsat public place

  • 3)

    Sandeep is a Biology Student of class xii. He learnt from his teacher that lack of insulin hormone in our body can be injected through syringes. One day his father shows symptoms of Diabetics and he suggested him to meat doctor for Diagnosing Insulin product. On the basis, Answer the following questions.
    a) What did Sandeep understands about insulin?
    b) On what basis did Sandeep advice his father?
    c) Which American based company produced insulin at first and in which year?

  • 4)

    Genes encoding resistance to antibiotics like Ampicillin, chloramphenicol, tetracycline are useful selectable markers for E.coli. The normal E.coli cells do not carry resistance against any of these antibiotics. Ankita wants to know more clarity on these scriptures. She asks doubts to her teacher. Based on this please answer the following.
    a) Name the best known plasmid vector?
    b) What are selectable markers?
    c) On what basis Biology teacher advices Ankita.

  • 5)

    Jevan’s friend’s uncle suffers from reduced body weight loss. He suspects HIV. He wants to diagnose immediately. But due to shy he delays to meet doctor. One day Jevan came to know and advices him to go for ELISA or PCR Test. Based on these answer the following questions?
    a) What are ELISA and PCR?
    b) What makes Jevons uncle feel shy to meet doctor?
    c) What are the steps involved in PCR?

CBSE 12th Standard Biology Subject Environmental Issues Value Based Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    During her tour to a renowned forest, Sakshi saw a highway being constructed, which passes through the middle of the forest. She was unhappy seeing that and on return, she contacted the local eco-club and approached the concerned department to stop the work.
    (i) What would be effect on biodiversity, if the highway is constructed?
    (ii) How forests are useful to mankind?
    (iii) what values of Sakshi reflect here?

  • 2)

    Seeing a crowd of students in one corner of the school, the principal rushed to see the matter and found some children heating and chasing a small lizard. On seeing the principal, all the children fled to their classes except Alok who requested the principal to arrange for some medical assistance for the injured animal. The principal rewarded Alok for his attitude to save guard our biodiversity.
    (i) What do you understand by biodiversity?
    (ii) Mention the factors resulting in loss of biodiversity.
    (iii) Was Alok an indisciplined boy, who did not run to the class on seeing the principal? What values does the acts promote?

  • 3)

    During an excursion to a botanical garden, the teacher shows an old tree, which was on the verge of extinction. As soon as the teacher advanced with students, some enthusiastic students climbed up the tree and started cutting the branches, collecting its leaves as precious collection. Rajesh instead took photographs of the tree from various angles. The boys mocked at Rajesh while the teacher appreciated him
    (i) Why should we conserve biodiversity?
    (ii) How can biodiversity be conserved?
    (iii) What international initiatives were taken to conserve biodiversity?
    (iv) What values did Rajesh possess?

  • 4)

    On his visit to national park, Harshendra, was very angry as the forest authorities did not allow him to enter a specified area.
    On returning back, he discussed the matter with his friend, who explained him the reason.
    (i) Which category of conservation strategy does national park belong?
    (ii) Name India's first national park.
    (iii) At present, there are how many national parks in India?
    (iv) what values are shown by Harshendra's friend?

  • 5)

    Mohan and Sohan established a factory in partnership. It was running all well but after a few months its electrostatic precipitator suddenly got out of order and stopped working. Mohan made up his mind to replace it with the new one but Sohan didn't agree to Mohan's proposal and said that they should not waste money in replacing it because it has no effect on productivity and income. Answer fo owing questions on the basis of above information:
    (i) Out of the two partners whome you will support and why?
    (ii) What measures could you suggest to stop such a negligence?
    (iii) What values are exhibited by Sohan?

CBSE 12th Standard Biology Subject Environmental Issues Value Based Questions 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    During her tour to a renowned forest, Sakshi saw a highway being constructed, which passes through the middle of the forest. She was unhappy seeing that and on return, she contacted the local eco-club and approached the concerned department to stop the work.
    (i) What would be effect on biodiversity, if the highway is constructed?
    (ii) How forests are useful to mankind?
    (iii) what values of Sakshi reflect here?

  • 2)

    Seeing a crowd of students in one corner of the school, the principal rushed to see the matter and found some children heating and chasing a small lizard. On seeing the principal, all the children fled to their classes except Alok who requested the principal to arrange for some medical assistance for the injured animal. The principal rewarded Alok for his attitude to save guard our biodiversity.
    (i) What do you understand by biodiversity?
    (ii) Mention the factors resulting in loss of biodiversity.
    (iii) Was Alok an indisciplined boy, who did not run to the class on seeing the principal? What values does the acts promote?

  • 3)

    During an excursion to a botanical garden, the teacher shows an old tree, which was on the verge of extinction. As soon as the teacher advanced with students, some enthusiastic students climbed up the tree and started cutting the branches, collecting its leaves as precious collection. Rajesh instead took photographs of the tree from various angles. The boys mocked at Rajesh while the teacher appreciated him
    (i) Why should we conserve biodiversity?
    (ii) How can biodiversity be conserved?
    (iii) What international initiatives were taken to conserve biodiversity?
    (iv) What values did Rajesh possess?

  • 4)

    On his visit to national park, Harshendra, was very angry as the forest authorities did not allow him to enter a specified area.
    On returning back, he discussed the matter with his friend, who explained him the reason.
    (i) Which category of conservation strategy does national park belong?
    (ii) Name India's first national park.
    (iii) At present, there are how many national parks in India?
    (iv) what values are shown by Harshendra's friend?

  • 5)

    Science & technology have added a number of gadgets to our lives. But they are creating e-waste problem. Geeta read a report on the disposal of these gadgets.
    Answer the following questions on the basis of above information:
    (i) What values are exhibited by Geeta ?
    (ii) What steps can be suggested by her for managing this problem?

CBSE 12th Standard Biology Subject Environmental Issues Value Based Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    While going to Nainital during summer vacations, Amitabh saw a board indicating the direction to Jim Corbett National Park. He asked his uncle, who happened to be a forest Officer, about national parks. He explained that national parks are maintained by government solely for the welfare of entire wild life in it
    read the above passage and answer the following questions:
    (i) How is wild life maintained in a national park?
    (ii) name two other national parks.
    (iii) What value is displayed by Amitabh's uncle?

  • 2)

    While explaining environmental issues, teacher makes a remark that 'Global warming is the most serious threat to civilisation now'. Kalpana gets curious about the various aspects of global warming and asks some questions to her teacher.
    (i) What is global warming?
    (ii) What are various causes of global warming?
    (iii) How can global warming be reduced? (iv) What values are shown by Kalpana?

  • 3)

    Public all over India is very much concerned about the deteriorating air quality in large parts of North India. Alarmed by this situation the Resident's Welfare Association of your locality organised an awareness programme entitled 'Bury not burn'. They invited you, being a biology student to participate.
    (i) How would you justify your arguments that promote burying and discourage burning? (Give two reasons)
    (ii) With the help of flowcharts, one for each practice, depict the chain of events that follow.

  • 4)

    Waste disposal and waste management poses a major problem in present times. Generation of garbage and its disposal is a major threat and consequently leads to severe environmental issues. The problem is not with biodegradable and recycled wastes. We realise that'the need is to reduce non-biodegradable wastes.
    (i) Why is there a great concern of managing non-biodegradable waste in comparison to biodegradable waste? Explain.
    (ii) As a member of eco-club of your school, suggest any two ways that you will discuss with your fellow members to organise for a 'Zero garbage day' once in a month in the school.

  • 5)

    Naman entered into a quarrel with some farmers who were spraying DOT in their field. Many people gathered at the spot to see and enjoy the incident. The angry mob demanded that Naman should not interfere in the farmer's job. Naman tried to explain his point and finally succeeded in explaining the harmful effects of DOT.
    (i) What is biomagnification? Explain with an example.
    (ii) Is biomagnification related with DDT only? Comment.
    (iii) What is the effect of DDT on birds?
    (iv) What values did Naman promote?

CBSE 12th Standard Biology Subject Environmental Issues Value Based Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Pollution is an undesirable change in physical, chemical and biological characteristics of environment, air, water, soil and land that has potential to adversely affect human life, the lives of the desirable species, natural resources, industrial processes and cultural assets.
    Given below are the sources of pollution and their effects. Using this information fill the spaces in the given box. Each pollutant may have more than one source and may show more than one effect.
    Pollutant source: Automobile exhaust, burning of fossils, refrigerant, agricultural field, fire extinguisher, paint solvents, deforestation, plastic foam.
    Effect: Photochemical smog, acid deposition, global warming, depletion of ozone.

    Name of pollutant Source Effect
    Chlorofluoro carbon (CFC) \(a\) \(p\)
    Suspended particulate matter (SPM) \(b\) \(q\)
    Oxides of nitrogen \(({ NO }_{ 2 })\) \(c\) \(r\)
    Sulphur dioxide \(({ SO }_{ 2 })\) \(d\) \(s\)
    Methane \(({ CH }_{ 4 })\) \(e\) t
  • 2)

    "To reduce or check the global warming is the biggest challenge. Scientist belive that this rise in temperature is leading to deletrious changes in environment and resulting in odd climates".
    (i) Write one difference between E1-nino and La-nino affect.
    (ii) Name any two agents which cause global warming.

  • 3)

    One day, Hari asked his uncle why can not he clear various types of wild plants in the vicinity of his village and use the land for cultivation of crops? Uncle replied that it will not be a wise step as plants other than crops are also essential for our survival.
    Read the above passage and answer the following question :
    (i) As a student of biology, in your opinion who is right Hari or His uncle and why ?
    (ii) What is the term used to denote the diversity among living things?
    (iii) What are the benefits of biodiversity?

  • 4)

    While visiting a national park, Ravi noticed a board with warning that hunting and killing of wild animals is a punishable crime. He failed to understand why killing a wild animal who may harm human beings, is a crime? He discussed it with his biology teacher who made him realise the importance of wild life for human survival.
    Read the above passage and answer the following questions:
    (i) How is our survival linked with the existence of wild animals?
    (ii) How can we protect these animals?
    (iii) What value is displayed by Ravi's teacher ?

  • 5)

    Satish heard about red data book in a TV programme on conservation of natural resources. He wanted to know in detail about this book so he discussed it with biology teacher who explained to him about this.
    Read the above passage and answer the following questions:
    (i) What is Red Data Book?
    (ii) What is the utility of this document?
    (iii) Who publishes this book?

CBSE 12th Standard Biology Subject Biotechnology: Principles and Processes Value Based Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Suresh thought of straight export of orchids as these flowers fetch high price in international market due to their beauty and longer vase life. He consulted his Botanist uncle who suggested him a fast method of propagation of orchids to earn good profits.
    Read the above passage and answer the following questions:
    (i) What is plant tissue culture ?
    (ii) What is micropropagation ?
    (iii) What value is displayed by Suresh's uncle ?

  • 2)

    Hari was a grower. He used to grow tomatoes on his fertile land and got very good yields. Science the vegetable market was far from his village and also he had no transport facility, most of his harvest was rotten due to delay. He consulted his friend in a agriculture university for solution to this problem who suggested him to grow transgenic tomatoes with delayed ripening genes.
    Read the above passage and answer the following questions:
    (i) What are transgenics?
    (ii) How are transgenic tomato produced?
    What value was displayed by Hari's friend?

  • 3)

    Rahul introduced Ronit to his uncle and told him that Ronit is pursuing course in biotechnology in America.
    His uncle had never of this term earlier and was curious to know about this term. Ronit pointed towards a big tree at the base of which were present numerous tumour-like structures and said that this is the example of natural biotechnology.
    (i) What is biotechnology?
    (ii) How these crown gall tumours are formed?
    (iii) What are the value shown by Rahul's uncle?

  • 4)

    The biology teacher was explaining about restriction enzymes and came to a point explaining that these enzymes are extracted from bacteria and are called as molecular scissors. Varun, a student got curious and asked some questions for more clarity on the concept to his teacher.
    (i) From which part of microorganisms are restriction enzymes derived?
    (ii) Why are restriction enzymes called molecular scissors?
    (iii) What if some strands are needed to be cut from within. would that lead to wastage of DNA?
    (iv) What value are shown by varun?

  • 5)

    No evidence was found on a crime scene, other than only a few hair strands. The inspector wants to proceed for DNA fingerprinting but the amount of DNA is very less.
    (i) In your opinion what could be the solution to this problem?
    (ii) Write the basic steps of this technique.
    (iii) Name the scientist who developed this technique.
    (iv) What values show by the inspector?

CBSE 12th Standard Biology Subject Biotechnology: Principles and Processes Value Based Questions 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    David came to India to meet hid friend Anil. Anil introduced him to his uncle and told that David is pursuing course in biotechnology. Uncle had never heard this term earlier and was curious to know about this term. David pointed towards a big tree at the base of which were present numerous tumour-like structures and said that this is the example of natural biotechnology.
    Read the above passage and answer the following questions :
    (i) What is biotechnology?
    (ii) How are crown gall tumours formed ?
    (iii) Why was uncle curious to know about biotechnology ?

  • 2)

    Shilpi heard about clones in cartoon serials on TV and also came to know about "Dolly" as a cloned sheep. She discussed it with her biology teacher who explained the meaning of clone and the method to raise the clones.
    Read the above passage and answer the following questions :
    (i) What is a clone ?
    (ii) How clones are produced in plants ?
    (iii) Why did Shilpi discuss the matter with her biology teacher ?

  • 3)

    No evidence was found on a crime scene, other than only a few hair strands. The inspector wants to proceed for DNA fingerprinting but the amount of DNA is very less.
    (i) In your opinion what could be the solution to this problem?
    (ii) Write the basic steps of this technique.
    (iii) Name the scientist who developed this technique.
    (iv) What values show by the inspector?

  • 4)

    Shubham was taught in the biotechnology class about the production of recombinant protein with the help of bioreactor. He was surprised by this new information. In the evening he discussed it with his elder brother, who is a biotechnologist. He smiled and explained him in detail.
    (i) Why is bioreactors useful in industries?
    (ii) What are the values shown by Shubham?

  • 5)

    Scientists are  now-a-days trying to produce the transgenic cattle in order to improve the quality and also quality of milk with special reference to its medicinal value. But there are some harmful side effects due to this procedure. Such transgenic animals get easily predispased to a variable number of diseases. This results in their shortening life span and ultimately an early death.On the basis of above information answer the following questions:
    (i) Should the scientists continue their efforts with their production of such transgenic cattle.
    (ii) What would be the reaction of different organization and community to such an act.
    (iii) What values are not being considered by the scientists in the above situation.

CBSE 12th Standard Biology Subject Biodiversity and Conservation Value Based Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Sanctuaries are tracts of land where animals are protected from all types of exploitation. Private ownership is permitted. Collection of minor sanctuaries are present in India?
    (i) How many sanctuaries are present in India?
    (ii) How much land area they cover?
    (iii) Name any three sanctuaries.
    (iv) List any three human activities are allowed in sanctuaries.

  • 2)

    During her tour to a renowned forest, Sakshi saw a highway being constructed, which passes through the middle of the forest. She was unhappy seeing that and on return, she I contacted the local eco-club and approached the concerned department to stop the work.
    (i) What would be the effect on biodiversity, if the highway is constructed?
    (ii) Howforests are useful to mankind?
    (iii) What values of Sakshi reflect here?

  • 3)

    Seeing a crowd of students in one corner of the school: the principal rushed to see the matter and found some children beating and chasing a small lizard. On seeing the principal, all the children fled to their classes except Alok who requested the principal to arrange for some medical assistance for the injured animal. The principal rewarded Alok for his attitude to save guard our biodiversity.
    (i) What do you understand by biodiversity?
    (ii) Mention the factors resulting in loss of biodiversity.
    (iii) Was Alokan indisciplined boy,who did not run to the class on seeing the principal? What values does the act promote?

  • 4)

    During an excursion to a botanical garden, the teacher shows an old tree, which was on the verge of extinction. As soon as the teacher advanced with the students, some enthusiastic students climbed up the tree and started cutting the branches, collecting its leaves as precious collection. Rajesh instead took photographs of the tree from various angles. The boys mocked at Rajesh while the teacher appreciated him.
    (i) Why should we conserve biodiversity?
    (ii) Howcan biodiversity be conserved?
    (iii) What international initiatives were taken to conserve biodiversity?
    (iv) What values did Rajesh possess?

  • 5)

    On his visit to a national park; Harshendra was very angry as the forest authorities did not allow him to enter a specified area. On returning back, he discussed the matter with his friend, who explained him the reason.
    (i) Which category of conservation strategy does national park belong?
    (ii) Name India's first national park.
    (iii) At present, there are how many national parks in India?
    (iv) Whatvalues are shownby Harshendra's friend?

CBSE 12th Standard Biology Subject Biodiversity and Conservation Value Based Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Sanctuaries are tracts of land where animals are protected from all types of exploitation. Private ownership is permitted. Collection of minor sanctuaries are present in India?
    (i) How many sanctuaries are present in India?
    (ii) How much land area they cover?
    (iii) Name any three sanctuaries.
    (iv) List any three human activities are allowed in sanctuaries.

  • 2)

    During her tour to a renowned forest, Sakshi saw a highway being constructed, which passes through the middle of the forest. She was unhappy seeing that and on return, she I contacted the local eco-club and approached the concerned department to stop the work.
    (i) What would be the effect on biodiversity, if the highway is constructed?
    (ii) Howforests are useful to mankind?
    (iii) What values of Sakshi reflect here?

  • 3)

    Seeing a crowd of students in one corner of the school: the principal rushed to see the matter and found some children beating and chasing a small lizard. On seeing the principal, all the children fled to their classes except Alok who requested the principal to arrange for some medical assistance for the injured animal. The principal rewarded Alok for his attitude to save guard our biodiversity.
    (i) What do you understand by biodiversity?
    (ii) Mention the factors resulting in loss of biodiversity.
    (iii) Was Alokan indisciplined boy,who did not run to the class on seeing the principal? What values does the act promote?

  • 4)

    During an excursion to a botanical garden, the teacher shows an old tree, which was on the verge of extinction. As soon as the teacher advanced with the students, some enthusiastic students climbed up the tree and started cutting the branches, collecting its leaves as precious collection. Rajesh instead took photographs of the tree from various angles. The boys mocked at Rajesh while the teacher appreciated him.
    (i) Why should we conserve biodiversity?
    (ii) Howcan biodiversity be conserved?
    (iii) What international initiatives were taken to conserve biodiversity?
    (iv) What values did Rajesh possess?

  • 5)

    On his visit to a national park; Harshendra was very angry as the forest authorities did not allow him to enter a specified area. On returning back, he discussed the matter with his friend, who explained him the reason.
    (i) Which category of conservation strategy does national park belong?
    (ii) Name India's first national park.
    (iii) At present, there are how many national parks in India?
    (iv) Whatvalues are shownby Harshendra's friend?

CBSE 12th Standard Biology Subject Biodiversity and Conservation Value Based Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    You find that a lake in your neighboring area has been covered by Water hyacinth. You have contacted your friends to remove this weed. Nobody agrees to support you. How will you explain the necessity of this?

  • 2)

    A well- known personality killed a black buck during hunting in sacred groves of Aravali Hills in Rajasthan. Local people caught him and lodged a case in court against him. He argued that court that killing a human being is a crime but killing an animal is not crime. What is your opinion?

  • 3)

    Students were taken for excursion to Arabari Joint forestry Project in Midnapore district, West Bengal .The various observations done by the students were as follows
    (i) Village people using forest products without causing harm to forest.
    (ii) Village people helping in plantation in deforestation areas.
    (iii) A core area under the forest is not disturbed by anybody. State the various inference which the students draw from the observations

  • 4)

    A sudden decline in fruits and seeds were seen in an area where regular heavy use of insecticides was done for the past few years. Give reasons for such an outcome.

  • 5)

    A debate was conducted on school on the need to conserve biodiversity. One student felt. that there are so many species on the earth, why will it matter if we lose a few. Do you feel the same. Justify your answer.

CBSE 12th Standard Biology Subject Biodiversity and Conservation Value Based Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    You find that a lake in your neighboring area has been covered by Water hyacinth. You have contacted your friends to remove this weed. Nobody agrees to support you. How will you explain the necessity of this?

  • 2)

    A well- known personality killed a black buck during hunting in sacred groves of Aravali Hills in Rajasthan. Local people caught him and lodged a case in court against him. He argued that court that killing a human being is a crime but killing an animal is not crime. What is your opinion?

  • 3)

    A sudden decline in fruits and seeds were seen in an area where regular heavy use of insecticides was done for the past few years. Give reasons for such an outcome.

  • 4)

    A debate was conducted on school on the need to conserve biodiversity. One student felt. that there are so many species on the earth, why will it matter if we lose a few. Do you feel the same. Justify your answer.

  • 5)

    Study-1. A forest that is rich in biodiversity seems to decline in animal population. The government declared it as a biodiversity hotspot and the forest regained its species richness in few years. Study-2. A lake that is rich in marine fishes seems to decline in its species population due to overexploitation. A wise man in the area decided to worship the lake. The species population f the lake again became normal.
    (a) Which values are been promoted in the above studies.
    (b) Suggest some ways by which you can contribute to this concern.
    (c) What would be the effect if the forest was not declared hotspot?

CBSE 12th Standard Biology Subject Ecosystem Value Based Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    One day, Ganesh asked his father why is government so much worried about decreasing population of tigers ? His father replied that it is important to save the tiger as they are at the end of food chains in forest ecosystem and play a role to keep the biotic components in ecosystem in balance.
    Read the above passage and answer the following questions:
    (i) What is a food chain ?
    (ii) What is an ecosystem ?
    (iii) What value is displayed by Ganesh's father?

  • 2)

    In every summer, Ravi used to visit his native village. Many years ago when he was a small child, a large amount of soil was removed from his village land for construction purpose and as a result a pond was formed after rainy season. Every year, he observed gradual changes in the vegetation of the pond.
    Read the above passage and answer the following questions:
    (i) What is the term used to describe the process of colonization of a new barren area?
    (ii) Define climax. What is the status of climax community?

  • 3)

    Grandfather told his grandson Arun that many years ago in Uttrakhand, villagers started a movement to save trees of Himalayas by hugging the trees whenever contractors came to cut trees. This movement was effective in saving our forest wealth.
    Read the above passage and answer the following questions:
    (i) What is the name given to this movement?
    (ii) How are trees imported for maintaining ecosystem?
    (iii) What value was displayed by villagers?

  • 4)

    Avinash went to his village during his summer vacations. One day, he decided to visit the nearby forest and asked his grandfather to accompany him. His grandfather told him about the recent cutting of forest and the new factory which had been established. Hearing this Avinash became curious and explained his grandfather about the ecosystem services.
    (i) What are the benefits of healthy forest ecosystem?
    (ii) Explain the contribution of Robert Constanza in ecosystem services.
    (iii) What factors account for cost of various ecosystem services?
    (iv) What values are shown by Avinash?

  • 5)

    Pragyan takes fruits, vegetables, bread and egg curry in a day's menu.While his teacher was giving a lecture on trophic level, he got fascinated and asked following questions from his teacher.
    (i) How many trophic levels does he occupy in different food chains?
    (ii) Represent atleast three food chains.
    (iii) Which among them gives him the maximum amount of energy? Give reason.
    (iv) What values are shown by Pragyan?

CBSE 12th Standard Biology Subject Ecosystem Value Based Questions 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    One day, Ganesh asked his father why is government so much worried about decreasing population of tigers ? His father replied that it is important to save the tiger as they are at the end of food chains in forest ecosystem and play a role to keep the biotic components in ecosystem in balance.
    Read the above passage and answer the following questions:
    (i) What is a food chain ?
    (ii) What is an ecosystem ?
    (iii) What value is displayed by Ganesh's father?

  • 2)

    Avinash went to his village during his summer vacations. One day, he decided to visit the nearby forest and asked his grandfather to accompany him. His grandfather told him about the recent cutting of forest and the new factory which had been established. Hearing this Avinash became curious and explained his grandfather about the ecosystem services.
    (i) What are the benefits of healthy forest ecosystem?
    (ii) Explain the contribution of Robert Constanza in ecosystem services.
    (iii) What factors account for cost of various ecosystem services?
    (iv) What values are shown by Avinash?

  • 3)

    Arun visited his grandfather's farm and noticed that one of the workers was introducing earthworms in the soil. He quickly rushed to his grandfather and asked him the reason. His grandfather explained him the advantages of earthworm in soil improvement.
    (i) Why are earthworms also known as detritivores?
    (ii) Explain fragmentation.
    (iii) Name the steps in the process ofdecomposition.
    (iv) What values are shown by Arun?

  • 4)

    Jeremy went to a butcher's shop with his father and saw that the goats before slaughter were fed on grasses and was fascinated to see the sequence of organism through which the food passes. On seeing his fascination his father asked him the reason and he quickly explained him the concept of food chain.
    (i) Describe food chain.
    (ii) Grass was eaten by goat which in turn is consumed by humans. Explain their relation.
    (iii) Name different types of food chains.
    (iv) What values are shown by Jeremy?

  • 5)

    Pragyan takes fruits, vegetables, bread and egg curry in a day's menu.While his teacher was giving a lecture on trophic level, he got fascinated and asked following questions from his teacher.
    (i) How many trophic levels does he occupy in different food chains?
    (ii) Represent atleast three food chains.
    (iii) Which among them gives him the maximum amount of energy? Give reason.
    (iv) What values are shown by Pragyan?

CBSE 12th Standard Biology Subject Organisms and Populations Value Based Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Organisms remain as individuals but interact as a group with other organisms and physical habitats and behave as population, community, ecosystem, etc.
    (a) What according to you, are the factors that account for the formation of major biomes?
    (b) Name any four major biomes of India.
    (c) What value is learnt from this statement?

  • 2)

    Water is the most important factor influencing the life of organisms.  Life on earth originated in water and cannot be sustained without water.  Organisms living in water bodies (ocean, lake, river, etc.) also face water-related problems.
    (a) How are aquatic animals affected by the quality of water? Explain.
    (b) Mention any four adaptations the desert plants have, to live there successfully.
    (c) Represent the value learnt.

  • 3)

    Himani while watching a TV programme based on life in polar region observed that all animals in polar regions possess larger size. Also, smaller animals are not found in that region. She asked about this surprising fact to her teacher.
    (i) why smaller animals (e.g. humming birds) are rarely found in polar regions?
    (ii) What are the adaptations shown by polar animals?
    (iii) What are the chief characteristics of polar region animals?
    (iv) What values are shown by Himani?

  • 4)

    A group of students visited a botanical garden, where they saw fungus growing on roots of higher plants only. They were confused seeing it then, their teacher told them that it is an interspecific interaction in which both species can be benefitted.
    (i) Write the name of this particular association
    (ii) How both are benefitted from each other?
    (iii) State use of this interaction to a farmer
    (iv) What values are shown by students

  • 5)

    Ramesh went to an excursion trip to Kumaun hills, along with his classmates, under an escort teacher. On reaching the destination, he all of a sudden started feeling nausea, heart pulpitation and fatigued. One of his friends and a classmate suggested him to take rest for some time.
    Answer the following questions on the basis of above information::
    (i) Suggest the reason of his not feeling well suddenly
    (ii) Why did his friend advise him to take rest for some time?
    (iii) What values were exhibited by his friend?

CBSE 12th Standard Biology Subject Organisms and Populations Value Based Questions 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    No species can exist alone in a habitat.  Any species has a minimal requirement of at least one more species, on which it can feed.  Interspecific interactions arise from the interaction of populations of two different species.
    (a) What term is given to the interaction, where one species is benefitted and the other is neutral?
    (b) Give four examples of the above kind of interaction.
    (c) How do you call the interaction where one species is neutral and the other is harmed? Give an example of such an interaction.
    (d) What value do you learn from this?

  • 2)

    'Struggle for existence and survival of the fittest' is Darwin's theory of Natural selection.  Interspecific competition, a potent force in organic evolution, is generally believed to occur between closely related species for the same resources, that are limiting, but this is not entirely true.
    (a) Give an example where totally unrelated species could compete with each other.
    (b) Resources need not be limiting for competition to occur.  Justify with an example.
    (c) What value is learnt from this?

  • 3)

    Ram saw that in his village farmers always used to plough the field before sowing seeds of any crop.He discussed his observation with his grandfather who explained that this practice helps to improve productivity  by providing better aeration, water absorption and availability of nutrients to plants.
    Read the above passage and answer the following questions:
    (i) What is soil?
    (ii) Which factors of soil affect soil fertility?
    (iii) What value is displayed by Ram?

  • 4)

    In a biology class, teacher was telling the students that the structures/components and their functions in a watch can be compared with various lenels of organisation we find in nature. Radhika was surprised and asked teacher to explain it. Teacher got impressed with Radhika's interest and explained that there is a systematic arrangement of smaller and simpler components into larger one in a hierarchy or pyramid having different levels where each level and itself is formed of components of lower level and itself becomes part of hgher level for achieving a common goal.
    (i) What are the four levels of biological organisation found in nature?
    (ii) What is the basic unit of ecological organisation
    (iii) Define community
    (iv) What value are shown by Radhika?

  • 5)

    A group of students visited a botanical garden, where they saw fungus growing on roots of higher plants only. They were confused seeing it then, their teacher told them that it is an interspecific interaction in which both species can be benefitted.
    (i) Write the name of this particular association
    (ii) How both are benefitted from each other?
    (iii) State use of this interaction to a farmer
    (iv) What values are shown by students

CBSE 12th Standard Biology Subject Biotechnology and its Applications Value Based Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Anil's grandfather read in the newspaper about golden rice. Being a farmer, he asked Anil to get more information from his teacher about this rice.Teacher explained to him that it is a new variety of rice which in precursor of vitamin A and his will be useful for rice eating poor population.
    Read the above passage and answer the following questions:
    (i) What is golden rice?
    (ii) Why is it beneficial for rice eating poor population?
    (iii) What values is displayed by Anil's grandfather?

  • 2)

    Monu's uncle is a diabetes patient and id dependent on insulin for diabetes treatment.Monu went to enquire about his health.His uncle told him that diabetes has become a very common problem due to change in life style and a lot of people need insulin for its treatment.Earlier, it was obtained from animals and was short in supply and costly but biotechnology has helped in making it cheaper and easily available.
    Read the above passage and answer the following questions:
    (i) What precautions will you take to avoid chances of diabetes?
    (ii) What is the role of insulin?
    (iii) How biotechnology is helpful in increased insulin production to benefit needy people?

  • 3)

    Umesh's grandfather went to village to meet his old friend, after a long time.He found that his friend who once was a big landlord became very poor. Grandfather asked the reason of his poverty in spite of so much land he possessed.He told that his land is suitable for growing cotton and every his crop is devastated by insect attacks and he has been suffering heavy losses.Grandfather consoled him and advised him to grow BT cotton in his fields.
    Read the above passage and answer the following questions:
    (i) What is BT Cotton?
    (ii) How has it been developed?
    (iii) How did grandfather help his friend in solving his financial problems?

  • 4)

    Sumit somewhere heard about banana vaccine.To know more about this vaccine, he discussed it with his uncle who was a professor of life sciences.Uncle told him that biotechnology has made possible to deliver vaccine to children through banana.
    Read the above passage and answer the following questions:
    (i) What is a vaccine?
    (ii) What is a banana vaccine? How is it beneficial to children?

  • 5)

    Sakshi's father announced that the children are going to spend this weekend with their grandparents. During the journey Sakshi saw some farmers who were spraying agrochemicals in their field. She requested her father to stop them. Her father praised her and contacted the farmers. He explained the side effects of such agrochemicals. He also suggested them to use biopesticides and bio fertilisers instead of such chemicals. The farmers gave up spraying agrochemicals.
    (i) What did Sakshi's father explain to the farmers?
    (ii) What are agrochemicals?
    (iii) Why are biofertilisers or biopesticides preferred to chemical fertilisers or pesticides?
    (iv) What values did Sakshi promote?

CBSE 12th Standard Biology Subject Biotechnology and its Applications Value Based Questions 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Anil's grandfather read in the newspaper about golden rice. Being a farmer, he asked Anil to get more information from his teacher about this rice.Teacher explained to him that it is a new variety of rice which in precursor of vitamin A and his will be useful for rice eating poor population.
    Read the above passage and answer the following questions:
    (i) What is golden rice?
    (ii) Why is it beneficial for rice eating poor population?
    (iii) What values is displayed by Anil's grandfather?

  • 2)

    Monu's uncle is a diabetes patient and id dependent on insulin for diabetes treatment.Monu went to enquire about his health.His uncle told him that diabetes has become a very common problem due to change in life style and a lot of people need insulin for its treatment.Earlier, it was obtained from animals and was short in supply and costly but biotechnology has helped in making it cheaper and easily available.
    Read the above passage and answer the following questions:
    (i) What precautions will you take to avoid chances of diabetes?
    (ii) What is the role of insulin?
    (iii) How biotechnology is helpful in increased insulin production to benefit needy people?

  • 3)

    Umesh's grandfather went to village to meet his old friend, after a long time.He found that his friend who once was a big landlord became very poor. Grandfather asked the reason of his poverty in spite of so much land he possessed.He told that his land is suitable for growing cotton and every his crop is devastated by insect attacks and he has been suffering heavy losses.Grandfather consoled him and advised him to grow BT cotton in his fields.
    Read the above passage and answer the following questions:
    (i) What is BT Cotton?
    (ii) How has it been developed?
    (iii) How did grandfather help his friend in solving his financial problems?

  • 4)

    Sumit somewhere heard about banana vaccine.To know more about this vaccine, he discussed it with his uncle who was a professor of life sciences.Uncle told him that biotechnology has made possible to deliver vaccine to children through banana.
    Read the above passage and answer the following questions:
    (i) What is a vaccine?
    (ii) What is a banana vaccine? How is it beneficial to children?

  • 5)

    Sakshi's father announced that the children are going to spend this weekend with their grandparents. During the journey Sakshi saw some farmers who were spraying agrochemicals in their field. She requested her father to stop them. Her father praised her and contacted the farmers. He explained the side effects of such agrochemicals. He also suggested them to use biopesticides and bio fertilisers instead of such chemicals. The farmers gave up spraying agrochemicals.
    (i) What did Sakshi's father explain to the farmers?
    (ii) What are agrochemicals?
    (iii) Why are biofertilisers or biopesticides preferred to chemical fertilisers or pesticides?
    (iv) What values did Sakshi promote?

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Value Based Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Recently, Anil read in an article that India and China have more than 70% of world livestock and there are about 227 million cattle in India. However, their contribution to the world farm produce is less than 25%. He also read that scientists are busy in developing breeds that are specially adapted for meat production, milk production and agriculture work especially in the hot climate.
    Read the above passage and answer the following questions:
    (i) How can we increase production of dairy products?
    (ii) How can we increase milk production?
    (iii) What value is displayed by Anil?

  • 2)

    One day, Geeta reached Delhi in the morning by train where she saw large consignment of flowers being unloaded from train. She asked her father why so much cut flowers were being brought to Delhi. Her father replied that growing flowers is a very good commercial activity and Delhi is a good market from where flowers are also exported.
    Read the above passage and answer the following questions:
    (i) What is floriculture?
    (ii) What are the methods of increasing commercial production of plants?
    (iii) Why did floriculturists bring cut flowers to Delhi?

  • 3)

    What is single cell protein? Give its importance and two examples of SCP?

  • 4)

    It is surveyed that almost 25% of crop produce is destroyed by insects and pests. To overcome this problem the agriculturists have developed some strategies. Explain them.

  • 5)

    A number of pest and disease resistant varieties of crop plants have been developed during recent years for increasing the agricultureal yield. However there are some side effects of such an increased agricultural production. This has led to development of super pest and super weed which are not controlled by routine method. They require some special scientific inputs to control them.
    Answer the following questions based on the above information.
    (i) Should such a practise of pest control continue?
    (ii)What other methods should be practised to manage the pest and diseases to increase the agricultural yield.
    (iii)What values have not been exhibited in above case.

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Value Based Questions 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Rohit was a milkman. Once, he asked his father that he has heard about high milk yielding cows but has no idea from where he can procure such a variety of cow. Rohit's father, being an agricultural scientist, solved his son's problem.
    Read the above passage and answer the following questions:
    (i) What is artificial insemination?
    (ii) Name two superior varieties of cows.
    (iii) How did his father help his son Rohit?

  • 2)

    Recently, Anil read in an article that India and China have more than 70% of world livestock and there are about 227 million cattle in India. However, their contribution to the world farm produce is less than 25%. He also read that scientists are busy in developing breeds that are specially adapted for meat production, milk production and agriculture work especially in the hot climate.
    Read the above passage and answer the following questions:
    (i) How can we increase production of dairy products?
    (ii) How can we increase milk production?
    (iii) What value is displayed by Anil?

  • 3)

    Arvind was jobless for quite some time and was thinking of some business with low investment in his village which has abundance of flowering plants of various types. One day, he expressed his desire to his uncle who was an agricultural scientist. He advised him to start bee-keeping in his village.
    Read the above passage and answer the following questions:
    (i) What is bee keeping?
    (ii) What are the products obtained from bee keeping?
    (iii) What information is required for successful bee keeping?

  • 4)

    Suresh is an owner of a good dairy farm. He made up his mind to improve and develop the farm by introducing the MOET technique. Therefore he purchased a high milk yielding breed of cow. To his good luck he earned a lot of money by selling the calves but very soon this cow met premature death. One of his friend Mahesh objected to his practise and earning money in such a way.
    Answer following questions on the basis of this information.
    (i) Expand MOET. 
    (ii) Describe the process in brief. 
    (iii) What values were exhibited by Mahesh, a friend of suresh.

  • 5)

    A number of pest and disease resistant varieties of crop plants have been developed during recent years for increasing the agricultureal yield. However there are some side effects of such an increased agricultural production. This has led to development of super pest and super weed which are not controlled by routine method. They require some special scientific inputs to control them.
    Answer the following questions based on the above information.
    (i) Should such a practise of pest control continue?
    (ii)What other methods should be practised to manage the pest and diseases to increase the agricultural yield.
    (iii)What values have not been exhibited in above case.

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Value Based Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Differentiate between inbreeding and out breeding in cattle. State on eadvantage and on edisadvantage for each one of them.

  • 2)

    Expand MOET. Explain the procedure of this  technology in cattle improvement.

  • 3)

    Viruses are principally composed of nucleoproteins. Virus is an obligate parasite. It is inert outside the host cell. An inert virus is called virion. It can be crystallised and stored indefinitely. A biosynthetic machinery is absent. There is no system to liberate energy. A virus does not grow. It does not divide or reproduce like typical organism. Instead it multiplies by independent formation of its parts using host machinery and then assembly of parts occurs to produce virus particles. A assembly of parts occurs to produce virus particles. A virus lacks irritability and motility. It requires a vector for transfer from one host to another. They are major for transfer from one host to another. They are major cause of disease in humans; some diseases of agriculturally important animals and plants are also known to be caused by viruses.
    Read the passage and answer the following questions.
    (i) Viruses cause damage to plants. Name two viral diseases of plant and their causative organisms.
    (ii) Describe any method to obtain viral free plant for better yield.

  • 4)

    Biofortification is a method of breeding crops with higher levels of vitamins and minerals or higher proteins and healthier fats in the view of improving public health.
    (1) Give examples of biofortified food.
    (2) How is this process useful in controlling night blindness in poor countries.

  • 5)

    Teacher explains about the process of biofortification, in which he explains that, this method is useful in providing nutrition to large population. Akshay asked some question about this from his teacher.
    (i) What is biofortification?
    (ii) What types of nutritional enrichment can be possible through this?
    (iii) What is Atlas 66?
    (iv) What values are shown by Akshay as biology student?

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Value Based Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Differentiate between inbreeding and out breeding in cattle. State on eadvantage and on edisadvantage for each one of them.

  • 2)

    Expand MOET. Explain the procedure of this  technology in cattle improvement.

  • 3)

    Viruses are principally composed of nucleoproteins. Virus is an obligate parasite. It is inert outside the host cell. An inert virus is called virion. It can be crystallised and stored indefinitely. A biosynthetic machinery is absent. There is no system to liberate energy. A virus does not grow. It does not divide or reproduce like typical organism. Instead it multiplies by independent formation of its parts using host machinery and then assembly of parts occurs to produce virus particles. A assembly of parts occurs to produce virus particles. A virus lacks irritability and motility. It requires a vector for transfer from one host to another. They are major for transfer from one host to another. They are major cause of disease in humans; some diseases of agriculturally important animals and plants are also known to be caused by viruses.
    Read the passage and answer the following questions.
    (i) Viruses cause damage to plants. Name two viral diseases of plant and their causative organisms.
    (ii) Describe any method to obtain viral free plant for better yield.

  • 4)

    Biofortification is a method of breeding crops with higher levels of vitamins and minerals or higher proteins and healthier fats in the view of improving public health.
    (1) Give examples of biofortified food.
    (2) How is this process useful in controlling night blindness in poor countries.

  • 5)

    Teacher explains about the process of biofortification, in which he explains that, this method is useful in providing nutrition to large population. Akshay asked some question about this from his teacher.
    (i) What is biofortification?
    (ii) What types of nutritional enrichment can be possible through this?
    (iii) What is Atlas 66?
    (iv) What values are shown by Akshay as biology student?

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Value Based Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    What is interspecific hybridization? Write one example of it.

  • 2)

    What role is played by heterozygosity in the improvement of breeds?

  • 3)

    Write the economic importance of honey bee.

  • 4)

    How would an aquaculture and pisciculture be helpful in our life?

  • 5)

    How micro-propagation is helpful in producing thousands of plant?

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Value Based Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    What is interspecific hybridization? Write one example of it.

  • 2)

    What role is played by heterozygosity in the improvement of breeds?

  • 3)

    Write the economic importance of honey bee.

  • 4)

    How would an aquaculture and pisciculture be helpful in our life?

  • 5)

    How micro-propagation is helpful in producing thousands of plant?

CBSE 12th Standard Biology Subject Human Health and Disease Value Based Questions 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Grandfather advised his grandson Manoj that he must his wash his hands before meals and he always followed his advice. This habit helped in protecting him from a number of infectious diseases. In contrast, his friend seldom bothered to wash his stands and frequently suffered from one or the other disease and therefore, was very weak physically as well as in studies.
    Read the above passage and answer the following questions:
    (i) What happens when we wash our hands?
    (ii) Name two diseases from which you can get protection by washing hands?
    (iii) What values are displayed by grandfather?

  • 2)

    Municipal employee were taking samples of water from the coolers, flower pots and stagnant water at public places. Amit enquired from them about the purpose of this exercise. They replied that they were looking for the presence of larvae of mosquitoes in these samples.
    Read the above passage and answer the following questions:
    (i) Why were municipal employees looking for the presences of mosquitoes larvae?
    (ii) Name three diseases spread by mosquitoes.
    (iii) What value is displayed by municipal employees?

  • 3)

    After consuming sugarcane juice from a roadside vendor, Monu suffered from cough. His mother advised him to cover his nose while coughting and sneezing.
    Read the above passage and answer the following questions:
    (i) Why did Monu fall ill?
    (ii) Why did his mother advise him to cover his nose while coughting and snazing?

  • 4)

    Janaki's mother went to see her maid who recently gave birth to a baby, Janaki,s mother gifted maid a set of clothes for the new born and advised her to get the child vaccinated timely but maid replied that she was very poor and cloud not afford the cost of vaccines.
    Read the above passage and answer the following questions:
    (i) What are vaccines?
    (ii) Name two vaccines given to new born babies.
    (iii) How did Janaki's mother help the maid to get her new born vaccinated free of cost?

  • 5)

    A number of personnel were deputed by municipal corporation to check mosquito breeding in your school.
    On the basis of this information answer the following questions:
    (i) What places they should search for checking mosquito breeding?
    (ii) Name two diseases caused by mosquitoes.
    (iii) Name any two biological agents which can bring about the biocontrol of mosquitoes.

CBSE 12th Standard Biology Subject Human Health and Disease Value Based Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    (a)Name the infective stage of Plasmodium which Anopheles mosquito take along with the blood meal from an infected human.
    (b)Why does the infection cause fever in humans?
    (c)Give a flow chart of the part of the life-cycle of this parasite passed in the insect.

  • 2)

    Name any two organisms that are responsible for ringworms in humans. Mention two diagnostic symptoms. Name the specific parts of the human body where these organisms thrive and explain why?
    (i) Name any two causative organisms responsible for ringworm.
    (ii) State any two symptoms of the disease.

  • 3)

    Some international sports persons failed in dope tests& not allowed to participate in Olympics as they were drug abusers
    i) Name the drugs that would have been taken by them.
    ii) Why did they use such drugs?

  • 4)

    Some human diseases are transmitted only when the blood of a patient comes in contact with the blood of a healthy person. In one of such disease, there is a progressive decrease in the number of lymphocytes of the patient.
    i) Name the disease & its causative agent
    ii) Name the type of lymphocytes affected due to this infection.

  • 5)

    Health is the basic to life, and is essential for the good results in any sphere of life. A factory owner cannot expect the optimum output, if he does not employ healthy workers. A farmer cannot get optimum yield in his fields, if he is not healthy What does health actually mean? How is it related to our personal life & professional efficiency?

CBSE 12th Standard Biology Subject Human Health and Disease Value Based Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Some international sports persons failed in dope tests& not allowed to participate in Olympics as they were drug abusers
    i) Name the drugs that would have been taken by them.
    ii) Why did they use such drugs?

  • 2)

    Some human diseases are transmitted only when the blood of a patient comes in contact with the blood of a healthy person. In one of such disease, there is a progressive decrease in the number of lymphocytes of the patient.
    i) Name the disease & its causative agent
    ii) Name the type of lymphocytes affected due to this infection.

  • 3)

    Health is the basic to life, and is essential for the good results in any sphere of life. A factory owner cannot expect the optimum output, if he does not employ healthy workers. A farmer cannot get optimum yield in his fields, if he is not healthy What does health actually mean? How is it related to our personal life & professional efficiency?

  • 4)

    (i) List any two situations, when a medical doctor would recommend injection of preformed antibodies into the body of a patient. Name this kind of immunisation and mention its advantages.
    (ii) Name the kind of immunity attained when instead of antibodies, weakened antigens are introduced into the body.

  • 5)

    Name the following:
    (a) The vector of dengue fever.
    (b) A vaccine produced by recombinant DNA technology.
    (c) The type of immunity that is present at the time of birth.
    (d) A fish that helps in eradication of mosquito larvae.

CBSE 12th Standard Biology Subject Evolution Value Based Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    One day, father complained of severe pain in the abdomen. Naresh took him to doctor for examination. Doctor diagnosed it to be a case appendicitis and advised immediate surgical removal of vermiform appendix.
    Read the above passage and answer the following questions:
    (i) What is appendicitis?
    (ii) What is vermiform appendix?
    (iii) What value was displayed by Naresh?

  • 2)

    One day, while returning home from school, Anil saw a crowd gathering front of Mr. Sharma's house. He asked his mother about it. She told that Mrs. Sharma gave birth to a child with small tail. Many people gathered just for curiosity and some whispered that it is a bad omen.
    Read the above passage and answer the following questions:
    (i) What is your opinion about child?
    (ii) What is atavism?
    (iii) What will be your role as a good citizen and student of biology?

  • 3)

    Doctor are worried about antibiotics resistance in disease causing bacteria such as Mycobacterium and are using DNA fingerprinting technique for screening of resistance bacteria.
    Read the above passage and answer the following questions:
    (i) What is antibiotics?
    (ii) What are the possible reasons for development of resistance in bacteria to antibiotics?
    (iii) How can DNA fingerprinting be helpful in controlling growth of such bacteria?

  • 4)

    Samya visited a zoo with her mother on watching the cheetah she wondered how he uses his forelimbs for running.While the same forelimbs in bats are used for flying.she want to know about it ask her mother about it.Her mother explains different animal groups for different functions.
    (i)What are such organs called?
    (ii)Give an example of such organs from the plant world
    (iii)What led to the origin of such organs?
    (iv)What are the values shown by samya?

  • 5)

    ranjana and shilpi had a hot argument whether or not life is still originating on the earth today.Their neighbour Mr kamal mishra to the girl called them and explained the matter in details.
    (i)As a student of biology,what is your answer to the question ? why?
    (ii)Recall the experiment of Miller,which simulated the primitive atmosphere
    (a)What were the products obtain his experiment
    (b)How aws energy provide in experiment?
    (iii)What would have energy source for orgin of life on the earth?
    (iv)Indicate the value shown by Mr.kamal mishra?

CBSE 12th Standard Biology Subject Evolution Value Based Questions 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    One day, father complained of severe pain in the abdomen. Naresh took him to doctor for examination. Doctor diagnosed it to be a case appendicitis and advised immediate surgical removal of vermiform appendix.
    Read the above passage and answer the following questions:
    (i) What is appendicitis?
    (ii) What is vermiform appendix?
    (iii) What value was displayed by Naresh?

  • 2)

    One day, while returning home from school, Anil saw a crowd gathering front of Mr. Sharma's house. He asked his mother about it. She told that Mrs. Sharma gave birth to a child with small tail. Many people gathered just for curiosity and some whispered that it is a bad omen.
    Read the above passage and answer the following questions:
    (i) What is your opinion about child?
    (ii) What is atavism?
    (iii) What will be your role as a good citizen and student of biology?

  • 3)

    Ramu was spraying white powder in the street near the stagnant water. Anil enquired about this substance and Ramu told him that it was DDT powder which is used to kill mosquitoes. He further said that earlier this powder was very effective in controlling mosquitoes growth but now it is not so effective.
    Read the above passage and answer the following questions:
    (i) What is the possible reason for ineffectiveness of DDT led to the development of resistance in the mosquitoes.
    (ii) What message would you like to give to the society?

  • 4)

    Doctor are worried about antibiotics resistance in disease causing bacteria such as Mycobacterium and are using DNA fingerprinting technique for screening of resistance bacteria.
    Read the above passage and answer the following questions:
    (i) What is antibiotics?
    (ii) What are the possible reasons for development of resistance in bacteria to antibiotics?
    (iii) How can DNA fingerprinting be helpful in controlling growth of such bacteria?

  • 5)

    Samya visited a zoo with her mother on watching the cheetah she wondered how he uses his forelimbs for running.While the same forelimbs in bats are used for flying.she want to know about it ask her mother about it.Her mother explains different animal groups for different functions.
    (i)What are such organs called?
    (ii)Give an example of such organs from the plant world
    (iii)What led to the origin of such organs?
    (iv)What are the values shown by samya?

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance Value Based Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    In a maternity ward, two new born babies got exchanged and two women claiming to be the mother of one child and the matter went to the court.The judge asked to conduct DNA test of the child and two women, and on the basis of report settled the issue of paternity
    Read the above passage and answer the following questions:
    (i)What is the meaning of DNA test?
    (ii)How is it helpful in deciding paternity issues?

  • 2)

    In a recent case of crime, there were no witness and Ramesh was the first person to reach the site.He did not allow any onlookers to distrub the scene of crime and called the police.Careful examination by forensic experts revealed the presence of some hairs from the site of crime which helped the police to nail the culprit.
    |Read the above passage and answer the following questions:
    (i) In your opinion, by which method this was possible?
    (ii) What is DNA fingerprinting?
    (ii) What value is displayed by Ramesh?

  • 3)

    Ramesh somewhere heard about human genome project.He discuss it with his biology teacher who explained that is a comprehensive project(approx.cost9 billion dollars)undertaken by molecular biologists to completely map the entire human genome by determining the complete nucleotide sequences of DNA of each chromosome (22 autosoms and X, Y sex chromosomes.)
    Read the above passage and answer the following questions:
    (i) What is genomics?
    (ii) What is importance of Human Genome Project?

  • 4)

    Ranjit,while coming back home,saw a person on motorbike who was using mobile phone while driving and he met with an accident.Motorcyclist was badly hurt and was profusely bleeding.As a good citizen, Ranjit took him to hospital immediately where doctors after examining advised immediate blood transfusion to save his lifr.Ranjit offered doctors his blood but they refused as his blood group was not compatible with that of the victim.
    Read the above passage and answer the following questions:
    (i)What are blood, groups?
    (ii)Why have different people different blood groups?
    (iii)What value is displayed by Ranjit?

  • 5)

    Raj was a known sportsman in his school.While returning home he found unknown miscreants beating a young fellow.He tried to drive them off but by that time the fellow died of injury.The police arrested Raj and he was put on trial.The judge being convinced by Raj's plea, ordered for DNA fingerprinting reports.
    (i) What is the basis of DNA fingerprinting?
    (ii) Explain the steps in DNA fingerprinting.
    (iii) Write the applications of DNA fingerprinting.
    (iv) Raj's fingerprints on the dead body were sufficient to convict him but the judge asked for authentic proof.What values can observed by the judge?

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance Value Based Questions 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    In a maternity ward, two new born babies got exchanged and two women claiming to be the mother of one child and the matter went to the court.The judge asked to conduct DNA test of the child and two women, and on the basis of report settled the issue of paternity
    Read the above passage and answer the following questions:
    (i)What is the meaning of DNA test?
    (ii)How is it helpful in deciding paternity issues?

  • 2)

    In a recent case of crime, there were no witness and Ramesh was the first person to reach the site.He did not allow any onlookers to distrub the scene of crime and called the police.Careful examination by forensic experts revealed the presence of some hairs from the site of crime which helped the police to nail the culprit.
    |Read the above passage and answer the following questions:
    (i) In your opinion, by which method this was possible?
    (ii) What is DNA fingerprinting?
    (ii) What value is displayed by Ramesh?

  • 3)

    Ramesh somewhere heard about human genome project.He discuss it with his biology teacher who explained that is a comprehensive project(approx.cost9 billion dollars)undertaken by molecular biologists to completely map the entire human genome by determining the complete nucleotide sequences of DNA of each chromosome (22 autosoms and X, Y sex chromosomes.)
    Read the above passage and answer the following questions:
    (i) What is genomics?
    (ii) What is importance of Human Genome Project?

  • 4)

    Ranjit,while coming back home,saw a person on motorbike who was using mobile phone while driving and he met with an accident.Motorcyclist was badly hurt and was profusely bleeding.As a good citizen, Ranjit took him to hospital immediately where doctors after examining advised immediate blood transfusion to save his lifr.Ranjit offered doctors his blood but they refused as his blood group was not compatible with that of the victim.
    Read the above passage and answer the following questions:
    (i)What are blood, groups?
    (ii)Why have different people different blood groups?
    (iii)What value is displayed by Ranjit?

  • 5)

    Garima is a bright fair girl but orphan by birth. One she got much disturbed after learning that a couple had claimed her to be their daughter. Although it is good but she felt that she did not belong to them. One of her close friends Nisha who was very much caring for her contacted the orphanaqe executives to find out the validity of the claim of the couple through DNA profiling.
    Answer the following questions on the basis of above information:
    (i) How DNA profiling can be made use of for testing the validity of parenthood claim of the couple.
    (ii) Which branch of biology was this programme associated with?
    (iii) What values were shown by Nisha.

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation Value Based Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    One day, while remembering about earlier time, Monu's grandfather told him that the country has made tremendous progress in the field of food grain production after green revolution. He further told that earlier we used to import wheat from other countries to feed the huge population.
    (i) What is green revolution?
    (ii) How was it achieved?
    (iii) What value is displayed by grandfather?

  • 2)

    Anil got selected in Indian Forest Service examination and was asked to appear before medical board to check his medical fitness for this service.On examination, doctor found him suffering from colour blindness.Knowing this, he consulted his family doctor to know about the reason when none of his family members was so. Doctor explained that it is due to sex linked inheritance.
    (i) What is colour blindness?
    (ii) What is sex linked inheritance?
    (iii) As a student of biology, what would you suggest to Anil so that his children are not colour blind?

  • 3)

    Priya's aunt gave birth to a child with cleft palate. Being a student of biology, Priya was curious to know the reason for this abnormality. So, she discussed this matter with her biology teacher. Teacher explained to her that it is a genetic disorder which is due to the defect in one of the chromosomes of the child.
    (i) What are genetic disorders?
    (ii) What are the possible causes of genetic disorders?
    (iii) As a student of biology, how would you create awareness in society about these disorders?

  • 4)

    Sunny was rushed to a nearby hospital after an accident, which had caused too much blood loss. The hospital failed to supply O negative blood for transfusion. Ahmed, who was attending a patient there, heard about the situation and agreed to donate blood as he had the same blood group. Sunny's mother initially refused but was later convinced by her daughter's view.
    (i) Why can't O positive blood be transfused into Sunny's body?
    (ii) Human blood grouping is an example of?
    (iii) What values do you find in Sunny's sister and Ahmed?

  • 5)

    In a court of law, two couples X and Y, claim a child Z of blood group O as theirs. Couple X has man with blood group O and woman with blood group AB. Couple Y has man with blood group A and woman with blood group B. So, a geneticists helps in solving the problem but the judge ordered for use of more recent and advance techniques and then the child was handed over ultimately to couple Y.
    (i) Is it a correct judgement regarding the true/biological parents of the child? Justify with your knowledge of genetics.
    (ii) Name the other technique that the judge has ordered for solving this problem.
    (iii) Indicate the value(s)  exhibited by the judge.

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation Value Based Questions 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Sonu was very fond of gardening. He used to bring seeds of the flowers he liked from different places. Many times, he observed that all plants obtained from seeds were not similar. He discussed the observations with his biology teacher who explained that this is due to phenomenon of crossing over.
    (i) What is crossing over?
    (ii) What is the significance of cross over?
    (iii) How can crossing over be used for commercial purposes?
    (iv) What value is displayed by teacher?

  • 2)

    One day, while remembering about earlier time, Monu's grandfather told him that the country has made tremendous progress in the field of food grain production after green revolution. He further told that earlier we used to import wheat from other countries to feed the huge population.
    (i) What is green revolution?
    (ii) How was it achieved?
    (iii) What value is displayed by grandfather?

  • 3)

    Anil got selected in Indian Forest Service examination and was asked to appear before medical board to check his medical fitness for this service.On examination, doctor found him suffering from colour blindness.Knowing this, he consulted his family doctor to know about the reason when none of his family members was so. Doctor explained that it is due to sex linked inheritance.
    (i) What is colour blindness?
    (ii) What is sex linked inheritance?
    (iii) As a student of biology, what would you suggest to Anil so that his children are not colour blind?

  • 4)

    Priya's aunt gave birth to a child with cleft palate. Being a student of biology, Priya was curious to know the reason for this abnormality. So, she discussed this matter with her biology teacher. Teacher explained to her that it is a genetic disorder which is due to the defect in one of the chromosomes of the child.
    (i) What are genetic disorders?
    (ii) What are the possible causes of genetic disorders?
    (iii) As a student of biology, how would you create awareness in society about these disorders?

  • 5)

    Sunny was rushed to a nearby hospital after an accident, which had caused too much blood loss. The hospital failed to supply O negative blood for transfusion. Ahmed, who was attending a patient there, heard about the situation and agreed to donate blood as he had the same blood group. Sunny's mother initially refused but was later convinced by her daughter's view.
    (i) Why can't O positive blood be transfused into Sunny's body?
    (ii) Human blood grouping is an example of?
    (iii) What values do you find in Sunny's sister and Ahmed?

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation Value Based Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    A child born to a couple was claimed by another man in the hospital. What is the methodology used to solve the paternity dispute?

  • 2)

    Two claimant fathers filed a case against a lady claiming to be the father of her only daughter. How could this case be settled identifying the real biological father?

  • 3)

    The police department could obtain a bunch of hair from the gripped hand of a murdered man. There were two persons arrested in this criminal case. How will the forensic department, give a clue to the criminals?

  • 4)

    A man with blood group A and his wife blood group B have a son with blood group O, father claim that was not his son. How can the problem be solved?

  • 5)

    Give an example of a gene responsible for multiple phenotypic expressions. What are such genes called? State the cause that is responsible for such an effect.

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation Value Based Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    A child born to a couple was claimed by another man in the hospital. What is the methodology used to solve the paternity dispute?

  • 2)

    Two claimant fathers filed a case against a lady claiming to be the father of her only daughter. How could this case be settled identifying the real biological father?

  • 3)

    The police department could obtain a bunch of hair from the gripped hand of a murdered man. There were two persons arrested in this criminal case. How will the forensic department, give a clue to the criminals?

  • 4)

    A man with blood group A and his wife blood group B have a son with blood group O, father claim that was not his son. How can the problem be solved?

  • 5)

    Give an example of a gene responsible for multiple phenotypic expressions. What are such genes called? State the cause that is responsible for such an effect.

CBSE 12th Standard Biology Subject Reproductive Health Value Based Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Amit observed that the children of labourers, working at the construction site of his new house, were not having proper clothes and malnourished. He asked sympathetically to one of the labourers the reason of possible condition of their children. Labourer told him that he does not earn enough to fulfil the needs of his family. Amit suggested that although he can not increase his income but he can control his family size by using birth control techniques and advised him to go to the nearest primary health centre where such devices are freely available.
    Read the above passage and answer the following questions:
    (i)  What value is displayed by Amit?
    (ii)  What are the methods available for birth control?
    (iii)  What is the additional advantage of using condom?

  • 2)

    Ravi saw that in the city at several places banners were displayed advising people to visit Red Ribbon Express Train standing at railway station of his city. He became curious and reached station. There, he came to know that the train was there to spread awareness about AIDS.
    Read the above passage and answer the following questions:
    (i)  What is AIDS?
    (ii)  What are the methods to stop the spread of AIDS?
    (iii) What are the misconceptions about AIDS?
    (iv)  What value is displayed by Ravi?

  • 3)

    On world population day, Rohit and his friends arranged an awareness campaign on population explosion programme in their locality. Some elderly people tried to stop the children and asked them not to talk about such things in public.
    The children convinced the elders about the need for the programme and on understanding their point of view, the elders also joined the campaign.
    (i) Why is such awareness programme necessary?
    (ii) What role has the government played in controlling population explosion?
    (iii) When were reproductive health programmes initiated in India?
    (iv) What values did Rohit and his friends show on the occasion?

  • 4)

    Some parents wrote a complaint letter to the local municipality to remove all the hoardings in the city, advertising the use of condoms and matters relating to AIDS prevention. The children of these parents came to know about the matter and raised their voice against the removal of the hoardings. The parents were convinced by the awareness level of their children and withdrew the complaint.
    (i) Parents considered the hoarding as inappropriate. Do you agree/disagree with their view?
    (ii) What are the methods by which AIDS spreads?
    (iii) What is AIDS?
    (iv) What values are promoted by the children protesting against their parents?

  • 5)

    During a visit to Vaishno Devi, Rahul came across a young couple staying in the adjacent room in the hotel.
    He learned that the couple had been visiting different temples and performing rituals to get a child. Rahul was astonished and explained to them about ART which he had recently studied in biology. The couple were happy and understood their wrong approach and thanked Rahul.
    (i) What is ART? What is the various method included in ART?
    (ii) What are the limitations for which ART is not commonly accepted?
    (iii) Identify the values which Rahul showed.

CBSE 12th Standard Biology Subject Reproductive Health Value Based Questions 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    The total human population is over 6 billion.Population of India is 1.21 billion.The number of individuals inhabiting per unit area is known as population density.Population density of India was in\(178/{ km }^{ 2 }\) 1971, \(216/{ km }^{ 2 }\) in 1971. Bangladesh, Japan, and Netherland are the most thickly populated countries with density of population being in\(617/{ km }^{ 2 }\) Bangladesh and in \(319/{ km }^{ 2 }\) Netherland.
    Answer the questions:
    (i) What are consequences of overpopulation in India?
    (ii) List any three measure to avoid pregnancy.
    (iii) What are side-effects of use of steroidal pills as contraceptive?

  • 2)

    Reproductive and Child Healthcare (RCH) programmes are currently in operation. One of the major tasks of these programmes is to create awareness amongst people about the wide range of reproduction related aspects.As this is important and essential for building a reproductive health society.
    (a) "Providing sex education in schools in one of the ways to meet this goal". Give four points in support of your opinion regarding this statement BSC
    (b) List any two indicators that include a reproductively society.

  • 3)

    While travelling, Arvind noticed that in his city every public transport, whether bus or train, was full of passengers and there was no space even in the markets or other public places. He shared his observation with his grandfather. Grandfather told him that the situation was not so worse when he was a child. Population has increased so much that we do not have sufficient resources to provide basic amenities needed in a civillized society.
    Read the above passage and answer the following questions:
    (i)  Whar are the possible reasons of population explosion?
    (ii)  What are the adverse effect of such population explosion?
    (iii) As an educated citizen, what are your suggestion to reserve the trend?

  • 4)

    One day, Monu did not go to school as he was not feeling well and on listening the sound of door bell he opened the door and saw two health workers at his doorstep. These health workers asked whether there was may any child of less than five years in his so that they could give him polio drops. He replied in affirmative and called his younger brother. They asked him to open his mouth and put two drops in his mouth from a vial. His neighbour, however, hid his child from health workers.
    Read the above passage and answer the following questions:
    (i)  Who took the right decision Monu or his neighbour?
    (ii)  What was the need of giving polio drops?
    (iii) What other vaccines are given to newborn?

  • 5)

    Ravi saw that in the city at several places banners were displayed advising people to visit Red Ribbon Express Train standing at railway station of his city. He became curious and reached station. There, he came to know that the train was there to spread awareness about AIDS.
    Read the above passage and answer the following questions:
    (i)  What is AIDS?
    (ii)  What are the methods to stop the spread of AIDS?
    (iii) What are the misconceptions about AIDS?
    (iv)  What value is displayed by Ravi?

CBSE 12th Standard Biology Subject Human Reproduction Value Based Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Ramesh got a job in Mumbai but his family was still living in the village. One day, he received a letter from his father stating that he is planning marriage of her sister who will be fifteen years old in March. Ramesh did not like the idea of his father of arranging plan of his sister till she attains age of 18 years.
    Read the above passage and answer the following questions:
    (i) In your opinion, who is right Ramesh or his Father?
    (ii) What is the right age of marriage for girls?
    (iii) What are the risks involved in early marriage?

  • 2)

    Purnima visited her native village with her grandmother. In the village, she saw some ladies, even pregnant, were smoking bidies. She also saw a child cleft palate in the lap of one of the returns home. On the way, she told Dadaji that she is planning to start campaign to make these illiterate women aware about ill effects of tobacco on health.
    Read the above passage and answer the following questions:
    (i)   Is there any harmful effect of use of tobacco smoking on our health?
    (ii)  Explain briefly the effects of smoking on human health?
    (iii) What is the effects of tobacco on next generation?

  • 3)

    Meena was shopping wth her children in the market where she met her friend Sunita after many years. During talks, Meena asked the reason of her sadness. Sunita told that even after three years of marriage she is not able to bear child and sarcastic remarks of her in laws make her depressed. Meena consoled her and suggest her to consult doctor. After examination of reproductive systems of Sunita and her husband, doctor found no abnormalities except low sperm count of her husband and he suggested that test tube baby technique can help in fulfilling their desire of having a child.
    Read the above passage and answer the following questions:
    (i)   What are test tube babies?
    (ii)  What is artificial insemination?
    (iii) What are the possible causes of low sperm counts?
    (iv) Is it right always to blame female for not bearing child? 

  • 4)

    Chandni and her parents were watching a TV serial in the evening. During a commercial break, an advertisement flashed on the screen which was promoting use of sanitary napkins. Chandini was still watching the TV. The parents got embarrassed and changed the channel. Chandni objected to her parent's behaviour and explained the need for such advertisement. The parents understood Chandni's advice.
    (i) Briefly describe phases of a menstrual cycle.
    (ii) What is first menstruation called? When does it begin?
    (iii) What is menopause?
    (iv) What values did the parents show?

  • 5)

    The Biology teacher was taking his class and explaining the human reproductive system. Ishita in the class was busy in doing the work of some other subject and so couldn't pay any attention to her teacher and therefore missed the topic. When her teacher asked the question of what he taught she was unable to answer. She however realized her mistake, felt sorry for it and requested the teacher to explain the topic once again. The teacher readily repeated and summarised the topic.
    (i) What is the primary sex organ in male?
    (ii) What is tunica albuginea?
    (iii) Name the three tissue layers in uterus.
    (iv) Identify the values shown by the teacher.

CBSE 12th Standard Biology Subject Human Reproduction Value Based Questions 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Ramesh got a job in Mumbai but his family was still living in the village. One day, he received a letter from his father stating that he is planning marriage of her sister who will be fifteen years old in March. Ramesh did not like the idea of his father of arranging plan of his sister till she attains age of 18 years.
    Read the above passage and answer the following questions:
    (i) In your opinion, who is right Ramesh or his Father?
    (ii) What is the right age of marriage for girls?
    (iii) What are the risks involved in early marriage?

  • 2)

    Roma is working woman and gave birth to a baby two weeks ago. Due to very hectic schedule, she asked her mother-in-law to feed the powdered milk to the baby. On the other hand, mother-in-law insisted on breastfeeding.
    Read the above passage and answer the following questions:
    (i) In your opinion who is the right Roma or her mother-in-law?
    (ii) Why is breastfeeding important?
    (iii) What health problem can mother face in case she does nor breastfeed the baby?

  • 3)

    Purnima visited her native village with her grandmother. In the village, she saw some ladies, even pregnant, were smoking bidies. She also saw a child cleft palate in the lap of one of the returns home. On the way, she told Dadaji that she is planning to start campaign to make these illiterate women aware about ill effects of tobacco on health.
    Read the above passage and answer the following questions:
    (i)   Is there any harmful effect of use of tobacco smoking on our health?
    (ii)  Explain briefly the effects of smoking on human health?
    (iii) What is the effects of tobacco on next generation?

  • 4)

    Meena was shopping wth her children in the market where she met her friend Sunita after many years. During talks, Meena asked the reason of her sadness. Sunita told that even after three years of marriage she is not able to bear child and sarcastic remarks of her in laws make her depressed. Meena consoled her and suggest her to consult doctor. After examination of reproductive systems of Sunita and her husband, doctor found no abnormalities except low sperm count of her husband and he suggested that test tube baby technique can help in fulfilling their desire of having a child.
    Read the above passage and answer the following questions:
    (i)   What are test tube babies?
    (ii)  What is artificial insemination?
    (iii) What are the possible causes of low sperm counts?
    (iv) Is it right always to blame female for not bearing child? 

  • 5)

    Nisha's grandmother often blames her mother for giving birth to 3 daughters and no son and therefore wants another marriage of her son. Answer following questions on the basis of above information.
    (i) Is it right to blame a female for determination of sex and giving birth to only girls? Justify.
    (ii) What values are not exhibited by Nisha's grandmother.

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants Value Based Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Kanchan went to a garden and saw some flower which were closed.She assumed that those flowers must be buds.But she was astonished to see that all the flower were closed and neither of them were open.
    She was confused and asked her queries to her teacher.
    (i)What do you think,are there any plants with closer flower?Give an example
    (ii)Are such plants pollinated?Explain.
    (iii)What are such flowers/plants called?
    (iv)What values are shown by Kanchan?

  • 2)

    Sheela went to the garden and saw that some flowers of a plant were not open but they were closed. She thought that these flowers must be in their bud stage and will open after some time. But she was surprised to see that all the flowers of that plant were closed and move of them opened. She was at a loss to understand it and therefore asked her teacher about it. Answer the following questions:
    (i) Are there some plants which bear flowers that never open? Give example.
    (ii) What are such flowers called?
    (iii) How are such plants pollinated? Explain.
    (iv) What values are exhibited by Sheela?

  • 3)

    Once Mohan took his friend to his grandfather's orchard. There at some places they saw that some of the flowers were covered with polybags and tied. They started wondering to see it and asked the caretaker as to why it had been done. The care taker told them about the technique of artificial hybridization.
    (i) Why is artificial hybridization done?
    (ii) Why are the flowers covered with polybags ?
    (iii) What values were exhibited by the caretaker, Mohan and his friend?

  • 4)

    Neha goes to her native place in Kerala. She sees number of banana trees in her house garden. But she was surprised to see no seeds anywhere.
    (i)How does a plant of banana grow without seed?
    (ii) Is there any difference in the nutritional value?

  • 5)

    Rohan saw Mr. Sharma collecting different plant specimens. He was confused to see him doing this collection and approached him asking about it.
    Mr. Sharma told him that he will cross different plant specimens in his laboratory for obtaining better varieties of plants.
    (i) Why is he interested in such experiments?
    (ii) Name this technique.
    (iii) What precautions he should take while applying this technique?
    (iv) What values are shown by Rohan?

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants Value Based Questions 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Kanchan went to a garden and saw some flower which were closed.She assumed that those flowers must be buds.But she was astonished to see that all the flower were closed and neither of them were open.
    She was confused and asked her queries to her teacher.
    (i)What do you think,are there any plants with closer flower?Give an example
    (ii)Are such plants pollinated?Explain.
    (iii)What are such flowers/plants called?
    (iv)What values are shown by Kanchan?

  • 2)

    Ram saw a farmer spraying some chemicals on flower.On asking farmer, he came to know that this act will lead to the formation of fruits developed in this way are not good to eat as chemicals are sprayed on it.
    Next day,he asked his biology teacher about it,who explained him everything.
    (i)Were hat chemicals sprayed by the farmer?
    (ii)give difference between such a spray and usual pesticide spray?
    (iii)What is parthenocarpy?Give its types
    (iv)What values are shown by Ram?

  • 3)

    Sheela went to the garden and saw that some flowers of a plant were not open but they were closed. She thought that these flowers must be in their bud stage and will open after some time. But she was surprised to see that all the flowers of that plant were closed and move of them opened. She was at a loss to understand it and therefore asked her teacher about it. Answer the following questions:
    (i) Are there some plants which bear flowers that never open? Give example.
    (ii) What are such flowers called?
    (iii) How are such plants pollinated? Explain.
    (iv) What values are exhibited by Sheela?

  • 4)

    Once Mohan took his friend to his grandfather's orchard. There at some places they saw that some of the flowers were covered with polybags and tied. They started wondering to see it and asked the caretaker as to why it had been done. The care taker told them about the technique of artificial hybridization.
    (i) Why is artificial hybridization done?
    (ii) Why are the flowers covered with polybags ?
    (iii) What values were exhibited by the caretaker, Mohan and his friend?

  • 5)

    Neha goes to her native place in Kerala. She sees number of banana trees in her house garden. But she was surprised to see no seeds anywhere.
    (i)How does a plant of banana grow without seed?
    (ii) Is there any difference in the nutritional value?

CBSE 12th Standard Biology Subject Reproduction in Organisms Value Based Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    One day, Ramesh was standing in the kitchen with his mother who was cutting onions for making vegetable. He observed that in some of the onion bulbs, green leaves appeared on the upper end and roots on the lower end. In the evening, he shared his observation with his father, a Botany teacher. His father explained that in case of onion. new plants develop through sexual reproduction.
    Read the above passage and answer the following question:
    (i)   What is the name of this type of propagation?
    (II)  Can this method be used for raising onion plants at home also?
    (iii) Name some other vegetable which are propagated by using bulbs?
    (iv) What value is displayed by Ramesh's father?

  • 2)

    Rachna's father went to Kolkata where he was gifted a pot with new variety of rose. The flowers were very beautiful. On birthday of Rachna's father to bring for her the same variety of rose on his next visit to Kolkata. He smiled and advised her to raise it herself from the plants growing in his home.
    Read the above passage and answer the following question:
    (i)   How can father's advice help Neena to raise new seedling of rose variety present in Ranchna's home?
    (ii)  Which method of reproduction is involved in this process?
    (iii) Can this technique be used for commercial propagation of other ornamental plants?

  • 3)

    Last year, Dadaji was going to meet his old friend in a village near Lucknow. Dadaji's friend was earnings a lot by exporting mangoes. Anil also accompanied Dadaji as he also very found of mangoes. Dadaji's friend invited him to visit the orchard. Anil knew that there are many varieties of mangoes with different shapes, color of skin and tastes. On visiting the orchard, Anil was surprised to see that more than one type of mangoes were growing on the same tree.
    (i) Is it possible for Anil to grow for commercial purpose any variety of mango on the tree of mango growing in his garden?
    (ii) What type of reproduction is involved in this process?
    (iii) Name any other species which can be propagated by this technique for commercial purpose.
    (iv) How could Dadaji's friend improve the varieties of mangoes in his garden?

  • 4)

    On a biological excursion, Abhishek asked his teacher that in nature, we find that some organisms live for few weeks to few months, whereas some live for many years.
    (i) What is the term used for the certain period of time an organism lives?
    (ii) Is there any correlation between the time period for which an organism lives and their size?
    (iii) Why a rice plant lives for 3-4 months, while a banyan tree lives for 200 years? (iv) Identify the values shown by Abhishek.

  • 5)

    Sapna's younger brother saw a banana tree in backyard of a house. He could see the fruits but .no seeds.
    He wanted to know how a new plant will be produced without seed and asked Sapna (a class XII biology student) about it. She explained that some plants can grow without seeds and the phenomenon is called vegetative propagation. Her brother was amazed to know the new concept about plants.
    (i) How does banana produce a new plant? Is this reproduction, sexual or asexual?
    (ii) Give examples of some other fruits and vegetables that can reproduce by this method.
    (iii) Identify the values shown by Sapna's brother.

CBSE 12th Standard Biology Subject Reproduction in Organisms Value Based Questions 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    One day, Ramesh was standing in the kitchen with his mother who was cutting onions for making vegetable. He observed that in some of the onion bulbs, green leaves appeared on the upper end and roots on the lower end. In the evening, he shared his observation with his father, a Botany teacher. His father explained that in case of onion. new plants develop through sexual reproduction.
    Read the above passage and answer the following question:
    (i)   What is the name of this type of propagation?
    (II)  Can this method be used for raising onion plants at home also?
    (iii) Name some other vegetable which are propagated by using bulbs?
    (iv) What value is displayed by Ramesh's father?

  • 2)

    Last year, Dadaji was going to meet his old friend in a village near Lucknow. Dadaji's friend was earnings a lot by exporting mangoes. Anil also accompanied Dadaji as he also very found of mangoes. Dadaji's friend invited him to visit the orchard. Anil knew that there are many varieties of mangoes with different shapes, color of skin and tastes. On visiting the orchard, Anil was surprised to see that more than one type of mangoes were growing on the same tree.
    (i) Is it possible for Anil to grow for commercial purpose any variety of mango on the tree of mango growing in his garden?
    (ii) What type of reproduction is involved in this process?
    (iii) Name any other species which can be propagated by this technique for commercial purpose.
    (iv) How could Dadaji's friend improve the varieties of mangoes in his garden?

  • 3)

    On a biological excursion, Abhishek asked his teacher that in nature, we find that some organisms live for few weeks to few months, whereas some live for many years.
    (i) What is the term used for the certain period of time an organism lives?
    (ii) Is there any correlation between the time period for which an organism lives and their size?
    (iii) Why a rice plant lives for 3-4 months, while a banyan tree lives for 200 years? (iv) Identify the values shown by Abhishek.

  • 4)

    Sapna's younger brother saw a banana tree in backyard of a house. He could see the fruits but .no seeds.
    He wanted to know how a new plant will be produced without seed and asked Sapna (a class XII biology student) about it. She explained that some plants can grow without seeds and the phenomenon is called vegetative propagation. Her brother was amazed to know the new concept about plants.
    (i) How does banana produce a new plant? Is this reproduction, sexual or asexual?
    (ii) Give examples of some other fruits and vegetables that can reproduce by this method.
    (iii) Identify the values shown by Sapna's brother.

  • 5)

    During a visit to a park, Rita observed the bird with eggs in a nest. Suddenly, a thought came in her mind about eggs being produced in large number throughout the year in a poultry farm. She was confused and consulted her teacher that why do birds lay eggs seasonally while it is not the same case in a poultry farm. The teacher was impressed with her observation and explained the difference.
    (i) Give reason for this observation.
    (ii) What is the difference among organisms that lay eggs and those who give birth to young ones? Explain.
    (iii) What are the values shown by Rita?

CBSE 12th Standard Biology Subject Value Based Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Some parents wrote a complaint letter to the local municipality to remove all the hoardings in the city, advertising the use of condoms and matters relating to AIDS prevention. The children of these parents came to know about the matter and raised their voice against the removal of the hoardings. The parents were convinced by the awareness level of their children and withdrew the complaint.
    (i) Parents considered the hoarding as inappropriate. Do you agree/disagree with their view?
    (ii) What are the methods by which AIDS spreads?
    (iii) What is AIDS?
    (iv) What values are promoted by the children protesting against their parents?

  • 2)

    Avinash went to his village during his summer vacations. One day, he decided to visit the nearby forest and asked his grandfather to accompany him. His grandfather told him about the recent cutting of forest and the new factory which had been established. Hearing this Avinash became curious and explained his grandfather about the ecosystem services.
    (i) What are the benefits of healthy forest ecosystem?
    (ii) Explain the contribution of Robert Constanza in ecosystem services.
    (iii) What factors account for cost of various ecosystem services?
    (iv) What values are shown by Avinash?

  • 3)

    The biology teacher was explaining about restriction enzymes and came to a point explaining that these enzymes are extracted from bacteria and are called as molecular scissors. Varun, a student got curious and asked some questions for more clarity on the concept to his teacher.
    (i) From which part of microorganisms are restriction enzymes derived?
    (ii) Why are restriction enzymes called molecular scissors?
    (iii) What if some strands are needed to be cut from within. would that lead to wastage of DNA?
    (iv) What value are shown by varun?

  • 4)

    Arun visited his grandfather's farm and noticed that one of the workers was introducing earthworms in the soil. He quickly rushed to his grandfather and asked him the reason. His grandfather explained him the advantages of earthworm in soil improvement.
    (i) Why are earthworms also known as detritivores?
    (ii) Explain fragmentation.
    (iii) Name the steps in the process ofdecomposition.
    (iv) What values are shown by Arun?

  • 5)

    During a visit to Vaishno Devi, Rahul came across a young couple staying in the adjacent room in the hotel.
    He learned that the couple had been visiting different temples and performing rituals to get a child. Rahul was astonished and explained to them about ART which he had recently studied in biology. The couple were happy and understood their wrong approach and thanked Rahul.
    (i) What is ART? What is the various method included in ART?
    (ii) What are the limitations for which ART is not commonly accepted?
    (iii) Identify the values which Rahul showed.

CBSE 12th Standard Biology Subject Value Based Questions 5 Marks Questions 2021 Part - II - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    One day, while remembering about earlier time, Monu's grandfather told him that the country has made tremendous progress in the field of food grain production after green revolution. He further told that earlier we used to import wheat from other countries to feed the huge population.
    (i) What is green revolution?
    (ii) How was it achieved?
    (iii) What value is displayed by grandfather?

  • 2)

    Anil got selected in Indian Forest Service examination and was asked to appear before medical board to check his medical fitness for this service.On examination, doctor found him suffering from colour blindness.Knowing this, he consulted his family doctor to know about the reason when none of his family members was so. Doctor explained that it is due to sex linked inheritance.
    (i) What is colour blindness?
    (ii) What is sex linked inheritance?
    (iii) As a student of biology, what would you suggest to Anil so that his children are not colour blind?

  • 3)

    Priya's aunt gave birth to a child with cleft palate. Being a student of biology, Priya was curious to know the reason for this abnormality. So, she discussed this matter with her biology teacher. Teacher explained to her that it is a genetic disorder which is due to the defect in one of the chromosomes of the child.
    (i) What are genetic disorders?
    (ii) What are the possible causes of genetic disorders?
    (iii) As a student of biology, how would you create awareness in society about these disorders?

  • 4)

    Grandfather advised his grandson Manoj that he must his wash his hands before meals and he always followed his advice. This habit helped in protecting him from a number of infectious diseases. In contrast, his friend seldom bothered to wash his stands and frequently suffered from one or the other disease and therefore, was very weak physically as well as in studies.
    Read the above passage and answer the following questions:
    (i) What happens when we wash our hands?
    (ii) Name two diseases from which you can get protection by washing hands?
    (iii) What values are displayed by grandfather?

  • 5)

    After consuming sugarcane juice from a roadside vendor, Monu suffered from cough. His mother advised him to cover his nose while coughting and sneezing.
    Read the above passage and answer the following questions:
    (i) Why did Monu fall ill?
    (ii) Why did his mother advise him to cover his nose while coughting and snazing?

CBSE 12th Standard Biology Subject Value Based Questions 5 Marks Questions 2021 Part - I - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    The total human population is over 6 billion.Population of India is 1.21 billion.The number of individuals inhabiting per unit area is known as population density.Population density of India was in\(178/{ km }^{ 2 }\) 1971, \(216/{ km }^{ 2 }\) in 1971. Bangladesh, Japan, and Netherland are the most thickly populated countries with density of population being in\(617/{ km }^{ 2 }\) Bangladesh and in \(319/{ km }^{ 2 }\) Netherland.
    Answer the questions:
    (i) What are consequences of overpopulation in India?
    (ii) List any three measure to avoid pregnancy.
    (iii) What are side-effects of use of steroidal pills as contraceptive?

  • 2)

    One day, Monu did not go to school as he was not feeling well and on listening the sound of door bell he opened the door and saw two health workers at his doorstep. These health workers asked whether there was may any child of less than five years in his so that they could give him polio drops. He replied in affirmative and called his younger brother. They asked him to open his mouth and put two drops in his mouth from a vial. His neighbour, however, hid his child from health workers.
    Read the above passage and answer the following questions:
    (i)  Who took the right decision Monu or his neighbour?
    (ii)  What was the need of giving polio drops?
    (iii) What other vaccines are given to newborn?

  • 3)

    Amit observed that the children of labourers, working at the construction site of his new house, were not having proper clothes and malnourished. He asked sympathetically to one of the labourers the reason of possible condition of their children. Labourer told him that he does not earn enough to fulfil the needs of his family. Amit suggested that although he can not increase his income but he can control his family size by using birth control techniques and advised him to go to the nearest primary health centre where such devices are freely available.
    Read the above passage and answer the following questions:
    (i)  What value is displayed by Amit?
    (ii)  What are the methods available for birth control?
    (iii)  What is the additional advantage of using condom?

  • 4)

    Ravi saw that in the city at several places banners were displayed advising people to visit Red Ribbon Express Train standing at railway station of his city. He became curious and reached station. There, he came to know that the train was there to spread awareness about AIDS.
    Read the above passage and answer the following questions:
    (i)  What is AIDS?
    (ii)  What are the methods to stop the spread of AIDS?
    (iii) What are the misconceptions about AIDS?
    (iv)  What value is displayed by Ravi?

  • 5)

    One day, Ramesh was standing in the kitchen with his mother who was cutting onions for making vegetable. He observed that in some of the onion bulbs, green leaves appeared on the upper end and roots on the lower end. In the evening, he shared his observation with his father, a Botany teacher. His father explained that in case of onion. new plants develop through sexual reproduction.
    Read the above passage and answer the following question:
    (i)   What is the name of this type of propagation?
    (II)  Can this method be used for raising onion plants at home also?
    (iii) Name some other vegetable which are propagated by using bulbs?
    (iv) What value is displayed by Ramesh's father?

CBSE 12th Standard Biology Subject Value Based Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Differentiate between inbreeding and out breeding in cattle. State on eadvantage and on edisadvantage for each one of them.

  • 2)

    Expand MOET. Explain the procedure of this  technology in cattle improvement.

  • 3)

    A little child girl, Ruchika of five years had curiosity, asked her mother.Why did not she possess the moustaches and beard like her daddy.
    (i) Name the hormone responsible for the development of moustaches and beard.
    (ii) Name the cells and their location which secrete this hormone.
    (iii) Name the cells and their location which secrete the hormone responsible for the development of female characteristics in a female.Are there additional structures in the female reproductive system which secrete hormones? Name them. 

  • 4)

    A mother is ready to feed her newborn baby just after parturition by nature.
    (i) Name the cells which secrete milk.
    (ii) Name the process of producing during the first few days, after parturition.
    (iv) Name the hormone meant for release of milk.
    (v) Why the doctors recommend breastfeeding during the initial period of infant growth?

  • 5)

    Pollution is an undesirable change in physical, chemical and biological characteristics of environment, air, water, soil and land that has potential to adversely affect human life, the lives of the desirable species, natural resources, industrial processes and cultural assets.
    Given below are the sources of pollution and their effects. Using this information fill the spaces in the given box. Each pollutant may have more than one source and may show more than one effect.
    Pollutant source: Automobile exhaust, burning of fossils, refrigerant, agricultural field, fire extinguisher, paint solvents, deforestation, plastic foam.
    Effect: Photochemical smog, acid deposition, global warming, depletion of ozone.

    Name of pollutant Source Effect
    Chlorofluoro carbon (CFC) \(a\) \(p\)
    Suspended particulate matter (SPM) \(b\) \(q\)
    Oxides of nitrogen \(({ NO }_{ 2 })\) \(c\) \(r\)
    Sulphur dioxide \(({ SO }_{ 2 })\) \(d\) \(s\)
    Methane \(({ CH }_{ 4 })\) \(e\) t

CBSE 12th Standard Biology Subject Value Based Questions 3 Marks Questions 2021 Part - II - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Differentiate between inbreeding and out breeding in cattle. State on eadvantage and on edisadvantage for each one of them.

  • 2)

    Expand MOET. Explain the procedure of this  technology in cattle improvement.

  • 3)

    A joint large family living in small house face many problems.
    (i) Suggest a few measures to check over-population.
    (ii) Suggest any three propaganda campaign for restricting population control measures highlighting the safety of the persons.

  • 4)

    A little child girl, Ruchika of five years had curiosity, asked her mother.Why did not she possess the moustaches and beard like her daddy.
    (i) Name the hormone responsible for the development of moustaches and beard.
    (ii) Name the cells and their location which secrete this hormone.
    (iii) Name the cells and their location which secrete the hormone responsible for the development of female characteristics in a female.Are there additional structures in the female reproductive system which secrete hormones? Name them. 

  • 5)

    A mother is ready to feed her newborn baby just after parturition by nature.
    (i) Name the cells which secrete milk.
    (ii) Name the process of producing during the first few days, after parturition.
    (iv) Name the hormone meant for release of milk.
    (v) Why the doctors recommend breastfeeding during the initial period of infant growth?

CBSE 12th Standard Biology Subject Value Based Questions 3 Marks Questions 2021 Part - I - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    Differentiate between inbreeding and out breeding in cattle. State on eadvantage and on edisadvantage for each one of them.

  • 2)

    Expand MOET. Explain the procedure of this  technology in cattle improvement.

  • 3)

    A joint large family living in small house face many problems.
    (i) Suggest a few measures to check over-population.
    (ii) Suggest any three propaganda campaign for restricting population control measures highlighting the safety of the persons.

  • 4)

    A little child girl, Ruchika of five years had curiosity, asked her mother.Why did not she possess the moustaches and beard like her daddy.
    (i) Name the hormone responsible for the development of moustaches and beard.
    (ii) Name the cells and their location which secrete this hormone.
    (iii) Name the cells and their location which secrete the hormone responsible for the development of female characteristics in a female.Are there additional structures in the female reproductive system which secrete hormones? Name them. 

  • 5)

    A mother is ready to feed her newborn baby just after parturition by nature.
    (i) Name the cells which secrete milk.
    (ii) Name the process of producing during the first few days, after parturition.
    (iv) Name the hormone meant for release of milk.
    (v) Why the doctors recommend breastfeeding during the initial period of infant growth?

CBSE 12th Standard Biology Subject Value Based Questions 2 Marks Questions With Solution - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    (i) Name two genetically engineered recombinant proteins used for treatement of specific disorders.
    (ii) Name a substance produced by certain bacteria used in blood transfusion.
    (iii) Who is credited with synthesis og gene.

  • 2)

    In the daily Tribune dt. August 20, 2012 there was a news under heading 'New Stem Cell treatement to cure cancer'. Professor Revenue head of bone marrow transplantation at Israel's Hadassah' Medical Centre in Jerusalem said: The technique uses specialised harvested cells to produce infection - fighting bone marrow. Patients with blood cancers have most of their bone marrow destroyed when given radiation or chemotherapy to destroy their disease.
    (i) What are stem cells?
    (ii) What is the source of stem cells?
    (iii) What are the infection - fighting cells produced by bone marrow?
    (iv) Name the diseases which can be curved by this life saving treatements.
    (v) What is the effect of bone marrow transplantation?

  • 3)

    What is interspecific hybridization? Write one example of it.

  • 4)

    Raju’s younger sister has seen a banana tree in backyard of a house. She could see the fruits but no seeds. She wants to know how a new plant of banana will be produced without seed. What will you explain to your sister?

  • 5)

    Ram is a person of age 42 years old living in a village of Assam. His house is surrounded by a number of bamboo trees but he could not see any flower on them until now. What can be the explanation of his observation? How does bamboo reproduce?

CBSE 12th Standard Biology Subject Value Based Questions 2 Marks Questions 2021 Part - II - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    (i) Name two genetically engineered recombinant proteins used for treatement of specific disorders.
    (ii) Name a substance produced by certain bacteria used in blood transfusion.
    (iii) Who is credited with synthesis og gene.

  • 2)

    Two claimant fathers filed a case against a lady claiming to be the father of her only daughter. How could this case be settled identifying the real biological father?

  • 3)

    The police department could obtain a bunch of hair from the gripped hand of a murdered man. There were two persons arrested in this criminal case. How will the forensic department, give a clue to the criminals?

  • 4)

    A man with blood group A and his wife blood group B have a son with blood group O, father claim that was not his son. How can the problem be solved?

  • 5)

    Sometimes Gene flow or Gene migration is harmful for a population why?

CBSE 12th Standard Biology Subject Value Based Questions 2 Marks Questions 2021 Part - I - by Shweta Sharma - Anantapur - May 31, 2021 - View & Read

  • 1)

    (i) Name two genetically engineered recombinant proteins used for treatement of specific disorders.
    (ii) Name a substance produced by certain bacteria used in blood transfusion.
    (iii) Who is credited with synthesis og gene.

  • 2)

    In the daily Tribune dt. August 20, 2012 there was a news under heading 'New Stem Cell treatement to cure cancer'. Professor Revenue head of bone marrow transplantation at Israel's Hadassah' Medical Centre in Jerusalem said: The technique uses specialised harvested cells to produce infection - fighting bone marrow. Patients with blood cancers have most of their bone marrow destroyed when given radiation or chemotherapy to destroy their disease.
    (i) What are stem cells?
    (ii) What is the source of stem cells?
    (iii) What are the infection - fighting cells produced by bone marrow?
    (iv) Name the diseases which can be curved by this life saving treatements.
    (v) What is the effect of bone marrow transplantation?

  • 3)

    What is interspecific hybridization? Write one example of it.

  • 4)

    Raju’s younger sister has seen a banana tree in backyard of a house. She could see the fruits but no seeds. She wants to know how a new plant of banana will be produced without seed. What will you explain to your sister?

  • 5)

    Ram is a person of age 42 years old living in a village of Assam. His house is surrounded by a number of bamboo trees but he could not see any flower on them until now. What can be the explanation of his observation? How does bamboo reproduce?

CBSE 12th Standard Biology Subject Microbes in Human Welfare HOT Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 29, 2021 - View & Read

  • 1)

    An organic farmer releies on natural predection for controlling plant pests and diseases. Justify giving reasons why this is considered to be holistic approch.

  • 2)

    Name 'A' and 'B' in the following equations:
    Sugary juice \(\underrightarrow { 'A' } \) Ethanol + H2 O ; Ethanol \(\underrightarrow { Acetobacter\quad aceti } \) B

  • 3)

    What is the role of microbes in sewage treatment plant?

  • 4)

    Name the gobar gas liberated from a biogas plant.Which type of bacteria are responsible for its production? What are the advantages of using it as a source of energy?

  • 5)

    As we are going to face a great crisis of fossil fuel in near future, suggest an eco-friendly and pollution free alternative source of energy for rural areas which is dependent on microbial activity.

CBSE 12th Standard Biology Subject Microbes in Human Welfare HOT Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 29, 2021 - View & Read

  • 1)

    What will happen if you add a small amount of curd to the fresh milk and keep it for few hours at 25oC.name the process, chemical changes and the resultant products? Name any three edible products prepared from it.

  • 2)

    Name the gobar gas liberated from a biogas plant.Which type of bacteria are responsible for its production? What are the advantages of using it as a source of energy?

  • 3)

    As we are going to face a great crisis of fossil fuel in near future, suggest an eco-friendly and pollution free alternative source of energy for rural areas which is dependent on microbial activity.

  • 4)

    Explain why some microorganisms are called biofertilizers.Give two examples.

  • 5)

    Identify the microorganism
    (i) A soil inhabiting bacteria that forms a symbiotic association with the roots of leguminous plants
    (ii) A cyanobacteria that forms a symbiotic association with an aquatic fern.
    (iii) A microbe responsible for the preparation of the dough, which is used for making bread.
    (iv) A methanogenic bacteria used in the production of biogas. 

CBSE 12th Standard Biology Subject Microbes in Human Welfare HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 29, 2021 - View & Read

  • 1)

    Why some molecules are called bioactive molecules?Give two examples of such molecules.

  • 2)

    The dough/ batter out of which Dosa and idly is made, appears to be puffed when kept for some time. What thing is responsible for the puffy appearance? Can you tell the metabolic pathway responsible for giving this puffy appearance? Also, name the microorganism involved in this process?

  • 3)

    Different variety of cheese is known by their texture, flavors and taste. A variety of cheese is having “pores” in it. State the reason behind this. Name the microbe responsible for it. Also name the variety of cheese?

  • 4)

    Water samples, three in number namely river water; sewage water and secondary effluent from STP were subjected to BOD test. They were labeled A B & C but the laboratory technician did not note which was which. The BOD values of three samples A, B & C were recorded as 30mg/l, 8mg/l and 500mg/l respectively. Which sample of water is most polluted? Can you assign the correct label to each assuming the river water relatively clear?

  • 5)

    A white coloured, dry powdered substances is sprayed on the vulnerable plants to control butterfly caterpillars. Guess what thing of biological origin may be there in. What is the source /micro-organism of it?

CBSE 12th Standard Biology Subject Microbes in Human Welfare HOT Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 29, 2021 - View & Read

  • 1)

    How was penicillin discovered?

  • 2)

    Why some molecules are called bioactive molecules?Give two examples of such molecules.

  • 3)

    The dough/ batter out of which Dosa and idly is made, appears to be puffed when kept for some time. What thing is responsible for the puffy appearance? Can you tell the metabolic pathway responsible for giving this puffy appearance? Also, name the microorganism involved in this process?

  • 4)

    Radha had just undergone a kidney transplant A bioactive molecular drug in administered to oppose kidney rejection by the body. What is the bioactive molecule? Also name the microbe from which this is extracted?

  • 5)

    A patient who has been suffering from myocardial infarction is found to be having clots in the blood vessels. “Clot Buster” is used to dissolve the clots. Name the clot buster used to digest the clot and the micro-organism from which it is extracted also?

CBSE 12th Standard Biology Subject Microbes in Human Welfare HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why do we prefer to call secondary wastewater treatment as biological treatment?

  • 2)

    What would have happened if antibiotics were not discovered?

  • 3)

    How do statins reduce the blood cholesterol level?

  • 4)

    Explain the consequence if the oxygen availability to activated sludge flocs is reduced.

  • 5)

    Two villagers were arguing for the nutritive value of milk and curd? Being a normal science student and having studied the biochemistry of both the products, tell which one is more nutritive and justify it ?

CBSE 12th Standard Biology Subject Microbes in Human Welfare HOT Questions 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why do we prefer to call secondary wastewater treatment as biological treatment?

  • 2)

    What would have happened if antibiotics were not discovered?

  • 3)

    Why is cow dung used in the generation of biogas?

  • 4)

    What would happen if our intestine harbors microbial flora exactly similar to that found in the rumen of cattle?

  • 5)

    Citric acid is available in the market and acts as an excellent food preservative, can you name the microorganism out of which it is extracted?

CBSE 12th Standard Biology Subject Environmental Issues HOT Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    (i) The graph given alongside represent the growth patterns of two types of aquatic organisms over a brief period of times in a water body surrounded by an agricultural land extensively supplied with fertilisers.Identify the organisms that would represent (i) A and (ii) B.
    (ii) State the reason for such a change in the water body and also write the term given to it.

  • 2)

    In the pie charts (A) and (B) drawn below to show the global animal diversity, which groups of animals would you name and write on the area shaded black in (A) and (B). In which kind of habitat would you find these groups of animals?
       

  • 3)

    How is the 'sixth episode of extinction' of species on earth, now currently in progress, different from the five earlier episodes? What is it due to? Explain the various causes that have brought about this difference.

  • 4)

    (a) What are hot spots of biodiversity?
    (b) List four main criteria for determining a particular place as a hot spot.
    (c) Among the hot spots of the world, list two which are located in India.

  • 5)

    From among plants, invertebrates and vertebrates, list respectively those taxa which occur maximum in numbers at present.

CBSE 12th Standard Biology Subject Environmental Issues HOT Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Given below are pie diagrams A, B and C related to proportionate number of species of major taxa of invertebrates, vertebrates and plants respectively. Critically study and fill in the blanks (a), (b),(c) and (d).

  • 2)

    (a) What are hot spots of biodiversity?
    (b) List four main criteria for determining a particular place as a hot spot.
    (c) Among the hot spots of the world, list two which are located in India.

  • 3)

    From among plants, invertebrates and vertebrates, list respectively those taxa which occur maximum in numbers at present.

  • 4)

    The use of incinerators is crucial for the disposal of hospital waste justify.

  • 5)

    Why does deforestation lead to global warming?

CBSE 12th Standard Biology Subject Environmental Issues HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    How do religious beliefs help in the conservation of biodiversity?

  • 2)

    Why are grains and vegetables produced in organic farms supposed to be better for human consumption than those produced in farms where chemical fertilizers, pesticides etc. has been used?

  • 3)

    Why is organic farming considered more eco –friendly than agro-chemical farming?

  • 4)

    There are reports that the size of Arctic ice cap is decreasing every year.
    a) What are its possible reasons?
    b) How we the human beings are responsible to a greater extent for this?
    c) How we can contribute to check this trend?

  • 5)

    In a survey it is observed that the population of fish-eating birds living on the bank of lake is continuously declining, where DDT is regularly sprayed to check mosquitoes.
    i) What could be the reason behind this?
    ii) Name the phenomenon involved.

CBSE 12th Standard Biology Subject Environmental Issues HOT Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Study the given aquatic food chain and answer the questions that follow:

    (i) Give reasons why there is a continuous increase in the DDT content in different trophic levels of the chain.
    (ii) Name the phenomenon responsible for the increase in DDT content.

  • 2)

    During last few decades, most products are being sold in secure ‘consumer friendly’packages .
    a) Should this be encouraged?
    b) How are modern packaging techniques turning into a major environmental threat?
    c) Give some examples where such packaging can be easily avoided.

  • 3)

    Why are grains and vegetables produced in organic farms supposed to be better for human consumption than those produced in farms where chemical fertilizers, pesticides etc. has been used?

  • 4)

    (a) What will happen if electrode wires are not maintained at several thousand volts?
    (b) The velocity of air is high

  • 5)

    In a survey it is observed that the population of fish-eating birds living on the bank of lake is continuously declining, where DDT is regularly sprayed to check mosquitoes.
    i) What could be the reason behind this?
    ii) Name the phenomenon involved.

CBSE 12th Standard Biology Subject Environmental Issues HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    What photochemical oxidant pollute air?

  • 2)

    Why Western Ghats in India have been declared as biological hot spots?

  • 3)

    Regions with high endemism are chosen as hot spots. Why?

  • 4)

    Through auto fuel policy, Euro II norms, the government of india has laid out a road map to cut down the vehicular air pollution in many cities of india.what this norms stipulated?

  • 5)

    Why does deforestation lead to loss of biodiversity?

CBSE 12th Standard Biology Subject Environmental Issues HOT Questions 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    What photochemical oxidant pollute air?

  • 2)

    Why Western Ghats in India have been declared as biological hot spots?

  • 3)

    Regions with high endemism are chosen as hot spots. Why?

  • 4)

    Through auto fuel policy, Euro II norms, the government of india has laid out a road map to cut down the vehicular air pollution in many cities of india.what this norms stipulated?

  • 5)

    Why does deforestation lead to loss of biodiversity?

CBSE 12th Standard Biology Subject Biotechnology: Principles and Processes HOT Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Give an example of a natural form of genetic engineering in which the bacterium inserts gene into plants to cause gall or tumour formation.

  • 2)

    Do you see the prospects of viroids being used as plant vectors in near future?

  • 3)

    Give an example where a disease causing pathogen of animals has been transformed into useful vector for delevering genes to humans.

  • 4)

    Write the name of genus, species, strain of source bacteria from which the following endonucleases are obtained. Also write the order of their identification in the bacteria.
    (i) Eco R I
    (ii) Hind II

  • 5)

    Youn have been given a task to break the cells of following organisms and release DNA along with other macromolecules from them. Name the specific enzymes you will select for the task:
    (i) Bacterial cell
    (ii) Plant cell
    (iii) Fungal cell

CBSE 12th Standard Biology Subject Biotechnology: Principles and Processes HOT Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Give an example of a natural form of genetic engineering in which the bacterium inserts gene into plants to cause gall or tumour formation.

  • 2)

    Do you see the prospects of viroids being used as plant vectors in near future?

  • 3)

    Name the method/s by which the transgenic sheeps and goats are made. What are other methods?

  • 4)

    What will happen if -
    (i) A plasmid vector is digested with Eco RI at a single site
    (ii) A sample of human DNA is digested with Eco RI.
    (iii) The two samples (plasmid and human DNA) are allowed to hybridise in presence of DNA ligase.

  • 5)

    Youn have been given a task to break the cells of following organisms and release DNA along with other macromolecules from them. Name the specific enzymes you will select for the task:
    (i) Bacterial cell
    (ii) Plant cell
    (iii) Fungal cell

CBSE 12th Standard Biology Subject Biotechnology: Principles and Processes HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    A and B are two different cloning vectors in two different bacterial colonies cultured in chromogenic substrate Bacterial colonies with cloning vector A were colourless, whereas those with B were blue coloured. Explain by giving reasons the cause of difference in colour that appeared.

  • 2)

    A plasmid DNA and a linear DNA (both of the same size) have one site for a restriction endonuclease. When cut and separated on agarose gel electrophoresis, plasmid shows one DNA band, while the linear DNA shows two fragments. Explain.

  • 3)

    While carrying out a PCR, 'denaturation' step was missed. What will be its effect on the process?

  • 4)

    Why do prokaryotes(bacteria) have restriction enzymes but not eukaryotes?

  • 5)

    (a) A recombinant vector with a gene of interest inserted within the gene of a-galactosidase enzyme, is introduced into a bacterium. Explain the method that would help in selection of recombinant colonies from non-recombinant ones.
    (b) Why is this method of selection referred to as "insertional inactivation" ?

CBSE 12th Standard Biology Subject Biotechnology: Principles and Processes HOT Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Explain giving reaons why an alien piece of DNA needs to be integrated to a specific sequence of host DNA for its cloning.

  • 2)

    A and B are two different cloning vectors in two different bacterial colonies cultured in chromogenic substrate Bacterial colonies with cloning vector A were colourless, whereas those with B were blue coloured. Explain by giving reasons the cause of difference in colour that appeared.

  • 3)

    A plasmid DNA and a linear DNA (both of the same size) have one site for a restriction endonuclease. When cut and separated on agarose gel electrophoresis, plasmid shows one DNA band, while the linear DNA shows two fragments. Explain.

  • 4)

    An alien piece of DNA needs to be integrated to a specific sequence of host DNA for its cloning. Is it true? if yes, explain. If this is DNA is not picked up by host cells. Can you suggest a reason for it?

  • 5)

    What would happen if you grow a recombinant in a bioreactor but forget to add antibiotic to the medium in which the recombinant is growing?

CBSE 12th Standard Biology Subject Biotechnology: Principles and Processes HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why is the enzyme cellulase needed for isolating genetic material from plant cells and not from animal cells?

  • 2)

    Why is it essential to have a 'selectable marker' in a cloning vector?

  • 3)

    Restiction enzymes should not have mora than one site of action in the cloning site of a vector? Comment

  • 4)

    Would you choose an exonuclease for producing a recombinant DNA molecule?

  • 5)

    Retroviruses are disease-causing microorganisms, even then are efficiently used in biotechnology experiments. Explain how is it possible?

CBSE 12th Standard Biology Subject Biotechnology: Principles and Processes HOT Questions 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why is the enzyme cellulase needed for isolating genetic material from plant cells and not from animal cells?

  • 2)

    Why is it essential to have a 'selectable marker' in a cloning vector?

  • 3)

    Restiction enzymes should not have mora than one site of action in the cloning site of a vector? Comment

  • 4)

    Would you choose an exonuclease for producing a recombinant DNA molecule?

  • 5)

    Retroviruses are disease-causing microorganisms, even then are efficiently used in biotechnology experiments. Explain how is it possible?

CBSE 12th Standard Biology Subject Biodiversity and Conservation HOT Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    What would be the impact on the environment around a thermal power plant if its electrostatic precipitator stops functioning? Give a reason.

  • 2)

    (a) Why are people living in West Bengal prove to Black foot disease?
    (b) What is blue baby syndrome? Explain.

  • 3)

    The figure is given shows relative contributions of various greenhouse gasses to the total global warming.

    (i) Name the gasses (a) and (b)

  • 4)

    The graph below represents the growth patterns of types of aquatic organisms over a brief period of time in a water body surrounded by an agricultural land extensively supplied with fertilizers. Identify what would represent(i) A and (ii) B.

  • 5)

    Since the origin of life on earth and evolution there have been 5 episodes of mass extinction, but the current rate of extinction is 100-1000 times. What are the main causes of high extinction rate and how is it going to harm human beings?

CBSE 12th Standard Biology Subject Biodiversity and Conservation HOT Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    What would be the impact on the environment around a thermal power plant if its electrostatic precipitator stops functioning? Give a reason.

  • 2)

    Microbes play a dual role when used for sewage treatment as they not only help to retrieve usable water but also generate fuel. Write in points how this happens?

  • 3)

    What are flocs? State their role in effluent treatment and their ultimate fate in sewage treatment tank.

  • 4)

    Create an aquatic food chain in a water body into which effluents flow from a pesticide factory. Diagrammatically represent and answer the following questions:
    What is the phenomenon called?

  • 5)

    Since the origin of life on earth and evolution there have been 5 episodes of mass extinction, but the current rate of extinction is 100-1000 times. What are the main causes of high extinction rate and how is it going to harm human beings?

CBSE 12th Standard Biology Subject Biodiversity and Conservation HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Write a critical note on the following:
    (i) Hotspots of biodiversity.
    (ii) Ex-situ conservation.
    (iii) India's effort in biodiversity

  • 2)

    What is EI Nino effect? Explain how it accounts for biodiversity loss.

  • 3)

    Mention the major cause of air pollution in metro cities. Write any three ways by which it can be reduced.

  • 4)

    What is depicted by the following representation of species diversity? Why these estimates do not give any figure-for prokaryotes.

  • 5)

    Categorize the following into in-situ and ex-situ approaches of biodiversity conservation.
    i) Botanical gardens
    ii) Wild life sanctuaries
    iii) Gene bank
    iv) Biosphere reserves
    v) Sacred forests/lakes
    vi) Pollen banks
    vii) Tissue culture
    viii) Cryo-preservation

CBSE 12th Standard Biology Subject Biodiversity and Conservation HOT Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    The species diversity of plants (22 per cent) is much less than that of animals (72 per cent). What could be the explanations to how animals achieved greater diversification?

  • 2)

    Write a critical note on the following:
    (i) Hotspots of biodiversity.
    (ii) Ex-situ conservation.
    (iii) India's effort in biodiversity

  • 3)

    What is EI Nino effect? Explain how it accounts for biodiversity loss.

  • 4)

    On a log scale, species area relationship becomes linear and can be represented by equation logS = logC + z logA. What is represented by S, z,a & c in this equation. What is the average value of Z-line irrespective of the taxonomic group or the region? The z value for frugivorous birds and mammals in the tropical forests of different continents is found to be 1.15. Why is it so?

  • 5)

    Ecologists believe that communities with more species tend to be more stable than  those with less species. What attributes are taken into account while defining a stable community. Mention the observation of David Tilman ecological experiments using outdoor plots.

CBSE 12th Standard Biology Subject Biodiversity and Conservation HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    In global warming real, only a theory or speculation?

  • 2)

    Will climate change bring benefits to some areas?

  • 3)

    India is one of the twelve mega biodiversity countries Countries of the world. what are the various levels of biodiversity observed in India?

  • 4)

    India has only 2.4% of the land area of the world but it has 8.1% of the species diversity. what are the favorable environmental condition that has favoured speciation in india?

  • 5)

    20 parrots, 50 sparrows and 150 crows are found in one part of seven senses garden which has large number of trees. Which parameter- species richness or species evenness can be easily assessed from this information?

CBSE 12th Standard Biology Subject Biodiversity and Conservation HOT Questions 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    In global warming real, only a theory or speculation?

  • 2)

    Will climate change bring benefits to some areas?

  • 3)

    India has only 2.4% of the land area of the world but it has 8.1% of the species diversity. what are the favorable environmental condition that has favoured speciation in india?

  • 4)

    What is the scientific term for measurement of species diversity if (i) number of species per unit area are measured (ii) relative abundance with which each species is represented in an area is measured.

  • 5)

    20 parrots, 50 sparrows and 150 crows are found in one part of seven senses garden which has large number of trees. Which parameter- species richness or species evenness can be easily assessed from this information?

CBSE 12th Standard Biology Subject Ecosystem HOT Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Explain why ecological succession will be faster in a forest devastated by fire than on a bare rock? Also, compare succession in case of an abandoned land after floods with that on a bare rock?

  • 2)

    When is the structure and composition of a community expected to remain unchanged?

  • 3)

    Given below are two figures depicting pyramid of numbers and pyramid of biomass in aquatic ecosystem and parasitic food chain.Observe the figures carefully and fill in the blanks (a), (b), (c) and (d).

  • 4)

    Why are reducers or decomposers considered crucial and essential components of an ecosystem? Explain.

  • 5)

    Why are nutrient cyclesin nature called biogeochemical cycles?

CBSE 12th Standard Biology Subject Ecosystem HOT Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why are green algae not likely to be found in the deepest strata of the ocean?

  • 2)

    Explain why ecological succession will be faster in a forest devastated by fire than on a bare rock? Also, compare succession in case of an abandoned land after floods with that on a bare rock?

  • 3)

    In the pictures provided, what is the relationship between (1) and (2) and (3) and (4) with respect to trophic levels.

  • 4)

    In a pyramid of biomass drawn below, name the two crops:
    (i) one which is supported and
    (ii) the one which supports.In which ecosystem is such a pyramid found?

  • 5)

    Why are reducers or decomposers considered crucial and essential components of an ecosystem? Explain.

CBSE 12th Standard Biology Subject Ecosystem HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    'The energy flow in an ecosystem is unidirectional'.Justify the statement.

  • 2)

    Only 1% energy of sun is trapped by green plants and only 10% energy is transferred from one trophic level to another. Based on this data how will you justify the first law of thermodynamics?

  • 3)

    Try to Make ecological pyramid of a food web. What difficulties do you face in making it?

  • 4)

    What is the source of energy in detritus food chain? How its source of energy is different from those of GFC?

  • 5)

    A farmer observed that in a field after ploughing , the process of fragmentation of the organic material becomes very slow . What could be the reason for this and why?

CBSE 12th Standard Biology Subject Ecosystem HOT Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Try to Make ecological pyramid of a food web. What difficulties do you face in making it?

  • 2)

    A large number (about 1000) of insects are feeding on a tree, while a number of 100 small birds depend on the insects and are in turn eaten by 10 large birds. Draw an ecological pyramid. Also draw ecological pyramid of energy for the same data?

  • 3)

    Vultures feed on dead animals.  Earthworms feed on dead leaves, while Bacteria also feed on dead plants and animals. How can you differentiate the above mentioned organisms? What is the position of above mentioned organisms in a food chain?

  • 4)

    During a visit, students found that a forest has been destroyed totally by fire.The students asked their teacher, “Can the forest grow here again?” The teacher explained,” Yes, of course. Even a bare rock in course of time can also convert into a forest.  Growth of forest  on a bare rock is known as primary succession while community developed in the burnt forest is known secondary succession."
    i) In your opinion, where will be the growth of community faster the burnt forest or the bare rock? Why?
    ii) Why on bare rock succession is called primary while in a burnt forest, succession is secondary?

  • 5)

    From thousands of years, balance was maintained between the amount of CO2 and O2 in the atmosphere. But recently it has been observed that amount of CO2 has increased than normal?
    i) What is the reason for it?
    ii) What will be its possible effect on life on earth?

CBSE 12th Standard Biology Subject Ecosystem HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Which of the following is a free living bacteria that can fix nitogen in the soil?
    Spirulina, Azospirillum, Sonalika

  • 2)

    Which of the following is a cyanobacterium that can fix atmospheric nitrogen?
    Azospirillum, Oscillatoria, Sonalika

  • 3)

    'GPP-R=NPP'what do you understand by the given equation?

  • 4)

    What are eco system service? Why Robert Constanza Put a price tags on nature's life- support services?

  • 5)

    Explain Hydrarch succession in detail. How it is different from Xerarch succession?

CBSE 12th Standard Biology Subject Ecosystem HOT Questions 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    'Ecosystem is called an interactive system'.Name a functional aspect of the ecosystem which justifies the above statement.

  • 2)

    'Stability of ecosystem debens on complexity of food web. 'Justify the statement. 

  • 3)

    'GPP-R=NPP'what do you understand by the given equation?

  • 4)

    What are eco system service? Why Robert Constanza Put a price tags on nature's life- support services?

  • 5)

    Differentiate between – (a) Primary and Secondary succession
    (b) Pyramid of energy and Pyramid of biomass.

CBSE 12th Standard Biology Subject Organisms and Populations HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    In an association of two animal species, one is a termite which feeds on wood and the other is a protozoan Trichonympha present in the gut of the termite. What type of association they establish?

  • 2)

    An orchid plant is growing on the branch of mango tree. How do you describe this interaction between the orchid and the mango tree?

  • 3)

    Flowers have different adaptations for pollination (essential for reproduction), one of them being colour. But night blooming flowers are generally white in colour. Why?

  • 4)

    A person working in office try to perform his/ her level best at normal room temperature and also wishes to maintain it by using AC, or fans or heaters. But a labourer works well even under adverse climatic condition. How could his body do it?

  • 5)

    Some living organisms respond to external environment by changing their morphplogy or physiology or behavioral pattern. What is the terminology for this? How the desert animal like kangaroo rat is capable of meeting all its water requirements?

CBSE 12th Standard Biology Subject Organisms and Populations HOT Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    An orchid plant is growing on the branch of mango tree. How do you describe this interaction between the orchid and the mango tree?

  • 2)

    Most of the living organisms try to maintain the constancy of their internal environment in terms of optimal temperature and osmotic concentration. What is the terminology used for this type of constancy. How the following organisms do maintains it and also specifies the terms for that -:
    a) Mammals
    b) All plants
    c) Birds in Siberia
    d) Bacteria, Fungi & Lower Plants

  • 3)

    Generally thermo regulation is energetically expensive for many organisms. So, many smaller animals are rarely found in extreme hot or cold climatic condition. Why? Write two specific reasons.

  • 4)

    A person working in office try to perform his/ her level best at normal room temperature and also wishes to maintain it by using AC, or fans or heaters. But a labourer works well even under adverse climatic condition. How could his body do it?

  • 5)

    Green plants prepare their food either by C3 or C4  pathway  but most of the desert plants have a special photosynthetic pathway called  CAM. What is the reason for such type of adaptation?

CBSE 12th Standard Biology Subject Organisms and Populations HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why are green plants not found beyond a certain depth in the ocean?

  • 2)

    'Green algae are not likely to be found in the deepest strata of the ocean'. Give atleast one reason.

  • 3)

    An exotic variety of prickly pear introduced in Australia turned out to be invasive. How was it brought under control?

  • 4)

    Mention how closely related species of warblers are able to co-exist in a competitive environment.

  • 5)

    When and Where will you found pseudo copulation?

CBSE 12th Standard Biology Subject Organisms and Populations HOT Questions 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Name two 'photoperiod' dependent processes, one each in plants and in animals.

  • 2)

    When and Where will you found pseudo copulation?

  • 3)

    What helps the fishes to survive in different water conditions?

  • 4)

    Explain Gause's Cometitive exlusion principle.

  • 5)

    Why have many animals not evolved thermo regulation?

CBSE 12th Standard Biology Subject Biotechnology and its Application HOT Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    (i)  A transgenic organism gives milk which has huge quantities of human protein.
    (ii) A transgenic fruit acts as edible vaccine which protects children against diarrhoea.
    (iii) A transgenic fruit has capability of producing ethylene 10% less as compared to normal slowing down the process of ripening.

  • 2)

    Explain how golden rice can prevent child blindness.

  • 3)

    Explain how transgenic animals serve as model for human diseases?

  • 4)

    In a medical case, It was detected that a child is suffering from a genetic disorder due to the deletion of the gene. What remedial measure do you suggest for the treatment of such disorder.

  • 5)

    Correct the following statement giving reasons -
    "The mature insulin molecule consists of three short polypeptide chains".

CBSE 12th Standard Biology Subject Biotechnology and its Application HOT Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    (i)  A transgenic organism gives milk which has huge quantities of human protein.
    (ii) A transgenic fruit acts as edible vaccine which protects children against diarrhoea.
    (iii) A transgenic fruit has capability of producing ethylene 10% less as compared to normal slowing down the process of ripening.

  • 2)

    Explain how golden rice can prevent child blindness.

  • 3)

    Explain how transgenic animals serve as model for human diseases?

  • 4)

    In a medical case, It was detected that a child is suffering from a genetic disorder due to the deletion of the gene. What remedial measure do you suggest for the treatment of such disorder.

  • 5)

    Correct the following statement giving reasons -
    "The mature insulin molecule consists of three short polypeptide chains".

CBSE 12th Standard Biology Subject Biotechnology and its Application HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Differentiate the terms 'Cry' and 'cry'.

  • 2)

    State the consequence when Meloidegyne incognita consumes cells with RNAi gene.

  • 3)

    Name a set of principles that may be used to regulate human activities in relation to the biological world. Why they are important?

  • 4)

    Why is the functional insulin produced,considered better than the ones used earlier by diabetic patients?

  • 5)

    What will happen if some how the pH of the gut of caterpillar is sustained acidic rather than basic (alkaline) and they are subjected to carry – protein produced by Bacillus thurin giensis?

CBSE 12th Standard Biology Subject Biotechnology and its Application HOT Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Differentiate the terms 'Cry' and 'cry'.

  • 2)

    State the consequence when Meloidegyne incognita consumes cells with RNAi gene.

  • 3)

    Name a set of principles that may be used to regulate human activities in relation to the biological world. Why they are important?

  • 4)

    Why is the functional insulin produced,considered better than the ones used earlier by diabetic patients?

  • 5)

    What will happen if some how the pH of the gut of caterpillar is sustained acidic rather than basic (alkaline) and they are subjected to carry – protein produced by Bacillus thurin giensis?

CBSE 12th Standard Biology Subject Biotechnology and its Application HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    How is boitechnology useful in increased insulin production to benefit needy people?

  • 2)

    A multinational company uses the bio-resources without proper authorization from the country concerned. What is the term given to this unauthorized use?

  • 3)

    A committee has been constituted by the Indian govt. Which is meant to take decisions regarding the validity of Gm research and safety measures of introducing GMO’s for public service. Name it?

  • 4)

    Proteins encoded by genes ‘cry IAc’ and ‘cry IIAb’ and that of ‘cry IAb’are slightly different in their control.’ What is the logic behind this statement?

  • 5)

    Use of _________ is considered to be the solution by which the farmers can get maximum yield by minimum use of fertilizers and chemicals ?

CBSE 12th Standard Biology Subject Biotechnology and its Application HOT Questions 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    How is boitechnology useful in increased insulin production to benefit needy people?

  • 2)

    A multinational company uses the bio-resources without proper authorization from the country concerned. What is the term given to this unauthorized use?

  • 3)

    A committee has been constituted by the Indian govt. Which is meant to take decisions regarding the validity of Gm research and safety measures of introducing GMO’s for public service. Name it?

  • 4)

    Proteins encoded by genes ‘cry IAc’ and ‘cry IIAb’ and that of ‘cry IAb’are slightly different in their control.’ What is the logic behind this statement?

  • 5)

    Use of _________ is considered to be the solution by which the farmers can get maximum yield by minimum use of fertilizers and chemicals ?

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production HOT Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    'Plant breeding technique has helped sugar undersity in North India? Explain.

  • 2)

    What is the different between pisciculture and Aquaculture? What are the benefits of both kinds of cultures?

  • 3)

    What ingredients you suggest to be added in the following specified culture media?
    (a) Preparation of a semisolid medium
    (b) Preparation of a solid medium
    (c) A culture medium for graving an explant in vitro.

  • 4)

    What will you do to get your cow crossed artificially by an exotic bull?

  • 5)

    What is the main reason for low milk production in  India? How can it be improved?

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production HOT Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    'Plant breeding technique has helped sugar undersity in North India? Explain.

  • 2)

    Name the blank spaces a,b,c and d from the table given below

    Name of crop Hybrid variety Resistance to diseases/pests
    a Himgiri Leaf and stripe rust, hill bunt
    Mustard b Aphids
    Cowpea Pusa komal c
    Chilli Pusa Sadabahar d
  • 3)

    What ingredients you suggest to be added in the following specified culture media?
    (a) Preparation of a semisolid medium
    (b) Preparation of a solid medium
    (c) A culture medium for graving an explant in vitro.

  • 4)

    What will you do to get your cow crossed artificially by an exotic bull?

  • 5)

    What is the main reason for low milk production in  India? How can it be improved?

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why are biofortified maize and wheat considered nutritionally improved?

  • 2)

    SCP- One of the alternate source of protein for animal and human beings. Expand this term and how it could ease the pressure on agriculture and dairy farming.

  • 3)

    Fill in the blanks 1, 2, and 3.

    Name of the crop Name of the hybrid variety Resistant to
    Brassica 1 Aphids
    Flat bean Pusa sem 2
    Okera Bhindi 3 Shoot and fruit borer
  • 4)

    Besides conventional breeding technique for disease resistant  varieties,  now  a  day  a  new breeding technique is practiced. How it is advantageous over the conventional technique or what is the drawback of this technique?

  • 5)

    Why is it easier to culture meristems compared to permanent tissues?

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production HOT Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why are biofortified maize and wheat considered nutritionally improved?

  • 2)

    SCP- One of the alternate source of protein for animal and human beings. Expand this term and how it could ease the pressure on agriculture and dairy farming.

  • 3)

    Fill in the blanks 1, 2, and 3.

    Name of the crop Name of the hybrid variety Resistant to
    Brassica 1 Aphids
    Flat bean Pusa sem 2
    Okera Bhindi 3 Shoot and fruit borer
  • 4)

    Besides conventional breeding technique for disease resistant  varieties,  now  a  day  a  new breeding technique is practiced. How it is advantageous over the conventional technique or what is the drawback of this technique?

  • 5)

    Why is it easier to culture meristems compared to permanent tissues?

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    It is easier to culture plants cells in vitro as compared to animal cells. Why?

  • 2)

    How are two following varieties of sugarcane different from reach other?
    (i) Saccharum Barberi
    (ii) Saccharum officinarum

  • 3)

    It is estimated that more than 70% of the world livestock population is in India and China. Yet they contribute only 25% of the world’s farm produce .What does it indicates. How can we improve it?

  • 4)

    As the population is continuously increasing and land for agriculture is decreasing. So how we can overcome food scarcity problem. Suggest two measures.

  • 5)

    Genetic variability is the root of any breeding program. How can these naturally occurring genetic variations be used for benefit to mankind and the biosphere in general.

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production HOT Questions 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    A person who is allergic to pulses is advised to take a capsule of spirulina daily.Give the reason for the advice.

  • 2)

    It is easier to culture plants cells in vitro as compared to animal cells. Why?

  • 3)

    How are two following varieties of sugarcane different from reach other?
    (i) Saccharum Barberi
    (ii) Saccharum officinarum

  • 4)

    As the population is continuously increasing and land for agriculture is decreasing. So how we can overcome food scarcity problem. Suggest two measures.

  • 5)

    Genetic variability is the root of any breeding program. How can these naturally occurring genetic variations be used for benefit to mankind and the biosphere in general.

CBSE 12th Standard Biology Subject Human Health and Disease HOT Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    (a) Why do the symptoms of malaria not appear immediately after the entry of sporozoites into the human body,when bitten by female Anopheles? Explain.
    (b) Give the scientific name of the malarial parasite that causes malignant malaria in humans .

  • 2)

    Think what two measures should be taken for prevention and control of alcohol and drug abuse among adolescents

  • 3)

    Given below are pairs of disease and causative organism. Which out of these is not these is not a matching pair and why?
    Filariasis  : Wuchereria
    Ringworm : Ascaris
    AIDS        :  Human Immunodeficiency virus
    Malaria     : Plasmodium  

  • 4)

    A thalasemic child needed repeated blood transfusions, got infected by HIV.
    (i) use a rough diagramatic sketch and arrows to show how the virus increased in number.
    (ii) Why did the increased number of HIV viruses deteriorate the child's immunity?
    (iii) Which diagnostic test showed that the infective virus was HIV?

  • 5)

    Give Reasons for the following statements:
    (a) Neutrophils and macrophages are called soldiers and scavengers of the animal body.
    (b) After consuming alcohol, one should avoid driving.
    (c) Persistent use of corticosteroids is harmful.

CBSE 12th Standard Biology Subject Human Health and Disease HOT Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    (a) Why do the symptoms of malaria not appear immediately after the entry of sporozoites into the human body,when bitten by female Anopheles? Explain.
    (b) Give the scientific name of the malarial parasite that causes malignant malaria in humans .

  • 2)

    Think what two measures should be taken for prevention and control of alcohol and drug abuse among adolescents

  • 3)

    Given below are pairs of disease and causative organism. Which out of these is not these is not a matching pair and why?
    Filariasis  : Wuchereria
    Ringworm : Ascaris
    AIDS        :  Human Immunodeficiency virus
    Malaria     : Plasmodium  

  • 4)

    A thalasemic child needed repeated blood transfusions, got infected by HIV.
    (i) use a rough diagramatic sketch and arrows to show how the virus increased in number.
    (ii) Why did the increased number of HIV viruses deteriorate the child's immunity?
    (iii) Which diagnostic test showed that the infective virus was HIV?

  • 5)

    List the causative organism and carrier of the following diseases.
    (i) Dengue fever
    (ii) Chikungunya

CBSE 12th Standard Biology Subject Human Health and Disease HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why are the tumour cells dangerous?

  • 2)

    (a) Explain the property that prevents normal cells from becoming cancerous.
    (b) All normal cells have inherent characteristic of becoming cancerous.Explain.

  • 3)

    Many microbial pathogens enter the gut of humans along with food.What are the preventive barriers to protect the body from such pathogens?What type of immunity do you observe in this case?

  • 4)

    Name the types of barrier of innate immune system, which involves
    (i) HCI of stomach    
    (ii) macrophages.

  • 5)

    Why is tobacco smoking associated with rise in blood pressure and emphysema (Oxygen deficiency in the body)? Explain.

CBSE 12th Standard Biology Subject Human Health and Disease HOT Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Name and explain the type of immunity that is provided by injecting microbes deliberately during immunisation into the human body.

  • 2)

    Why does a doctor administer tetanus antitoxoid and not a tetanus vaccine to a child injured in a roadside accident with a bleeding wound?Explain.

  • 3)

    Why are the tumour cells dangerous?

  • 4)

    (a) Explain the property that prevents normal cells from becoming cancerous.
    (b) All normal cells have inherent characteristic of becoming cancerous.Explain.

  • 5)

    Name the types of barrier of innate immune system, which involves
    (i) HCI of stomach    
    (ii) macrophages.

CBSE 12th Standard Biology Subject Human Health and Disease HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why does an AIDS patient suffer from many other infections?

  • 2)

    How does tobacco smoking lead to oxygen deficiency in human body?

  • 3)

    ‘Rahul was suffering from common cold and was severely coughing and sneezing in the class. His science teacher asked him to use his handkerchief and also explained the reason to do so.’ What could have been the reason behind the decision taken by the teacher?

  • 4)

    The doctor on examining a particular patient found that his lips and fingernails had turned gray and the patient was also feeling un-healthy. What diagnosis did the doctor made ? What other symptoms could he have observed in the patient?

  • 5)

    A doctor was explaining to his students about a particular disease vector that booms particularly during the rainy season (warm and humid). He also explained that one of the type of this disease can show shivering effect and may be fatal. Name the type and its causative agent. Also explain the reason for the other symptoms of the disease?

CBSE 12th Standard Biology Subject Human Health and Disease HOT Questions 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why is sharing of injection needles between two individuals not recommended?

  • 2)

    What is it that prevents a child to suffer from a disease he/she is vaccinated against?Give one reason.

  • 3)

    Which category of adaptive immunity is provided by vaccination? Why?

  • 4)

    Why does an AIDS patient suffer from many other infections?

  • 5)

    How does tobacco smoking lead to oxygen deficiency in human body?

CBSE 12th Standard Biology Subject Evolution HOT Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Anthropogenic action can hasten evolution. Explain with the help of a suitable example.

  • 2)

    The study of
    (i) fossils of dinosaurs
    (ii) forelimbs of Cheeta, bat and human
    (ii) thorns of Bougainvillea and tendril of Cucurbita shows that evolution of life forms has indeed taken place on earth. Explain.

  • 3)

    Study the given figures (a) and (b) and answer the questions given below:

    (i) Under the influence of which type of natural selection would graph (a) becomes like graph (b)?
    (ii) What could be the likely reasons of new variations arising in the population?
    (iii) Who suggested natural selection as a mechanism of evolution?

  • 4)

    How did Louis Paster successfully demolish the popular theory of spontaneous generation?

  • 5)

    In 1950s, there were hardly any mosquitoes in Delhi. The use of the pesticide DDT on standing water killed their larvae. It is believed that now there are mosquitoes because they evolved DDT resistance through the interaction of mutation and natural selection. Pointwise state in a sequence how that could have happened?

CBSE 12th Standard Biology Subject Evolution HOT Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Anthropogenic action can hasten evolution. Explain with the help of a suitable example.

  • 2)

    The study of
    (i) fossils of dinosaurs
    (ii) forelimbs of Cheeta, bat and human
    (ii) thorns of Bougainvillea and tendril of Cucurbita shows that evolution of life forms has indeed taken place on earth. Explain.

  • 3)

    In 1950s, there were hardly any mosquitoes in Delhi. The use of the pesticide DDT on standing water killed their larvae. It is believed that now there are mosquitoes because they evolved DDT resistance through the interaction of mutation and natural selection. Pointwise state in a sequence how that could have happened?

  • 4)

    State in what ways Stanely Miller simulated the conditions of:
    (i) primitive atmosphere on earth.
    (ii) energy source at the time of origin of life, and
    (iii) formation of organic molecules of life to prove the theory of chemical evolution?

  • 5)

    Can the host-parasite relationship provide evidence for evolution? Explain.

CBSE 12th Standard Biology Subject Evolution HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why are the wings of butterfly and birds said to be analogous organs? Name the type of evolution, the analogous organs are a result of.

  • 2)

    Evolution is not a direct process, but a stochastive process, based on chance event(s) in nature. Justify.

  • 3)

    Discuss, is evolution a process or the end result of a process.

  • 4)

    Write down 4 important resemblances between apes and humans.

  • 5)

    (i) Select the homologous structures from the combinations given below :
    (a) Forelimbs of whales and bats
    (b) Tuber of potato and sweet potato
    (c) Eyes of octopus and mammals
    (d) Thorns of Bougainvillea and tendrils of Cucurbitta
    (ii) State the kind of evolution they represent.

CBSE 12th Standard Biology Subject Evolution HOT Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why are the wings of butterfly and birds said to be analogous organs? Name the type of evolution, the analogous organs are a result of.

  • 2)

    Evolution is not a direct process, but a stochastive process, based on chance event(s) in nature. Justify.

  • 3)

    Discuss, is evolution a process or the end result of a process.

  • 4)

    Write down 4 important resemblances between apes and humans.

  • 5)

    (i) Select the homologous structures from the combinations given below :
    (a) Forelimbs of whales and bats
    (b) Tuber of potato and sweet potato
    (c) Eyes of octopus and mammals
    (d) Thorns of Bougainvillea and tendrils of Cucurbitta
    (ii) State the kind of evolution they represent.

CBSE 12th Standard Biology Subject Evolution HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Comment on the similarity between the wing of a cockroach and the wing of a bird. What do you infer from the above with reference to evolution?

  • 2)

    Rearrange the following statements to explain the formation of atmosphere on earth 
    i) The lighter hydrogen gas escaped from the surface while oxygen combined with methane, ammonia etc to form water and carbondioxide etc.
    ii) Earth cooled and water vapour fell as rain
    iii) Water vapour, methane, ammonia and carbondaioxide were released from molten mass.
    iv) UV rays from the sun broke up water into hydrogen and oxygen.

  • 3)

    Name the theory of origin based on the following statement;
    i) The supernatural being created the earth, light, plants, animals
    ii) Unit of life called spores transferred to different planets including earth.
    iii) Life arose from decaying matter like straw.
    iv) First form of life could have come from pre-existing non-living organic molecules.
    v) The first form of life arose slowly from non-living molecules involving evolutionary forces.

  • 4)

    Stanley Miller & Urey experimentally proved the chemical evolution of life by creating condition similar to the primitive atmosphere, in the laboratory. Name the gases filled by them in the flask .In what form was the energy supplied for the chemical reaction to occur? For how long the experiments run continuously?

  • 5)

    Charles Darwin during a Sea voyage round the world in a sail ship (H.M.S Beagle), concluded that there has been gradual evolution of life forms . What is his theory practically known as? Write the main points of his theory . Name a scientist who arrived to similar conclusion like that of Charles Darwin?

CBSE 12th Standard Biology Subject Evolution HOT Questions 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Write the similarity between the wing of a butterfly and the wing of a bat. What do you infer the above with reference to evolution?

  • 2)

    Comment on the similarity between the wing of a cockroach and the wing of a bird. What do you infer from the above with reference to evolution?

  • 3)

    Charles Darwin during a Sea voyage round the world in a sail ship (H.M.S Beagle), concluded that there has been gradual evolution of life forms . What is his theory practically known as? Write the main points of his theory . Name a scientist who arrived to similar conclusion like that of Charles Darwin?

  • 4)

    What is indicated by a cross section of earth’s crust? Name the evolutionary evidence in which different aged rock sediments containing fossil of life form are examined?

  • 5)

    Whales, bats, cheetah & humans shares similarities in the pattern of bones of forelimbs what do we call these structures. How these structures are pointing towards divergent evolution? Give an example from plants which represent the same pattern?

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance HOT Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)


    Why do you see two different types of replicating strands in the given DNA replication fork? Name these strands.

  • 2)

    (a) Name the type of synthesis 
    (b) Occurrence in the types of synthesis and as shown below: 

  • 3)

    A primer comprising of 5 bases is required to allow copying of the following single standard DNA sequence 5'-ATGCCTAGGTC
    Name the appropriate primer that should start DNA replication

  • 4)

    Calculate the total number of thymine-based present in the double strand DNA if it transcribes a mRNA which reads as follows:
    5'-AUGCAUGCAUGCAUGCAGG-3'

  • 5)

    How many histones make the core part of a nucleosome.What is the basis of binding DNA molecule to the histones?

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance HOT Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    (i)Why does DNA replication occur in small replication forks and not in its entire length?
    (ii)Why is DNA replication countinuous and discountinuous in a replication fork?
    (iii)Explain the importance of 'origin of replication' in a replication fork.

  • 2)

    (a) Name the type of synthesis 
    (b) Occurrence in the types of synthesis and as shown below: 

  • 3)

    How many histones make the core part of a nucleosome.What is the basis of binding DNA molecule to the histones?

  • 4)

    Write the principle involved in the separation of DNA fragments by gel electrophoresis

  • 5)

    Here some correct and some wrong statements.Correct only those statements which are wrong:
    (a) The genetic code is universal 
    (b)The genetic code is ambiguous
    (c)The genetic code is regenerated.
    (d)Transfer RNA(tRNA)carry amino acids to mRNA codons and used again and again in transcription.
    (e)UAA, UAG and UGC are terminator codon
    (f)Lac operon consists of regulatory genes, operator gene,structural and promoter gene

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why is it that transcription and translation can be coupled in prokaryotic cells but not in eukaryotic cells?

  • 2)

    Regulation of lac operon can be visualised as regulation of enzyme synthesis by its substrate. Explain the statement.

  • 3)

    Study the given portion of double stranded polynucleotide chain carefully. Identify a,b,c and 5' end of the chain.

  • 4)

    There in only one possible sequence of amino acids when deduced from a given set of nucleotides.But multiple nucleotide sequences can be deduced from a single amino acid sequence .Explain this phenomenon.

  • 5)

    A single base mutation in a gene may not 'always' result in loss or gain of function.Do you think the statement is correct?Define your answer.

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance HOT Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Recall the experiment of Frederick Griffith.If RNA instead of DNA was the genetic material would the heat-killed S-strain of the bacteria have transformed the R-strain into S-strain? Explain your answer

  • 2)

    Why is it that transcription and translation can be coupled in prokaryotic cells but not in eukaryotic cells?

  • 3)

    Regulation of lac operon can be visualised as regulation of enzyme synthesis by its substrate. Explain the statement.

  • 4)

    Study the given portion of double stranded polynucleotide chain carefully. Identify a,b,c and 5' end of the chain.

  • 5)

    There in only one possible sequence of amino acids when deduced from a given set of nucleotides.But multiple nucleotide sequences can be deduced from a single amino acid sequence .Explain this phenomenon.

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why do certain genes tend to be inherited together in a cell at the time of cell division?

  • 2)

    When a tall pea plant was self-pollinated, one-fourth of the progency were dwarf.  Give the genotype of the parent and the dwarf progenies.

  • 3)

    Do you think Mendel's law of inheritance would have been different if the characters he chose were located on the same chromosome? Why?

  • 4)

    What is the proof for or what indicates that the characters Mendel studied did not show blending?

  • 5)

    Which of the following is a recessive or dominant trait in garden pea?
    a) Tall stem b) Wrinkled seeds c) Green color seed coat d) Constricted pod.

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance HOT Questions 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    In a test cross progeny of pea plats, all were bearing violet flowers. Give the genotypes of the parent pea plants.

  • 2)

    Why do certain genes tend to be inherited together in a cell at the time of cell division?

  • 3)

    When a tall pea plant was self-pollinated, one-fourth of the progency were dwarf.  Give the genotype of the parent and the dwarf progenies.

  • 4)

    What is the proof for or what indicates that the characters Mendel studied did not show blending?

  • 5)

    Name and state the law of Mendel, which explains the expression of only one of the parental characters in the F1 generation of a monohybrid cross.

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation HOT Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Identify the phenomenon in the following example-
    "Sickle cell anaemia is an autosomal recessive trait.It is caused by the substitution of anino acid glutamic acid by valine at the sixth position of the beta globin chain of haemoglobin.This substitution of amino acid occurs due to phenomenon in which the sixth codon of beta globin gene is transformed from GAG to GUG".

  • 2)

    Morgan(1910) made the following crosses in Drosophilla.Write the results of these crosses in F1 generation. 
    (a) The white eyed male was crossed with red eyed female.
    (b) The females of F1 generation were crossed with red eyed males.
    (c) White eyed females were crossed with red eyed males.

  • 3)

    A man having blood group A is married with an woman having blood group B.work out the genotype of man and woman if their one of the children is born with blood group O.what is the possible genotype of other offsprings.

  • 4)

    Whiich phenomenon strongly favours the linear arrangement of genes on the chromosomes?Define the phenomenon and give the situation where this phenomenon cannot occur.

  • 5)

    Determine the genotype of offsprings in a cross between normal male and female cockroaches.

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation HOT Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Identify the phenomenon in the following example-
    "Sickle cell anaemia is an autosomal recessive trait.It is caused by the substitution of anino acid glutamic acid by valine at the sixth position of the beta globin chain of haemoglobin.This substitution of amino acid occurs due to phenomenon in which the sixth codon of beta globin gene is transformed from GAG to GUG".

  • 2)

    A man having blood group A is married with an woman having blood group B.work out the genotype of man and woman if their one of the children is born with blood group O.what is the possible genotype of other offsprings.

  • 3)

    Flowers of garden pea are biseual and self pollinated.therefore,it is difficult to perform hybrindization experiment by crossing a particular pistil with the specific pollen grains.Hoew mendel made it possible in his monohybrid, dihybrid and trihybrid crosses?

  • 4)

    Determine the genotype of offsprings in a cross between normal male and female cockroaches.

  • 5)

    How many linkage groups are present in the organism whose genomic chromosome number is n=8?

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    In a cross between two tall pea plants, some of the offspring produced were dwarf.  Show with the help of a Punnet square, how this is possible.

  • 2)

    Inheritance is particulate in nature. Justify.

  • 3)

    Not all characters show true dominance what are the two other possible types of dominance? Give an example of each type.

  • 4)

    Why does the son of a carrier mother and a normal father suffer from haemophilia, whereas the son of a haemophilic father and a normal mother would not?

  • 5)

    The pedigree chart given below shows a particular trait which is absent in parents but present in the next generation irrespective of sexes.
    Draw your conclusion on the basis of the pedigree.

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation HOT Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    In a cross between two tall pea plants, some of the offspring produced were dwarf.  Show with the help of a Punnet square, how this is possible.

  • 2)

    Inheritance is particulate in nature. Justify.

  • 3)

    Not all characters show true dominance what are the two other possible types of dominance? Give an example of each type.

  • 4)

    Why does the son of a carrier mother and a normal father suffer from haemophilia, whereas the son of a haemophilic father and a normal mother would not?

  • 5)

    The pedigree chart given below shows a particular trait which is absent in parents but present in the next generation irrespective of sexes.
    Draw your conclusion on the basis of the pedigree.

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    In a test cross progeny of pea plats, all were bearing violet flowers. Give the genotypes of the parent pea plants.

  • 2)

    Why do certain genes tend to be inherited together in a cell at the time of cell division?

  • 3)

    When a tall pea plant was self-pollinated, one-fourth of the progency were dwarf.  Give the genotype of the parent and the dwarf progenies.

  • 4)

    What is the proof for or what indicates that the characters Mendel studied did not show blending?

  • 5)

    Name and state the law of Mendel, which explains the expression of only one of the parental characters in the F1 generation of a monohybrid cross.

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation HOT Questions 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    In a test cross progeny of pea plats, all were bearing violet flowers. Give the genotypes of the parent pea plants.

  • 2)

    Why do certain genes tend to be inherited together in a cell at the time of cell division?

  • 3)

    When a tall pea plant was self-pollinated, one-fourth of the progency were dwarf.  Give the genotype of the parent and the dwarf progenies.

  • 4)

    Do you think Mendel's law of inheritance would have been different if the characters he chose were located on the same chromosome? Why?

  • 5)

    What is the proof for or what indicates that the characters Mendel studied did not show blending?

CBSE 12th Standard Biology Subject Reproductive Health HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Although AIDS is a fluid transmitted disease, it is considered as an STD. Give a reason for it.

  • 2)

    Explain how surrogacy is helpful in case of infertile women.

  • 3)

    Shyam Lal and his wife have been advised by the gynecologist to go for artificial insemination. What may have been the reason for the doctor to give such an advice? Explain.

  • 4)

    All reproductive tract infections are STDs, but not all STDs are reproductive infections. Justify with an example.

  • 5)

    The procedure of GIFT involves the transfer of female gamete to the fallopian tube. Can the gamete be transferred to the uterus to achieve the same result? Explain.

CBSE 12th Standard Biology Subject Reproductive Health HOT Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    What do oral pills contain and how do they act as effective contraceptives?

  • 2)

    Although AIDS is a fluid transmitted disease, it is considered as an STD. Give a reason for it.

  • 3)

    Explain how surrogacy is helpful in case of infertile women.

  • 4)

    Shyam Lal and his wife have been advised by the gynecologist to go for artificial insemination. What may have been the reason for the doctor to give such an advice? Explain.

  • 5)

    All reproductive tract infections are STDs, but not all STDs are reproductive infections. Justify with an example.

CBSE 12th Standard Biology Subject Reproductive Health HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    How do hormonal pills work as contraceptives?

  • 2)

    "Creating awareness among people about various reproductions related aspect and providing facilities and support for building up a reproductively healthy society are the major tasks of a good government. For this various programmes are undertaken". Name the programs?

  • 3)

    A diagnostic technique in which a sample of amniotic fluid is taken from the womb of a pregnant commonly known during the early stages of foetal development. By what name is this method commonly known as? What can be detected by it?

  • 4)

    Advancement in technology avoids hunger death, decline in infant mortality rate, and increase in number of people in the reproductive age, etc. These are the contributing factors for what type explosion?

  • 5)

    In vitro fertilization refers to the fusion gametes outside the reproductive canal almost in similar condition as that exist in the body. Mention the popular name?

CBSE 12th Standard Biology Subject Reproductive Health HOT Questions 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    State one reason why breast-feeding the baby acts as a natural contraceptive for the mother.

  • 2)

    How do hormonal pills work as contraceptives?

  • 3)

    "Creating awareness among people about various reproductions related aspect and providing facilities and support for building up a reproductively healthy society are the major tasks of a good government. For this various programmes are undertaken". Name the programs?

  • 4)

    It is a method involving the transfer of a ovum collected from a donor female into reproductive canal of another female, who cannot produce ova but can provide suitable condition for fertilization and further growth from embryo stage up to parturition. Name  the method?

  • 5)

    In vitro fertilization refers to the fusion gametes outside the reproductive canal almost in similar condition as that exist in the body. Mention the popular name?

CBSE 12th Standard Biology Subject Human Reproduction HOT Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    How many spermatozoa are produced from a secondary spermatocyte and how many ova are produced from a primary oocyte?

  • 2)

    Mention the essential of LH surge during menstrual cycle.

  • 3)

    What name is given to the placenta in which trophoblastic villi and walls of uterine vessels degenerate so that foetal capillaries are bathed in uterine blood?

  • 4)

    Women experience two major events in their lifetime one at menarche and the second at menopause, mention the characteristics of both the events.

  • 5)

    Given reasons for the following statements:
    (a) Parturition is also termed labour.
    (b) Early secretions from mammary glands of mother are very useful to newly born baby.
    (c) Testes in males are lodged in the scrotum so as lie outside the abdominal cavity.

CBSE 12th Standard Biology Subject Human Reproduction HOT Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    How many spermatozoa are produced from a secondary spermatocyte and how many ova are produced from a primary oocyte?

  • 2)

    Mention the essential of LH surge during menstrual cycle.

  • 3)

    What name is given to the placenta in which trophoblastic villi and walls of uterine vessels degenerate so that foetal capillaries are bathed in uterine blood?

  • 4)

    Women experience two major events in their lifetime one at menarche and the second at menopause, mention the characteristics of both the events.

  • 5)

    Given reasons for the following statements:
    (a) Parturition is also termed labour.
    (b) Early secretions from mammary glands of mother are very useful to newly born baby.
    (c) Testes in males are lodged in the scrotum so as lie outside the abdominal cavity.

CBSE 12th Standard Biology Subject Human Reproduction HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    (a) How many spermatozoa are formed from one secondary spermatocyte?
    (b) Where does the first cleavage division of zygote take place?

  • 2)

    Why is it considered that the presence or absence of hymen is not an indication of virginity?

  • 3)

    List the different parts of human oviduct through which the ovum travels till it meets the sperm for fertilisation.

  • 4)

    What is the number of chromosomes in the following cells of a human male?
    (i) Spermatogonial cells
    (ii) Spermatids
    (iii) Primary spermatocytes
    (iv) Sertoli cells

  • 5)

    What lead to menstruation in the absence of fertilisation?

CBSE 12th Standard Biology Subject Human Reproduction HOT Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    (a) How many spermatozoa are formed from one secondary spermatocyte?
    (b) Where does the first cleavage division of zygote take place?

  • 2)

    Why is it considered that the presence or absence of hymen is not an indication of virginity?

  • 3)

    Why not all copulations lead to fertilisation and pregnancy?

  • 4)

    A mother gets infected with a virus which causes German measles during pregnancy. Is it possible that the foetus will also get infected? How ? What are its ill-effect on the foetus?

  • 5)

    How is the action of LH different in male and female?

CBSE 12th Standard Biology Subject Human Reproduction HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    During reproduction,the chromosome number (2n) reduces to half (n) in the gametes and again the original number (2n) is restored in the offspring.What are the process through which these events take place?

  • 2)

    Why is the middle piece of human sperm considered as 'powerhouse of the sperm'?

  • 3)

    Somatic chromosome number is 40. What shall be the chromosome number in the cells of seminiferous tubules?

  • 4)

    Name the stages when oogenesis and spermatogenesis initiate in human female and male, respectively?

  • 5)

    Luteal phase of the menstrual cycle is also called the secretory phase. Give reason.

CBSE 12th Standard Biology Subject Human Reproduction HOT Questions 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    During reproduction,the chromosome number (2n) reduces to half (n) in the gametes and again the original number (2n) is restored in the offspring.What are the process through which these events take place?

  • 2)

    What stimulates pituitary to release the hormone responsible for parturition? Give the name of hormone.

  • 3)

    Cervix contains the largest and the strongest sphincter in its wall. Give reason.

  • 4)

    Spermatogenesis is a continuous process but its release is not. How reproductive system does manage this situation?

  • 5)

    Based on the above question, explain that under what physiological conditions are the sperms managed and what changes are brought before their release?

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants HOT Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Embryo sacs of some apomictic species appear normal, but contain diploid cells. Suggest a suitable explanation for the condition.

  • 2)

    In case of polyembryony, if one embryo develops from the synergid and another from the nucellus, which one is haploid and which is diploid? Describe polyembryony and also mention how can it be commercially exploited.

  • 3)

    Ram saw a farmer spraying some chemicals on flowers. On asking farmer, he came to know that this act will lead to the formation of fruits without fertilisation. Ram thought that fruits developed in this way are not good to eat as chemicals are sprayed on it.
    Next day, he asked his biology teacher about it, who explained him everything.
    (i) What chemicals were sprayed by the farmer?
    (ii) Give difference between such a spray and usual pesticide spray?
    (iii) What is parthenocarpy? Give its types.
    (iv) What values are shown by Ram?

  • 4)

    During a biology lecture in class the teacher called apple seeds as seeds but maize seeds as grains. On hearing this Amit got confused and asks her teacher the reason behind this. The teacher appreciated Amit and cleared all his doubts.
    (i) What is the difference between seed and grain?
    (ii) How are maize grains formed?
    (iii) Explain along with a labelled diagram of the vertical section of a maize grain.
    (iv) What values are shown by Amit.

  • 5)

    Give reasons why:
    (i) most zygotes in angiosperms divide only after certain amount of endosperm is formed.
    (ii) groundnut seeds are exalbuminous and castor seeds 'are albuminous.
    (iii) micropyle remains as a small pore in the seed coat of a seed.
    (iv) integuments of an ovule harden and the water content is highly reduced, as the seed matures.
    (v) apple and cashew are not called true fruits.

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants HOT Questions 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    (a) Draw a labelled diagram of L.S. of an embryo of grass (any six labels).
    (b) Give reason for each of the following:
    (i) Anthers of angiosperm flowers are described as dithecous.
    (ii) Hybrid seeds have to be produced year after year.

  • 2)

    Double fertilisation is immediately followed by development of endosperm. Explain the link between the two processes.

  • 3)

    Embryo sacs of some apomictic species appear normal, but contain diploid cells. Suggest a suitable explanation for the condition.

  • 4)

    In case of polyembryony, if one embryo develops from the synergid and another from the nucellus, which one is haploid and which is diploid? Describe polyembryony and also mention how can it be commercially exploited.

  • 5)

    Ram saw a farmer spraying some chemicals on flowers. On asking farmer, he came to know that this act will lead to the formation of fruits without fertilisation. Ram thought that fruits developed in this way are not good to eat as chemicals are sprayed on it.
    Next day, he asked his biology teacher about it, who explained him everything.
    (i) What chemicals were sprayed by the farmer?
    (ii) Give difference between such a spray and usual pesticide spray?
    (iii) What is parthenocarpy? Give its types.
    (iv) What values are shown by Ram?

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants HOT Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    On the basis of relative position of funicle, chalaza and micropyle, the ovules can be classified into following six types. Identify the type of ovule from the diagrams given below and name them.

  • 2)

    (i) Can a plant flowering in Mumbai be pollinated by pollen grains of the same species growing in New Delhi? Provide explanation to your answer.
    (ii) Draw the diagram of a pistil where pollination has successfully occurred. Label the parts involved in reaching the male gametes to its desired destination.

  • 3)

    Given below are the events that are observed in an artificial hybridisation programme. Selection of parents \(\rightarrow\) Emasculation \(\rightarrow\)Bagging \(\rightarrow\) Collection of pollen from other male plant \(\rightarrow\) Dusting of pollen on stigma \(\rightarrow\) Rebagging. While, planning for crop improvement involving dioecious plants, which of the above mentioned steps would not be relevant?

  • 4)

    Vivipary automatically limits the number of offsprings in a litter. How?

  • 5)

    If the meiocyte of a maize plant contains 20 chromosomes, write the number of chromosomes in the endosperm and embryo of the maize grain and give reasons in support of your answer.

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants HOT Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    On the basis of relative position of funicle, chalaza and micropyle, the ovules can be classified into following six types. Identify the type of ovule from the diagrams given below and name them.

  • 2)

    (i) Can a plant flowering in Mumbai be pollinated by pollen grains of the same species growing in New Delhi? Provide explanation to your answer.
    (ii) Draw the diagram of a pistil where pollination has successfully occurred. Label the parts involved in reaching the male gametes to its desired destination.

  • 3)

    Given below are the events that are observed in an artificial hybridisation programme. Selection of parents \(\rightarrow\) Emasculation \(\rightarrow\)Bagging \(\rightarrow\) Collection of pollen from other male plant \(\rightarrow\) Dusting of pollen on stigma \(\rightarrow\) Rebagging. While, planning for crop improvement involving dioecious plants, which of the above mentioned steps would not be relevant?

  • 4)

    Vivipary automatically limits the number of offsprings in a litter. How?

  • 5)

    If the meiocyte of a maize plant contains 20 chromosomes, write the number of chromosomes in the endosperm and embryo of the maize grain and give reasons in support of your answer.

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    In case of polyembryony, if an embryo develops from the synergid and another from the nucellus, which is haploid and which is diploid? 

  • 2)

    Geitonogamous flowering plants are genetically autogamous, but functionally cross-pollinated. Justify.

  • 3)

    Explain how geitonogamy is functionally similar to cross-pollination and genetically similar to autogamy.

  • 4)

    If you squeeze a seed of orange, you might observe many embryos of different sizes. How is it possible? Explain.

  • 5)

    Why should a breeder need to emasculate a bisexual flower? Mention a condition in a flower, where emasculation is not necessary?

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants HOT Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Explain how geitonogamy is functionally similar to cross-pollination and genetically similar to autogamy.

  • 2)

    If you squeeze a seed of orange, you might observe many embryos of different sizes. How is it possible? Explain.

  • 3)

    Why should a breeder need to emasculate a bisexual flower? Mention a condition in a flower, where emasculation is not necessary?

  • 4)

    Are pollination and fertilisation necessary in apomixis? Give reason.

  • 5)

    Why do species with abiotic mode of pollination produce larger number of pollen-grains, when compared to those with biotic pollination?

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why is banana considered a good example of parthenocarpy?

  • 2)

    A bilobed dithecous anther has 100 microspore mother cells per microsporangium. How many male gametophytes can this anther produce?

  • 3)

    Pea flowers produce assured seed sets. Given a reason.

  • 4)

    Banana is a fruit as well as a parthenocarpic fruit. Give reason.

  • 5)

    It is the tissue in the ovary on which the ovules develop and are attached to the ovary wall.  Name this tissue located inside the ovarian cavity?

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants HOT Questions 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    An anther with malfunctioning tapetum often fails to produce viable male gametophyte. Give any one reason. 

  • 2)

    Why is banana considered a good example of parthenocarpy?

  • 3)

    Cleistogamy can favour only autogamy. Justify.

  • 4)

    Give the name of a phenomenon in which separate male and female flowers are borne on the same individual at different positions to prevent autogamy.

  • 5)

    How is it possible in Oxalis and Viola to produce assured seed sets even in the absence of its pollinators?

CBSE 12th Standard Biology Subject Reproduction in Organisms HOT Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Although potato tuber is an underground plant part, it is considered as a stem. Give two reasons.

  • 2)

    In an experiment, Mr. Jhon dissected a large potato tuber into serval small pieces and then placed each piece in a separate pot for germination. After few days, he observed that a few pieces germinated and developed new plants. The others did not germinate at all. Give the possible reasons.

  • 3)

    A gardener grafted a scion of "Dashahari" mango twig to the stock of Zea mays. He took all precautions during the grafting process but failed to get positive results as the grafting was not successful. Give the possible reason.

  • 4)

    Select out any four animals to demonstrate examples of bisexual organism:
    Frog, Earthworm, Cockroach, Spider, Sponge, tapeworm, leech, honey, bee, Rat, Rabbit, House fly.

  • 5)

    Ramesh tried to propagate sugarcane vegetatively by sowing a segment of stem having internodal region only. Suresh tried the same by sowing a segment having an internode. Who chose the correct segment and why?

CBSE 12th Standard Biology Subject Reproduction in Organisms HOT Questions 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Although potato tuber is an underground plant part, it is considered as a stem. Give two reasons.

  • 2)

    In an experiment, Mr. Jhon dissected a large potato tuber into serval small pieces and then placed each piece in a separate pot for germination. After few days, he observed that a few pieces germinated and developed new plants. The others did not germinate at all. Give the possible reasons.

  • 3)

    A gardener grafted a scion of "Dashahari" mango twig to the stock of Zea mays. He took all precautions during the grafting process but failed to get positive results as the grafting was not successful. Give the possible reason.

  • 4)

    Select out any four animals to demonstrate examples of bisexual organism:
    Frog, Earthworm, Cockroach, Spider, Sponge, tapeworm, leech, honey, bee, Rat, Rabbit, House fly.

  • 5)

    Ramesh tried to propagate sugarcane vegetatively by sowing a segment of stem having internodal region only. Suresh tried the same by sowing a segment having an internode. Who chose the correct segment and why?

CBSE 12th Standard Biology Subject Reproduction in Organisms HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    The cell division involved in gamete formation is not of the same type in different organisms.  Justify.

  • 2)

    Reptiles and frogs are oviparous animals; yet they differ in certain aspects of reproduction.  Bring out the differences and mention which of the two animals has more advantage in survival.

  • 3)

    Why is it that there is no natural death in single-celled organisms like Amoeba and bacteria?

  • 4)

    In oogamy, female gamete is large and non-motile but the male gamete is reverse in its properties. Why such type of adjustment is there in higher organisms?

  • 5)

    How do gemmules and gemma cup differ from each other?

CBSE 12th Standard Biology Subject Reproduction in Organisms HOT Questions 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Unicellular organisms are immortal, whereas multicellular organisms are not.  Justify.

  • 2)

    Reptiles and frogs are oviparous animals; yet they differ in certain aspects of reproduction.  Bring out the differences and mention which of the two animals has more advantage in survival.

  • 3)

    Why is it that there is no natural death in single-celled organisms like Amoeba and bacteria?

  • 4)

    In oogamy, female gamete is large and non-motile but the male gamete is reverse in its properties. Why such type of adjustment is there in higher organisms?

  • 5)

    How do gemmules and gemma cup differ from each other?

CBSE 12th Standard Biology Subject Reproduction in Organisms HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    How are Cucurbita plants different from papaya plants with reference to the flowers they bear?

  • 2)

    All papaya plants bear flowers, but fruits are seen only in some.  Explain.

  • 3)

    Offspring derived by asexual reproduction are called clones.  Justify giving two reasons.

  • 4)

    In yeast and Amoeba, the parent cell divides to gives rise to two new individual cells.  How does the cell division differ in these two organisms?

  • 5)

    Why do internodal sagments of sugar cane fail to propagate vegetatively even when they are in contact with damp soil?

CBSE 12th Standard Biology Subject Reproduction in Organisms HOT Questions 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Cucurbits and papaya plants bear staminate and pistillate flowers.  Mention the categories they are put under separately on the basic of the type of flowers they bear.

  • 2)

    How are Cucurbita plants different from papaya plants with reference to the flowers they bear?

  • 3)

    All papaya plants bear flowers, but fruits are seen only in some.  Explain.

  • 4)

    Meiosis generally occurs during gametogenesis in sexually reproducing organisms.Why?

  • 5)

    Although potato tuber is an underground part, it is considered as steam, why?

CBSE 12th Standard Biology Subject HOT Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    (a) Draw a labelled diagram of L.S. of an embryo of grass (any six labels).
    (b) Give reason for each of the following:
    (i) Anthers of angiosperm flowers are described as dithecous.
    (ii) Hybrid seeds have to be produced year after year.

  • 2)

    (a) A garden pea plant bearing terminal, violet flowers, when crossed with another pea plant bearing axial, violet flowers produced axial, violet flowers in the ratio of 3 : 1.
    Work out the cross showing the genotypes of the parent pea plants and their progeny.
    (b) Name and state the law that can be derived from this cross and not from a mohohybrid cross.

  • 3)

    Why is aerobic degradation more important than anaerobic degradation for the treatment of large volumes of waste water in organic matter. Discuss.

  • 4)

    'Sperm donation can help infertile couples' Justify. In Which type of cases, such sperm donation is helpful?

  • 5)

    Answer the following questions related to Down's syndrome.
    (i) When was Down's syndrome first described?
    (ii) What is its frequency in human and does it also occur in other animals?
    (iii) How does Down's syndrome arise?
    (iv) Related it with chromosome dysfunctions.

CBSE 12th Standard Biology Subject HOT Questions 5 Marks Questions 2021 Part - II - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    (a) Draw a labelled diagram of L.S. of an embryo of grass (any six labels).
    (b) Give reason for each of the following:
    (i) Anthers of angiosperm flowers are described as dithecous.
    (ii) Hybrid seeds have to be produced year after year.

  • 2)

    (a) A garden pea plant bearing terminal, violet flowers, when crossed with another pea plant bearing axial, violet flowers produced axial, violet flowers in the ratio of 3 : 1.
    Work out the cross showing the genotypes of the parent pea plants and their progeny.
    (b) Name and state the law that can be derived from this cross and not from a mohohybrid cross.

  • 3)

    Why is aerobic degradation more important than anaerobic degradation for the treatment of large volumes of waste water in organic matter. Discuss.

  • 4)

    Answer the following questions related to Down's syndrome.
    (i) When was Down's syndrome first described?
    (ii) What is its frequency in human and does it also occur in other animals?
    (iii) How does Down's syndrome arise?
    (iv) Related it with chromosome dysfunctions.

  • 5)

    Mukta visits a dairy farm near her locality to buy milk for her household. While, waiting there for her turn, she noticed that one of the member of the farm was injecting something into the cow before milking. She was very curious and discussed her queries with her friend (a biology expert) 
    (i) What did the injection contain?
    (ii) Why is this injection administered to the cow?
    (iii) State any two methods of herd improvements.
    (iv) What values are shown by Mukta?

CBSE 12th Standard Biology Subject HOT Questions 5 Marks Questions 2021 Part - I - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    (a) Draw a labelled diagram of L.S. of an embryo of grass (any six labels).
    (b) Give reason for each of the following:
    (i) Anthers of angiosperm flowers are described as dithecous.
    (ii) Hybrid seeds have to be produced year after year.

  • 2)

    (a) A garden pea plant bearing terminal, violet flowers, when crossed with another pea plant bearing axial, violet flowers produced axial, violet flowers in the ratio of 3 : 1.
    Work out the cross showing the genotypes of the parent pea plants and their progeny.
    (b) Name and state the law that can be derived from this cross and not from a mohohybrid cross.

  • 3)

    Why is aerobic degradation more important than anaerobic degradation for the treatment of large volumes of waste water in organic matter. Discuss.

  • 4)

    'Sperm donation can help infertile couples' Justify. In Which type of cases, such sperm donation is helpful?

  • 5)

    Answer the following questions related to Down's syndrome.
    (i) When was Down's syndrome first described?
    (ii) What is its frequency in human and does it also occur in other animals?
    (iii) How does Down's syndrome arise?
    (iv) Related it with chromosome dysfunctions.

CBSE 12th Standard Biology Subject HOT Questions 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    (i)Why does DNA replication occur in small replication forks and not in its entire length?
    (ii)Why is DNA replication countinuous and discountinuous in a replication fork?
    (iii)Explain the importance of 'origin of replication' in a replication fork.

  • 2)

    Anthropogenic action can hasten evolution. Explain with the help of a suitable example.

  • 3)

    The study of
    (i) fossils of dinosaurs
    (ii) forelimbs of Cheeta, bat and human
    (ii) thorns of Bougainvillea and tendril of Cucurbita shows that evolution of life forms has indeed taken place on earth. Explain.

  • 4)

    An organic farmer releies on natural predection for controlling plant pests and diseases. Justify giving reasons why this is considered to be holistic approch.

  • 5)

    If implementation of better techniques and new strategies are required to provide more efficient care and assistance to people, then why is there a statutory ban on amniocentesis? Write the use of this technique and give reason to justify the ban.

CBSE 12th Standard Biology Subject HOT Questions 3 Marks Questions 2021 Part - II - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    (i)Why does DNA replication occur in small replication forks and not in its entire length?
    (ii)Why is DNA replication countinuous and discountinuous in a replication fork?
    (iii)Explain the importance of 'origin of replication' in a replication fork.

  • 2)

    In the following figures label the parts responsible for production of new plants

  • 3)

    Which one is advance- external fertilization or internal fertilization? Give reasons in support of your answer.

  • 4)

    Name 'A' and 'B' in the following equations:
    Sugary juice \(\underrightarrow { 'A' } \) Ethanol + H2 O ; Ethanol \(\underrightarrow { Acetobacter\quad aceti } \) B

  • 5)

    What will you do to get your cow crossed artificially by an exotic bull?

CBSE 12th Standard Biology Subject HOT Questions 3 Marks Questions 2021 Part - I - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    (i)Why does DNA replication occur in small replication forks and not in its entire length?
    (ii)Why is DNA replication countinuous and discountinuous in a replication fork?
    (iii)Explain the importance of 'origin of replication' in a replication fork.

  • 2)

    Anthropogenic action can hasten evolution. Explain with the help of a suitable example.

  • 3)

    The study of
    (i) fossils of dinosaurs
    (ii) forelimbs of Cheeta, bat and human
    (ii) thorns of Bougainvillea and tendril of Cucurbita shows that evolution of life forms has indeed taken place on earth. Explain.

  • 4)

    (a) Why do the symptoms of malaria not appear immediately after the entry of sporozoites into the human body,when bitten by female Anopheles? Explain.
    (b) Give the scientific name of the malarial parasite that causes malignant malaria in humans .

  • 5)

    An organic farmer releies on natural predection for controlling plant pests and diseases. Justify giving reasons why this is considered to be holistic approch.

CBSE 12th Standard Biology Subject HOT Questions 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Geitonogamous flowering plants are genetically autogamous, but functionally cross-pollinated. Justify.

  • 2)

    The cell division involved in gamete formation is not of the same type in different organisms.  Justify.

  • 3)

    Why should a breeder need to emasculate a bisexual flower? Mention a condition in a flower, where emasculation is not necessary?

  • 4)

    A haploid organism produces gametes by mitosis.  Does it mean that meiosis never occurs in such organisms? Justify your answer.

  • 5)

    Reptiles and frogs are oviparous animals; yet they differ in certain aspects of reproduction.  Bring out the differences and mention which of the two animals has more advantage in survival.

CBSE 12th Standard Biology Subject HOT Questions 2 Marks Questions 2021 Part - I - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Explain how geitonogamy is functionally similar to cross-pollination and genetically similar to autogamy.

  • 2)

    If you squeeze a seed of orange, you might observe many embryos of different sizes. How is it possible? Explain.

  • 3)

    The cell division involved in gamete formation is not of the same type in different organisms.  Justify.

  • 4)

    Why should a breeder need to emasculate a bisexual flower? Mention a condition in a flower, where emasculation is not necessary?

  • 5)

    A haploid organism produces gametes by mitosis.  Does it mean that meiosis never occurs in such organisms? Justify your answer.

CBSE 12th Standard Biology Subject HOT Questions 2 Marks Questions 2021 Part - II - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Geitonogamous flowering plants are genetically autogamous, but functionally cross-pollinated. Justify.

  • 2)

    Explain how geitonogamy is functionally similar to cross-pollination and genetically similar to autogamy.

  • 3)

    If you squeeze a seed of orange, you might observe many embryos of different sizes. How is it possible? Explain.

  • 4)

    The cell division involved in gamete formation is not of the same type in different organisms.  Justify.

  • 5)

    A haploid organism produces gametes by mitosis.  Does it mean that meiosis never occurs in such organisms? Justify your answer.

CBSE 12th Standard Biology Subject HOT Questions 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    An anther with malfunctioning tapetum often fails to produce viable male gametophyte. Give any one reason. 

  • 2)

    The meiocyte of rice has 24 chromosomes. Write the number of chromosomes in its endosperm.

  • 3)

    In yeast and Amoeba, the parent cell divides to gives rise to two new individual cells.  How does the cell division differ in these two organisms?

  • 4)

    Why are vectors needed for replication of DNA during rDNA technology?

  • 5)

    What would happen if our intestine harbors microbial flora exactly similar to that found in the rumen of cattle?

CBSE 12th Standard Biology Subject HOT Questions 1 Marks Questions 2021 Part - II - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Why is banana considered a good example of parthenocarpy?

  • 2)

    Banana produces fruits, but is propagated only by vegetative means. Why is it so?

  • 3)

    In yeast and Amoeba, the parent cell divides to gives rise to two new individual cells.  How does the cell division differ in these two organisms?

  • 4)

    During reproduction,the chromosome number (2n) reduces to half (n) in the gametes and again the original number (2n) is restored in the offspring.What are the process through which these events take place?

  • 5)

    Why is sharing of injection needles between two individuals not recommended?

CBSE 12th Standard Biology Subject HOT Questions 1 Marks Questions 2021 Part - I - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    The meiocyte of rice has 24 chromosomes. Write the number of chromosomes in its endosperm.

  • 2)

    Why is banana considered a good example of parthenocarpy?

  • 3)

    Banana produces fruits, but is propagated only by vegetative means. Why is it so?

  • 4)

    How are Cucurbita plants different from papaya plants with reference to the flowers they bear?

  • 5)

    Why do the pollen grains of Vallisneria have a mucilaginous covering?

CBSE 12th Standard Biology Subject HOT Questions MCQ Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    A health disorder that results from the deficiency of thyroxine in adults and characterized by (i) a low metabolic rate (ii) increase in body weight and (iii) tendency to retain water in tissue is:

  • 2)

    Residual persistent nucellus is known as

  • 3)

    At the time of shedding, the number of nuclei present in an angiosperm pollen grain is

  • 4)

    The amount of fresh water of the earth frozen as polar or glacial ice is

  • 5)

    A person likely to develop tetanus is immunised by administering:

CBSE 12th Standard Biology Subject HOT Questions MCQ Questions 2021 Part - II - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    Residual persistent nucellus is known as

  • 2)

    At the time of shedding, the number of nuclei present in an angiosperm pollen grain is

  • 3)

    Which of the following is a hermaphrodite?

  • 4)

    The amount of fresh water of the earth frozen as polar or glacial ice is

  • 5)

    Alzheimer disease in humans is associated with the deficiency of

CBSE 12th Standard Biology Subject HOT Questions MCQ Questions 2021 Part - I - by Shweta Sharma - Anantapur - May 28, 2021 - View & Read

  • 1)

    A health disorder that results from the deficiency of thyroxine in adults and characterized by (i) a low metabolic rate (ii) increase in body weight and (iii) tendency to retain water in tissue is:

  • 2)

    Residual persistent nucellus is known as

  • 3)

    The amount of fresh water of the earth frozen as polar or glacial ice is

  • 4)

    A person likely to develop tetanus is immunised by administering:

  • 5)

    Alzheimer disease in humans is associated with the deficiency of

CBSE 12th Standard Biology Subject Microbes in Human Welfare Ncert Exemplar 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Write a note on fermentation by microbes and its applications.

  • 2)

    In which way have microbes played a major role in controlling diseases caused by harmful bacteria?

  • 3)

    Choose any three microbes, from the following, which are suited for organic farming which is in great demand these days for various reasons. Mention one application of each one chosen.
    Mycorrhiza, Monasus, Anabaena, Rhizobium, Methanobacterium, Trichoderma

  • 4)

    'Determination of Biological Oxygen Demand (BOD) can help in suggesting the quality of a water body'. Explain.

  • 5)

    Explain how are microbes important for humans.

CBSE 12th Standard Biology Subject Microbes in Human Welfare Ncert Exemplar 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    What is the role of microbes in sewage treatment plant?

  • 2)

    Explain why some microorganisms are called biofertilizers.Give two examples.

  • 3)

    What are methanogens? How do they help to generate biogas?

  • 4)

    What are methanogens? Name the animals in which methanogens occur and the role they play there

  • 5)

    In which way have microbes played a major role in controlling diseases caused by harmful bacteria?

CBSE 12th Standard Biology Subject Microbes in Human Welfare Ncert Exemplar 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Why is distillation required for producing certain alcoholic beverages?

  • 2)

    Name the scientists who were credited for showing the role of Penicillin as an antibiotic.

  • 3)

    What would have happened if antibiotics were not discovered?

  • 4)

    Why is distillation required for producing certain alcoholic drinks?

  • 5)

    Name any two species of fungus, which are used in the manufacturing of antibiotics.

CBSE 12th Standard Biology Subject Microbes in Human Welfare Ncert Exemplar 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    What are fermentors?

  • 2)

    Why do we prefer to call secondary wastewater treatment as biological treatment?

  • 3)

    Name the states involved in Ganga action

  • 4)

    What would happenif our interstine harbours microbial flora exactly similar to that found in the rumen of cattle?

  • 5)

    Why is distillation required for producing certain alcoholic beverages?

CBSE 12th Standard Biology Subject Microbes in Human Welfare Ncert Exemplar MCQ Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    In fermentation of dough which is the main gas produced?

  • 2)

    What would happen if oxygen availability to activated sludge flocs is reduced?

  • 3)

    Mycorrhiza does not help the host plant in:

  • 4)

    Methanogens do not produce

  • 5)

    Activated sludge should have the ability to settle quickly so that it can

CBSE 12th Standard Biology Subject Microbes in Human Welfare Ncert Exemplar MCQ Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Bio fertilisers include:

  • 2)

    Methanogens, growing anaerobically on cellulosic material, produce

  • 3)

    In fermentation of dough which is the main gas produced?

  • 4)

    The residue left after methane production from cattle dung is

  • 5)

    Activated sludge should have the ability to settle quickly so that it can

CBSE 12th Standard Biology Subject Environmental Issues Ncert Exemplar 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Explain how biodiversity is important for human.

  • 2)

    Since the origin of life on earth, there were five episodes of mass extinction of species.
    (i)   How is the 'Sixth Extinction', presently n progress, different from the previous episodes?
    (ii)  Who is mainly responsible for the 'Sixth Extinction'?
    (iii) Lis any four points that can help to overcome this disaster.

  • 3)

    Write a note on cultural and religious importance of biodiversity.

  • 4)

    Express your opinion on removal of tribal people out of forest due to developmental activities in the forest.

  • 5)

    The following graph shows the species-area relationship. Answer the following question as directed.

    (i) Name the naturalist who studied the kind of relationship shown in the graph. Write the observation made by him.
    (ii) Write the situations as discovered by the ecologist when the value of Z (*slope of the line) lies between (a) 0.1 and 0.2 (b) 0.6 and 1.2. What does Z stand for?
    (iii) When would the slope of the line 'B' become steeper?

CBSE 12th Standard Biology Subject Environmental Issues Ncert Exemplar 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Human benefits from diversity of life. Give two examples.

  • 2)

    Since the origin of life on earth, there were five episodes of mass extinction of species.
    (i)   How is the 'Sixth Extinction', presently n progress, different from the previous episodes?
    (ii)  Who is mainly responsible for the 'Sixth Extinction'?
    (iii) Lis any four points that can help to overcome this disaster.

  • 3)

    Write a note on cultural and religious importance of biodiversity.

  • 4)

    Express your opinion on removal of tribal people out of forest due to developmental activities in the forest.

  • 5)

    The following graph shows the species-area relationship. Answer the following question as directed.

    (i) Name the naturalist who studied the kind of relationship shown in the graph. Write the observation made by him.
    (ii) Write the situations as discovered by the ecologist when the value of Z (*slope of the line) lies between (a) 0.1 and 0.2 (b) 0.6 and 1.2. What does Z stand for?
    (iii) When would the slope of the line 'B' become steeper?

CBSE 12th Standard Biology Subject Environmental Issues Ncert Exemplar 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Give the expanded from of DDT. Why is it necessary to remove sulphur from petroleum products?

  • 2)

    In the textbox you came across three mile Island Chernbyl disaster associated with accidental lakage of radioactive wasters. In india we had Bhopal gas tragedy.Name the chemical associated with it.

  • 3)

    What is the raw material for polyblend?

  • 4)

    Blends of polyblend and bitumen, when used help to increase the life of roads by a factor of three. What is the reason?

  • 5)

    Is it true that if the dissolved oxygen drops to zero, the water will become septic. Give an example which could lower the dissolved oxygen content of an quatic body

CBSE 12th Standard Biology Subject Environmental Issues Ncert Exemplar 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Give the expanded from of DDT. Why is it necessary to remove sulphur from petroleum products?

  • 2)

    It is a common practise to undertake desiliting of the overhead water tanks.What is the possible source of silt that gets deposited in the water tanks?

  • 3)

    What is the raw material for polyblend?

  • 4)

    Blends of polyblend and bitumen, when used help to increase the life of roads by a factor of three. What is the reason?

  • 5)

    Is it true that if the dissolved oxygen drops to zero, the water will become septic. Give an example which could lower the dissolved oxygen content of an quatic body

CBSE 12th Standard Biology Subject Environmental Issues Ncert Exemplar MCQ Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    More than 70% of world's fresh water is contained in

  • 2)

    Which one of the following statements pertaining to pollutants is correct?

  • 3)

    In a coal fired power plant electrostatic precipitators are installed to control emission of

  • 4)

    Ozone is spread in the swimming pool because

  • 5)

    Which one of the following is the correct percentage of the two green house gases that contribute to the total global warming?

CBSE 12th Standard Biology Subject Environmental Issues Ncert Exemplar MCQ Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    What is the main cause for the extinction of some species in a tropical forest?

  • 2)

    Read the two statements A and B
    Statement A: Diversity observed in the entire geographical area is called gamma diversity.
    Statement B: Biodiversity decrease from high altitude to low altitude, Identify the correct choice from these given below:

  • 3)

    A taxon which is facing an extremely high risk of extinction in the wild in immediate future is known as

  • 4)

    Which was the first National park established in India?

  • 5)

    Which of the following forests is known as the 'lungs of the planet Earth'?

CBSE 12th Standard Biology Subject Biotechnology Principles and Processes Ncert Exemplar 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Mention three uses of PCR.

  • 2)

    Draw a labelled sketch of sparged-stirred tank bioreactor. Write its application.

  • 3)

    Agrobacterium tumifaciens is a soil bacterium; known as a plant pathogen as well a plasmid vector for plant transformation (genetic engineering). Enlist other bacterial plant pathogens or their relatives that have widely used in agriculture and food production.

  • 4)

    Bacteriophages are virus infecting bacteria, that are used as vectors because of their high copy number.
    Lambda phage is a non-contractile bacteriophage used as vector that follows two life cycle, lysogenic and lytic. Explain, both the life cycles with the help of a diagram

  • 5)

    (i) A bacterial cell is shown in the figure given below. Label the part 'A' and 'B'. Also mention the use of part 'A' in rDNA technology.

    (ii) Suppose a linear DNA fragment and a plasmid has three restriction sites for Eco RI. How many fragments will be produced from linear DNA and plasmid respectively.

CBSE 12th Standard Biology Subject Biotechnology Principles and Processes Ncert Exemplar 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    A schematic representation of Polymerase Chain Reaction (PCR) up to the extension stage is given below. Give answers of the following questions.

    (i) Name the process A.
    (ii) Identify B
    (iii) Identify C and mention its importance in PCR. 

  • 2)

    How bacterial cells are made competent to take up DNA?

  • 3)

    Draw a labelled sketch of sparged-stirred tank bioreactor. Write its application.

  • 4)

    Agrobacterium tumifaciens is a soil bacterium; known as a plant pathogen as well a plasmid vector for plant transformation (genetic engineering). Enlist other bacterial plant pathogens or their relatives that have widely used in agriculture and food production.

  • 5)

    Bacteriophages are virus infecting bacteria, that are used as vectors because of their high copy number.
    Lambda phage is a non-contractile bacteriophage used as vector that follows two life cycle, lysogenic and lytic. Explain, both the life cycles with the help of a diagram

CBSE 12th Standard Biology Subject Biotechnology Principles and Processes Ncert Exemplar 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    What is meant by gene cloning?

  • 2)

    You have created a recombinant DNA molecule by ligating a gene to a plasmid vector. By mistake, your friend adds exonuclease enzyme to the tube containing the recombinant DNA. How will your experiment get affected as you plan to go transformation now?

  • 3)

    A mixture of fragmented DNA was electrophoresed in an agarose gel. After staining the gel with ethidium bromide, no DNA bands were observed. What could be the reason?

  • 4)

    (i) How are recombinant vectors created? 
    (ii) For creating one recombinant vector only one type of restriction endonuclease is required. Give reason.

  • 5)

    What would happen if you grow a recombinant in a bioreactor but forget to add antibiotic to the medium in which the recombinant is growing?

CBSE 12th Standard Biology Subject Biotechnology Principles and Processes Ncert Exemplar 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    A plasmid DNA and a linear DNA (both of the same size) have one site for a restriction endonuclease. When cut and separated on agarose gel electrophoresis, plasmid shows one DNA band, while the linear DNA shows two fragments. Explain.

  • 2)

    While carrying out a PCR, 'denaturation' step was missed. What will be its effect on the process?

  • 3)

    What is meant by gene cloning?

  • 4)

    You have created a recombinant DNA molecule by ligating a gene to a plasmid vector. By mistake, your friend adds exonuclease enzyme to the tube containing the recombinant DNA. How will your experiment get affected as you plan to go transformation now?

  • 5)

    Give the name of the type of bioreactor shown. Write the purpose for which it is used.

CBSE 12th Standard Biology Subject Biotechnology Principles and Processes Ncert Exemplar 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    How is copy number of the plasmid vector related to yield of recombinant protein?

  • 2)

    Would you choose an exonuclease for producing a recombinant DNA molecule?

  • 3)

    What does 'competent' refer to, in competent cells used in transformation experiment?

  • 4)

    What is the significance of adding proteases at the time of isolation of genetic material (DNA)?

  • 5)

    Name a recombinant vaccine that is currently being used in vaccination pro-grammes

CBSE 12th Standard Biology Subject Biotechnology Principles and Processes Ncert Exemplar 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    What does 'Hind' and 'III' refer to in the enzyme 'Hind III'?

  • 2)

    How is copy number of the plasmid vector related to yield of recombinant protein?

  • 3)

    Would you choose an exonuclease for producing a recombinant DNA molecule?

  • 4)

    What does 'competent' refer to, in competent cells used in transformation experiment?

  • 5)

    What is the significance of adding proteases at the time of isolation of genetic material (DNA)?

CBSE 12th Standard Biology Subject Biotechnology Principles and Processes Ncert Exemplar MCQ Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Significance of 'heat-shock' method in bacterial transformations is to facilitate:

  • 2)

    Which of the following bacteria is not a source of restriction endonuclease?

  • 3)

    Which of the following steps are catalysed by Taq polymerase in a PCR reaction?

  • 4)

    A bacterial cell was transformed with a recombinant DNA that was generated using a human gene. However, the transformed cells did not produce the desired protein. Reasons could be:

  • 5)

    Which of the following should be chosen for best yield if one were to produce a recombinant protein in large amounts?

CBSE 12th Standard Biology Subject Biotechnology Principles and Processes Ncert Exemplar MCQ Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Significance of 'heat-shock' method in bacterial transformations is to facilitate:

  • 2)

    The role of DNA ligase in the construction of a recombinant DNS molecule is:

  • 3)

    Which of the following bacteria is not a source of restriction endonuclease?

  • 4)

    Which of the following steps are catalysed by Taq polymerase in a PCR reaction?

  • 5)

    Which of the following should be chosen for best yield if one were to produce a recombinant protein in large amounts?

CBSE 12th Standard Biology Subject Biodiversity and Conservation Ncert Exemplar 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Explain briefly the 'rivet popper hypothesis' of Paul Ehrlich.

  • 2)

    Since October 02, 2014 'Swachh Bharat Abhiyan' has been launched in our country.
    (i) Write your views on this initiative giving justification.
    (ii) As a biologist name two problems that you may face while implementing the programme in your locality.
    (iii) Suggest two remedial methods to overcome three problems

  • 3)

    Since October 02, 2014 'Swachh Bharat Abhiyan' has been launched in our country.
    (i) Write your views on this initiative giving justification.
    (ii) As a biologist name two problems that you may face while implementing the programme in your locality.
    (iii) Suggest two remedial methods to overcome three problems

  • 4)

    The relation between species richness and area for a wide variety of taxa turns out to be a rectangular hyperbola. Give a brief explanation.

  • 5)

    Describe the consumptive use value of biodiversity as food, drugs and medicines, fuel and fibre with suitable examples.

CBSE 12th Standard Biology Subject Biodiversity and Conservation Ncert Exemplar 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Since October 02, 2014 'Swachh Bharat Abhiyan' has been launched in our country.
    (i) Write your views on this initiative giving justification.
    (ii) As a biologist name two problems that you may face while implementing the programme in your locality.
    (iii) Suggest two remedial methods to overcome three problems

  • 2)

    The relation between species richness and area for a wide variety of taxa turns out to be a rectangular hyperbola. Give a brief explanation.

  • 3)

    Describe the consumptive use value of biodiversity as food, drugs and medicines, fuel and fibre with suitable examples.

  • 4)

    How can you as an individual, prevent the loss of biodiversity?

  • 5)

    Though the conflict between humans and wildlife started with the evolution of man, the intensity of conflict has increased due to the activities of modern man. Justify your answer with suitable examples.

CBSE 12th Standard Biology Subject Biodiversity and Conservation Ncert Exemplar 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Explain as to how protection of diversity hot spots alone can reduce up to 30% of the current rate of species extinction.

  • 2)

    How does species diversity differ from ecological diversity?

  • 3)

    Name any one greenhouse gas and its possible source of production on a large scale. What are the harmful effects of it?

  • 4)

    How have human activities caused desertification? Explain

  • 5)

    Increased levels of atmosphere CO2 result in the 'greenhouse effect' and thus global warming.The graph shows the effect of these changes on photosynthesis.
    What do you infer about the effect of CO2 and temperature on the rate of photosynthesis in plants?

CBSE 12th Standard Biology Subject Biodiversity and Conservation Ncert Exemplar 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    What are characteristics that make a community stable?

  • 2)

    What could have triggered mass extinction of species in the past?

  • 3)

    What does 'red' indicate in the IUCN red list (2004)?

  • 4)

    The diagram given below shows a river and the types of land uses on two sides of the river in a countryside.

    The water quality of the river was studied by measuring the amount of dissolved oxygen and ammonia in the water, collected at sites X, Y and Z. The result is presented in the table below:

    Site Dissolved oxygen cm3/liter Ammonia(ppm)
    X 8.9 0.02
    Y 0.3 0.62
    Z 1.6 5.30

    (i) Explain why site Y has the lowest content of dissolved oxygen
    (ii) Why are very few fishes found at site 'Z'?
    (iii) Which organism will thrive just after site Z?

  • 5)

    The gradual increase in the temperature of the world is cause of major climatic changes. These climatic changes affect the different aspects of human physiology. Explain the impact of climate change causing various human diseases with the help of flowchart

CBSE 12th Standard Biology Subject Biodiversity and Conservation Ncert Exemplar 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    List any two major causes other than anthropogenic causes of the loss of biodiversity.

  • 2)

    What are sacred groves? Discuss their role in biodiversity conservation.

  • 3)

    Suggest a place, where one can go to study coral reefs, mangrove vegetation and estuaries.

  • 4)

    What is co-extinction? Explain with a suitable example?

  • 5)

    How did pollution of environment start?

CBSE 12th Standard Biology Subject Biodiversity and Conservation Ncert Exemplar 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    What criteria should one use in categorising a spacies as threatened?

  • 2)

    What could be the possible explanation for greater vulnerability of amphibians to extinction as compared to other animal groups?

  • 3)

    How do scientists explain the total number of species on earth?

  • 4)

    List any two major causes other than anthropogenic causes of the loss of biodiversity.

  • 5)

    What are quantitative pollutants?

CBSE 12th Standard Biology Subject Biodiversity and Conservation Ncert Exemplar 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    What is the difference between endemic and exotic species?

  • 2)

    Is it true that there is more solar energy available in the tropics? Explain briefly.

  • 3)

    What is expandend form of IUCN?

  • 4)

    Name the types of pollutants according to their natural disposal.

  • 5)

    What are biodegradable pollutants? Give one example

CBSE 12th Standard Biology Subject Biodiversity and Conservation Ncert Exemplar 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    What is Red Data Book?

  • 2)

    What does the term frugivorous mean?

  • 3)

    Define (i) Bioprospecting (ii) Endemism.

  • 4)

    What are the 5 main types of pollution?

  • 5)

    Name the types of pollutants according to their natural disposal.

CBSE 12th Standard Biology Subject Biodiversity and Conservation Ncert Exemplar MCQ Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    More than 70% of world's fresh water is contained in

  • 2)

    Which one of the following statements pertaining to pollutants is correct?

  • 3)

    In a coal fired power plant electrostatic precipitators are installed to control emission of

  • 4)

    Which one of the following is the correct percentage of the two green house gases that contribute to the total global warming?

  • 5)

    A lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this.
    (a) lots of urea and phosphate fertilizers were used in the crops in the vicinity
    (b) the area was sprayed with DDT by an aircraft
    (c) the lake water turned green and stinky
    (d) phytoplankton populations in the lake declined initially thereby greatly reducing photosynthesis
    Which two of the above were main reasons of fish mortality in the lake?

CBSE 12th Standard Biology Subject Biodiversity and Conservation Ncert Exemplar MCQ Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    In 1984, the Bhopal gas tragedy took place because methyl isocyanate

  • 2)

    Common indicator organism of water pollution is

  • 3)

    In a coal fired power plant electrostatic precipitators are installed to control emission of

  • 4)

    A genetically engineered microorganism used successfully in bioremediation of oil spills is a species of

  • 5)

    A lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this.
    (a) lots of urea and phosphate fertilizers were used in the crops in the vicinity
    (b) the area was sprayed with DDT by an aircraft
    (c) the lake water turned green and stinky
    (d) phytoplankton populations in the lake declined initially thereby greatly reducing photosynthesis
    Which two of the above were main reasons of fish mortality in the lake?

CBSE 12th Standard Biology Subject Ecosystem Ncert Exemplar 5 Mark Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Write a short note on pyramid of numbers and pyramid of biomass.

  • 2)

    "The energy flow in the ecosystem follows the second law of thermodynamics". Explain.

  • 3)

    What will happen to an ecosystem if
    (a) All producers are removed.
    (b) All organisms of herbivore level are eliminated and
    (c) All top carnivore population is removed.

  • 4)

    Give two examples of artificial or man-made ecosystems. List the salient features by which they differ from natural ecosystems.

  • 5)

    The biodiversity increases when one moves from the pioneer to the climax stage. what could be the explanation?

CBSE 12th Standard Biology Subject Ecosystem Ncert Exemplar 5 Mark Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    A farmer harvests his crop and expresses his harvest in three different ways:
    (a) I have harvested 10 quintals of wheat.
    (b) I have harvested 10 quintals of wheat today in one acre land.
    (c) I have harvested 10 quintals of wheat in one acre of land, 6 months after sowing.
    Do the above statements mean one and the same thing. If your answer is "Yes", give reasons. And if your answer is "No", explain the meaning of each expression.

  • 2)

    Justify the following statement in terms of ecosystem dynamics."Nature tends to increase the gross primary productivity, while man tends to increase the gross primary productivity, while man tends to increase the net primary-productivity".

  • 3)

    Which of the following ecosystem will be more productive in term of primary productivity? Justify your answer.

  • 4)

    What will happen to an ecosystem if
    (a) All producers are removed.
    (b) All organisms of herbivore level are eliminated and
    (c) All top carnivore population is removed.

  • 5)

    Give two examples of artificial or man-made ecosystems. List the salient features by which they differ from natural ecosystems.

CBSE 12th Standard Biology Subject Ecosystem Ncert Exemplar 3 Mark Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Explain why ecological succession will be faster in a forest devastated by fire than on a bare rock? Also, compare succession in case of an abandoned land after floods with that on a bare rock?

  • 2)

    (i) Define pioneer species.
    (ii) Among bryophytes, lichens and fern, which one is a pioneer species in a xeric succession? And why?

  • 3)

    Nutrients are essential for growth of producers, i.e. for the primary productivity of the ecosystem. The inorganic elements required by the plants present in the soil in the form of minerals are called mineral elements or mineral nutrients. Some of these mineral elements are nitrogen, sulphur, calcium, iron and manganese.State the deficiency symptoms of all elements mentioned above

  • 4)

    Decomposition is the process of breaking down of complex organic matter into inorganic substances. Different steps involved in the process of decomposition are fragmentation, leaching, catabolism, humification and mineralisation. Fragmentation is the breakdown of detritous (dead remains and faecal matter)with the help of detrivores e.g.earthworm.With reference to the above paragraph, answer the questions that follow.
    (i) State the phylum and scientific name of earthworm.
    (ii) The process of fragmentation involves the coordinated function of its digestive and excretory system.Mention the location of oesophagus, integumentary nephridia, typhlosole and gizzard in the earthworm.
    (iii) Why does an earthworm die in sunlight?

  • 5)

    According to the 10% law given by Lindeman, only 10% of the energy is transferred to the next trophic level.
    (i) Name the process by which an organism produces energy.
    (ii) What is the most common substrate used in this pathway?
    (iii) Which biomolecule is also known as energy currency of the cell?

CBSE 12th Standard Biology Subject Ecosystem Ncert Exemplar 3 Mark Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    (i) Define pioneer species.
    (ii) Among bryophytes, lichens and fern, which one is a pioneer species in a xeric succession? And why?

  • 2)

    Nutrients are essential for growth of producers, i.e. for the primary productivity of the ecosystem. The inorganic elements required by the plants present in the soil in the form of minerals are called mineral elements or mineral nutrients. Some of these mineral elements are nitrogen, sulphur, calcium, iron and manganese.State the deficiency symptoms of all elements mentioned above

  • 3)

    Decomposition is the process of breaking down of complex organic matter into inorganic substances. Different steps involved in the process of decomposition are fragmentation, leaching, catabolism, humification and mineralisation. Fragmentation is the breakdown of detritous (dead remains and faecal matter)with the help of detrivores e.g.earthworm.With reference to the above paragraph, answer the questions that follow.
    (i) State the phylum and scientific name of earthworm.
    (ii) The process of fragmentation involves the coordinated function of its digestive and excretory system.Mention the location of oesophagus, integumentary nephridia, typhlosole and gizzard in the earthworm.
    (iii) Why does an earthworm die in sunlight?

  • 4)

    Due to uncontrolled excessive hunting, the population of tigers in a forest has become zero.Discuss the long-term effects of this situation on the population of deer in that forest.

  • 5)

    Three food chains are shown below:
      1. Grass\(\rightarrow\)Deer \(\rightarrow\) Tiger
      2. Tree \(\rightarrow\) Beetle \(\rightarrow\) Bacteria
      3. Flowering plant \(\rightarrow\) Butterfly \(\rightarrow\) Bird
    They can be represented by the three pyramids of numbers P, Q and R below:

    Write the correct combination that correctly matches food chains and pyramids.

CBSE 12th Standard Biology Subject Ecosystem Ncert Exemplar 2 Mark Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    What could be the reason for the fast rate of decomposition in the tropics?

  • 2)

    A part from plants and animals,microbes form a permanent biotic component in an ecosystem.While plants have been referred to as autorophs and animals a sheterotrophs,How do microbes fulfil their energy requirements?

  • 3)

    Flow of energy through various trophic levels in an ecosystem is unidirectional and non-cyclic. Explain.

  • 4)

    In relation to energy transfer in the ecosystem, explain the statement "10kg of deer's meat is equivalent to 1kg of lion's flesh".

  • 5)

    Primary productivity varies from ecosystem to ecosystem. Explain.

CBSE 12th Standard Biology Subject Ecosystem Ncert Exemplar 2 Mark Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    What could be the reason for the fast rate of decomposition in the tropics?

  • 2)

    A part from plants and animals,microbes form a permanent biotic component in an ecosystem.While plants have been referred to as autorophs and animals a sheterotrophs,How do microbes fulfil their energy requirements?

  • 3)

    In relation to energy transfer in the ecosystem, explain the statement "10kg of deer's meat is equivalent to 1kg of lion's flesh".

  • 4)

    Primary productivity varies from ecosystem to ecosystem. Explain.

  • 5)

    Sometimes due to biotic/abiotic factor the climax remain in a particular seral stage (pre climax) without reaching climax. Do you agree with this statement? If yes give a suitable example.

CBSE 12th Standard Biology Subject Ecosystem Ncert Exemplar 1 Mark Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Justy the pitcher plant as a producer.

  • 2)

    Name any two organisms which can occupy more than one trophic level in an ecosystem.

  • 3)

    Among bryophytes, lichen  s and ferns,which one is a pioneer species in a xeric succession?

  • 4)

    Why is the rate of assimilation of energy at the herbivore level called secondary productivity?

  • 5)

    What is common to earthworm,soil mites and dung beetles in an ecosystem?

CBSE 12th Standard Biology Subject Ecosystem Ncert Exemplar 1 Mark Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    How much of the net primary productivity of a terrestial ecosystem is eaten and digested by herbivores?

  • 2)

    Name an organism found as secondary carnivore in aquatic ecosystem.

  • 3)

    What does the base tier of the ecological pyramid  represent?

  • 4)

    What does the base tier of the ecological pyramid represent?

  • 5)

    Under what conditions would a particular stage in the process of succession revert back to an earlier stage?

CBSE 12th Standard Biology Subject Ecosystem Ncert Exemplar MCQ Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Nutrient enrichment of a lake will cause

  • 2)

    Which of the ecological pyramid is always straight?

  • 3)

    In an ecosystem, the cycling of nutrients is known as

  • 4)

    In ecological succession, the climax community is best recognised by the following state

  • 5)

    Of the total incident solar radiation the proportion of PAR is

CBSE 12th Standard Biology Subject Ecosystem Ncert Exemplar MCQ Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Which one of the following pairs is mismatched?

  • 2)

    Which one of the following is not used for construction of ecological pyramids?

  • 3)

    In an ecosystem, the cycling of nutrients is known as

  • 4)

    In ecological succession, the climax community is best recognised by the following state

  • 5)

    Of the total incident solar radiation the proportion of PAR is

CBSE 12th Standard Biology Subject Organisms and Populations Ncert Exemplar 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    The following diagrams are the age pyramids of different populations. Comment on the status of these populations.

  • 2)

    Comment on the growth curve given below.

  • 3)

    Give one example for each of the following:
    (i) Eurythermal plant species_________.
    (ii) A hot water spring organism _________.
    (iii) An organism seen in deep ocean trenches _________.
    (iv) An organism seen in composite pit_________.
    (v) A parasitic angiosperm _________.
    (vi) A stenothermal plant species _________.
    (vii) Soil organism _________.
    (viii)  A benthic animal Soil organism _________.
    (ix) Antifreeze compound seen in antarctic fish Soil organism_________.
    (x) An organism which can conform Soil orga.niam_________.

  • 4)

    Comment on the following figures 1,2 and 3 : A,B,C,D,G,P,Q,R,S are species

  • 5)

    Does light factor affect the distribution of organisms? Write a brief note giving suitable examples of either plants or animals.

CBSE 12th Standard Biology Subject Organisms and Populations Ncert Exemplar 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    The following diagrams are the age pyramids of different populations. Comment on the status of these populations.

  • 2)

    Comment on the growth curve given below.

  • 3)

    Give one example for each of the following:
    (i) Eurythermal plant species_________.
    (ii) A hot water spring organism _________.
    (iii) An organism seen in deep ocean trenches _________.
    (iv) An organism seen in composite pit_________.
    (v) A parasitic angiosperm _________.
    (vi) A stenothermal plant species _________.
    (vii) Soil organism _________.
    (viii)  A benthic animal Soil organism _________.
    (ix) Antifreeze compound seen in antarctic fish Soil organism_________.
    (x) An organism which can conform Soil orga.niam_________.

  • 4)

    Comment on the following figures 1,2 and 3 : A,B,C,D,G,P,Q,R,S are species

  • 5)

    Does light factor affect the distribution of organisms? Write a brief note giving suitable examples of either plants or animals.

CBSE 12th Standard Biology Subject Organisms and Populations Ncert Exemplar 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Give one example for each of the following:
    (a) Migratory animal    
    (b) Predator animal    
    (c) Phytophagous animals    
    (d) Camouflaged animal    
    (e) Chemical defense agent.

  • 2)

    Study the graph given below and answer the questions that follow.

    (i) Write the status of food and space in the curves A and B.
    (ii) In the absence of predators, which one of the two curves would appropriately depict the prey population?
    (iii)Time has been shown on X-axis and there is a parallel dotted line above it. Give the significance of this dotted line.

  • 3)

    Explain the S-shaped pattern of population growth. How is J-shaped pattern different from it and why?

  • 4)

    Why are coral reefs not found in the regions from West Bengal to Andhra Pradesh but are found in Tamil Nadu and on the East coast of India?

  • 5)

    Why do all the fresh water organisms have contractile vacuoles whereas majority of marine organisms lack them?

CBSE 12th Standard Biology Subject Organisms and Populations Ncert Exemplar 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Give one example for each of the following:
    (a) Migratory animal    
    (b) Predator animal    
    (c) Phytophagous animals    
    (d) Camouflaged animal    
    (e) Chemical defense agent.

  • 2)

    An individual and a population has certain characteristics.  Name these attributes with definitions.

  • 3)

    A population of paramoecium caudatum was grown in a culture medium. After 5 days, the culture medium became over-crowed wth paramoecium and had depleted nutrients. What will happen to the population and what type of growth curve will the population attain? Draw the growth curve.

  • 4)

    Study the graph given below and answer the questions that follow.

    (i) Write the status of food and space in the curves A and B.
    (ii) In the absence of predators, which one of the two curves would appropriately depict the prey population?
    (iii)Time has been shown on X-axis and there is a parallel dotted line above it. Give the significance of this dotted line.

  • 5)

    Study the population growth curve in the graph given below and answer the following questions.

    (i) Identify the growth curves 'A' and 'B'.
    (ii) Which one of them is considered a more realistic one and why?
    (iii) If \(\frac { dN }{ dt } =rN(\frac { K-N }{ K } )\) is the equation of the curve B, what does K stand for?
    (iv) What is symbolised by N?

CBSE 12th Standard Biology Subject Organisms and Populations Ncert Exemplar 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Define 'zero population growth rate'.  Draw an age pyramid for the same.

  • 2)

    If a freshwater fish is placed in an aquarium containing sea water, will the fish be able to survive? Explain giving reasons.

  • 3)

    Why do all the freshwater organisms have contractile vacuoles whereas majority of marine organisms lack them?

  • 4)

    Define heliophytes and sciophytes. Name plant from your locality that is either heliophyte or sciophyte.

  • 5)

    In a pond, we see plants which are free floating, rooted-submerged, rooted-emergent, rooted with floating leaves. Write the type of plant against the following examples:
    (a) Hydrilla        
    (b) Typha
    (c) Nymphaea    
    (d) Lemna
    (e) Vallisneria

CBSE 12th Standard Biology Subject Organisms and Populations Ncert Exemplar 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Define 'zero population growth rate'.  Draw an age pyramid for the same.

  • 2)

    In an aquarium two herbivorous species of fish are living together and feeding on phytoplanktons.  As per the Gause's principle, one of the species is to be eliminated in due course of time, but both are surviving well in the aquarium.  Give possible reasons.

  • 3)

    Why do all the freshwater organisms have contractile vacuoles whereas majority of marine organisms lack them?

  • 4)

    Define heliophytes and sciophytes. Name plant from your locality that is either heliophyte or sciophyte.

  • 5)

    Why do submerged plants receive weaker illuminations than exposed floating plants in a lake?

CBSE 12th Standard Biology Subject Organisms and Populations Ncert Exemplar 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    An association between two individuals or populations where both are benefitted and where neither can survive without the other is

  • 2)

    What would be the per cent growth or birth rate pe individual per hour for the same population mentioned in the question (Question 10 at Page 95)?

  • 3)

    A population has more young individuals compared to the older individuals. What would be the status of the population after some years?

  • 4)

    What parameters are used for tiger census in our country's national parks sanctuaries?

  • 5)

    Which of the following would necessarily decrease the density of a population in a given habitat?

CBSE 12th Standard Biology Subject Organisms and Populations Ncert Exemplar 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    What is interaction between two species called?

  • 2)

    What will happen to a well-growing herbaceous plant in the forests, it it is transplanted outside the forest in a park?

  • 3)

    Species that can tolerate narrow range of temperature are called ------------

  • 4)

    What are eurythermic species ?

  • 5)

    Define stenohaline species.

CBSE 12th Standard Biology Subject Organisms and Populations Ncert Exemplar MCQ Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    An association between two individuals or populations where both are benefitted and where neither can survive without the other is

  • 2)

    If in a population, natality is balanced by mortality then there will be

  • 3)

    What would be the per cent growth or birth rate pe individual per hour for the same population mentioned in the question (Question 10 at Page 95)?

  • 4)

    A population has more young individuals compared to the older individuals. What would be the status of the population after some years?

  • 5)

    Which of the following would necessarily decrease the density of a population in a given habitat?

CBSE 12th Standard Biology Subject Organisms and Populations Ncert Exemplar MCQ Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    An association between two individuals or populations where both are benefitted and where neither can survive without the other is

  • 2)

    If in a population, natality is balanced by mortality then there will be

  • 3)

    A population has more young individuals compared to the older individuals. What would be the status of the population after some years?

  • 4)

    Which of the following would necessarily decrease the density of a population in a given habitat?

  • 5)

    A protozoan reproduces by binary fission. What will be the number of protozoans in its population after six generations?

CBSE 12th Standard Biology Subject Biotechnology and its Applications Ncert Exemplar 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    List the disadvantages of insulin obtained from the pancreas of slaughtered cows and pigs.

  • 2)

    List the advantages of recombinant insulin.

  • 3)

    What is meant by the term biopesticide? Name and explain the mode of action of a popular bio-pesticide.

  • 4)

    Name the five tools for accomplishing the tasks of recombinant DNA technology. Also mention the function of each tools. 

  • 5)

    Anil's grandfather read in the newspaper about golden rice. Being a farmer, he asked Anil to get more information from his teacher about this rice.Teacher explained to him that it is a new variety of rice which in precursor of vitamin A and his will be useful for rice eating poor population.
    Read the above passage and answer the following questions:
    (i) What is golden rice?
    (ii) Why is it beneficial for rice eating poor population?
    (iii) What values is displayed by Anil's grandfather?

CBSE 12th Standard Biology Subject Biotechnology and its Applications Ncert Exemplar 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    List the disadvantages of insulin obtained from the pancreas of slaughtered cows and pigs.

  • 2)

    List the advantages of recombinant insulin.

  • 3)

    Anil's grandfather read in the newspaper about golden rice. Being a farmer, he asked Anil to get more information from his teacher about this rice.Teacher explained to him that it is a new variety of rice which in precursor of vitamin A and his will be useful for rice eating poor population.
    Read the above passage and answer the following questions:
    (i) What is golden rice?
    (ii) Why is it beneficial for rice eating poor population?
    (iii) What values is displayed by Anil's grandfather?

  • 4)

    Prashant's mother is suffering from a disorder for which doctor suggests her to take insulin injections. But his mother declines as she presumes injection are prepared by slaughtering of animals. Doctor smiled and explained him about the genetically engineered human insulin produced these days. He also convinced her to take injections.
    (i) Name the bacterium that is used to produce human insulin.
    (ii) Name the company that first produced human insulin.
    (iii) Name the disease that is treated by using human insulin.
    (iv) What values are shown by the doctor?

  • 5)

    In a press note, it was mentioned that Kenya wants a share of the sales of a fabric softener that uses enzymes derived from its lake Bogoria. Since past many generations the people of Kenya, attributed mystical powers to its water.
    Scientists found creatures that reside in one of the earth's most inhospitable terrains.
    Another country subsequently obtained the water sample of the lake containing the creatures and their enzyme and cloned them on an industrial scale for textile companies and biodetergent manufacturers.
    (i) What is your interpretation of the above report?
    (iii) What are the values shown by another country?

CBSE 12th Standard Biology Subject Biotechnology and its Applications Ncert Exemplar 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Differentiate between diagnostics and therapeutics. Give one example for each category.

  • 2)

    In a medical case, It was detected that a child is suffering from a genetic disorder due to the deletion of the gene. What remedial measure do you suggest for the treatment of such disorder.

  • 3)

    Correct the following statement giving reasons -
    "The mature insulin molecule consists of three short polypeptide chains".

  • 4)

    A new type of drug, PTC 124, enables translation to continue through the nonsense codon. Trials in mice homozygous for a CFTR allele containing the nonsense codon have found that animals treated with PTC 124 produce normal CFTER protein in their cells. The drug is taken orally and is readily taken up into cells all over the body.
    Using your knowledge of the progress toward successful gene therapy for cystic fibrosis, suggest why PTC 124 could be simpler and more reliable treatment for this disease.

  • 5)

    Consult internet and find out how to make orally active protein pharmaceutical. What is the major problem to be encountered?

CBSE 12th Standard Biology Subject Biotechnology and its Applications Ncert Exemplar 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Differentiate between diagnostics and therapeutics. Give one example for each category.

  • 2)

    In a medical case, It was detected that a child is suffering from a genetic disorder due to the deletion of the gene. What remedial measure do you suggest for the treatment of such disorder.

  • 3)

    Correct the following statement giving reasons -
    "The mature insulin molecule consists of three short polypeptide chains".

  • 4)

    A new type of drug, PTC 124, enables translation to continue through the nonsense codon. Trials in mice homozygous for a CFTR allele containing the nonsense codon have found that animals treated with PTC 124 produce normal CFTER protein in their cells. The drug is taken orally and is readily taken up into cells all over the body.
    Using your knowledge of the progress toward successful gene therapy for cystic fibrosis, suggest why PTC 124 could be simpler and more reliable treatment for this disease.

  • 5)

    Write a short note on biopiracy highlighting the exploitation of developing countries by the developed countries.

CBSE 12th Standard Biology Subject Biotechnology and its Applications Ncert Exemplar 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Discuss briefly how a probe is used in molecule diagnostics.

  • 2)

    Who was first patient, who was given gene therapy? Why was the given treatement recurrent in nature?

  • 3)

    Taking examples from each caligoy, discuss upstream and downstreaming process.

  • 4)

    Define Antigen and Antibody. Name any two diagnostic kits based upon them.

  • 5)

    Elisa technique is based on antigen and antibody interaction. Can this technique be used in the molecular diagnosis of genetic disorder such as phenylketonuria?

CBSE 12th Standard Biology Subject Biotechnology and its Applications Ncert Exemplar 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Gene expression can be controlled with the help of RNA molecule. Explain the method with an example.

  • 2)

    Ignoring traditional knowledge can prove costly in the area of biological patening. Justify.

  • 3)

    Highlight any four areas where genetic modification of plants has been useful.

  • 4)

    What is a recombinant DNA vaccine? Give two examples.

  • 5)

    Elisa technique is based on antigen and antibody interaction. Can this technique be used in the molecular diagnosis of genetic disorder such as phenylketonuria?

CBSE 12th Standard Biology Subject Biotechnology and its Applications Ncert Exemplar 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Many proteins are secreted in their inactive form. This is also true of many toxic proteins produced by microorganisms. Explain how the mechanism is useful for the organisms producing the toxin.

  • 2)

    While creating genetically modified organisms, genetic barriers are not respected. How this can be dangerous in the long run?

  • 3)

    Why has the Indian Parliament cleared the second amendment of the country's patents bill?

  • 4)

    What are the hybridomas?

  • 5)

    Give the name of the source organisms of the gene cry Iac and its target pest.

CBSE 12th Standard Biology Subject Biotechnology and its Applications Ncert Exemplar 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Can a disease be detected before its symptoms appear? Name the principle involved.

  • 2)

    Many proteins are secreted in their inactive form. This is also true of many toxic proteins produced by microorganisms. Explain how the mechanism is useful for the organisms producing the toxin.

  • 3)

    While creating genetically modified organisms, genetic barriers are not respected. How this can be dangerous in the long run?

  • 4)

    Why has the Indian Parliament cleared the second amendment of the country's patents bill?

  • 5)

    What are the hybridomas?

CBSE 12th Standard Biology Subject Biotechnology and its Applications Ncert Exemplar MCQ Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    ADA is an enzyme which is deficient in a genetic disorder SCID. What is the full form of ADA?

  • 2)

    Silencing of a gene could be achieved through the use of:

  • 3)

    \(\alpha\)-I antitrypsin is:

  • 4)

    The trigger for activation of toxin of Bacillus thuringiensis is

  • 5)

    C-peptide of human insulin is

CBSE 12th Standard Biology Subject Biotechnology and its Applications Ncert Exemplar MCQ Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Golden rice is:

  • 2)

    The first clinical gene therapy was done for the treatment of:

  • 3)

    ADA is an enzyme which is deficient in a genetic disorder SCID. What is the full form of ADA?

  • 4)

    Silencing of a gene could be achieved through the use of:

  • 5)

    The trigger for activation of toxin of Bacillus thuringiensis is

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Ncert Exemplar 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    (a) The shift from grain to meat diets creates more demands for cereals. Why?
    (b) A 250 kg cow produces 200 g of protein per day but 250 g of Methylophillus methylotrophus can produce 25 tonnes of protein. Name this emerging area of research. Explain its benefits.

  • 2)

    "Modern methods of breeding animals and plants can alleviate the global food shortage". Comment on the statement and give suitable examples.

  • 3)

    (i) State the objective of animal breeding.
    (ii) List the importance and limitations of inbreeding. How can the limitations be overcome?
    (iii) Give an example of a new breed each of cattle nd poultry.

  • 4)

    Discuss briefly the technology that made us self-sufficient in food production.

  • 5)

    Mutations are beneficial for plant breeding. Taking an example, justify the statement.

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Ncert Exemplar 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    (a) The shift from grain to meat diets creates more demands for cereals. Why?
    (b) A 250 kg cow produces 200 g of protein per day but 250 g of Methylophillus methylotrophus can produce 25 tonnes of protein. Name this emerging area of research. Explain its benefits.

  • 2)

    "Modern methods of breeding animals and plants can alleviate the global food shortage". Comment on the statement and give suitable examples.

  • 3)

    (i) State the objective of animal breeding.
    (ii) List the importance and limitations of inbreeding. How can the limitations be overcome?
    (iii) Give an example of a new breed each of cattle nd poultry.

  • 4)

    Discuss briefly the technology that made us self-sufficient in food production.

  • 5)

    Mutations are beneficial for plant breeding. Taking an example, justify the statement.

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Ncert Exemplar 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    What is the different between pisciculture and Aquaculture? What are the benefits of both kinds of cultures?

  • 2)

    What ingredients you suggest to be added in the following specified culture media?
    (a) Preparation of a semisolid medium
    (b) Preparation of a solid medium
    (c) A culture medium for graving an explant in vitro.

  • 3)

    What will you do to get your cow crossed artificially by an exotic bull?

  • 4)

    Discuss the importance of testing of new plant varieties in a geographically vast country like India.

  • 5)

    'Modern methods of breeding animals and plants can alleviate the global food shortage'. Comment on the statements and give suitable examples.

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Ncert Exemplar 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    What is the different between pisciculture and Aquaculture? What are the benefits of both kinds of cultures?

  • 2)

    What ingredients you suggest to be added in the following specified culture media?
    (a) Preparation of a semisolid medium
    (b) Preparation of a solid medium
    (c) A culture medium for graving an explant in vitro.

  • 3)

    What is the main reason for low milk production in  India? How can it be improved?

  • 4)

    Name the steps represented in the following process.

  • 5)

    'Modern methods of breeding animals and plants can alleviate the global food shortage'. Comment on the statements and give suitable examples.

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Ncert Exemplar 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Life style diseases are increasing alarmingly in India. We are also dealing with large scale malnutrition in the population. Is there any method by which we can address both of these problems together?

  • 2)

    How can we improve the success rate of fertilisation during artificial insemination in animal husbandry programmes?

  • 3)

    What is meant by germplasm collection? What are its benefits?

  • 4)

    Name the improved characteristics of wheat that helped India to achieve green revolution.

  • 5)

    Suggest two features of plants that will prevent insect and pest infestation.

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Ncert Exemplar 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    What is aquaculture? Give an example of an animal that can be multiplied by acquaculture.

  • 2)

    Difference between pisciculture and aquaculture.

  • 3)

    What is the difference between a breed and a species? Give an example for each category.

  • 4)

    Is there any relationship between dedifferentiation and the higher degree of success achieved in plant tissue culture experiments?

  • 5)

    Define the term 'stress' for plants, Discuss briefly the two types of stress encountered by plants.

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Ncert Exemplar 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Why are plants obtained by protoplast culture called somatic hybirds?

  • 2)

    It is easier to culture plants cells in vitro as compared to animal cells. Why?

  • 3)

    Can gamma rays used for crop improvements programmes prove to be harmful for health? Discuss.

  • 4)

    In animal husbandry, if two closely related animals are mated for a few generations, it results in loss of fertility and vigour. Why is it so?

  • 5)

    What are the duties of a veterinary doctor in management of a poultry farm?

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Ncert Exemplar 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Interspecific crosses are rare in nature and intergeneric crosses almost unknown Why?

  • 2)

    It is easier to culture plants cells in vitro as compared to animal cells. Why?

  • 3)

    Can gamma rays used for crop improvements programmes prove to be harmful for health? Discuss.

  • 4)

    Do you know of a man made cereal? Trace, how it was developed?

  • 5)

    What are the duties of a veterinary doctor in management of a poultry farm?

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Ncert Exemplar MCQ Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Given below are a few statements regarding somatic hybridization.Choose the correct statements.
    (i)protoplasts of different cells of the same plant are fused
    (ii)protoplasts from cells of different species can be fused
    (iii)treatment of cells with cellulase and pectinase is mandatory
    (iv)the hybrid protoplast contains characters of only one parental protoplast.

  • 2)

    An explant is:

  • 3)

    The biggest constraint of plant breeding is :

  • 4)

    To isolate protoplast, one needs :

  • 5)

    Which one of the following is a marine fish :

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Ncert Exemplar MCQ Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    The term 'totipotency' refers to the capacity of a:

  • 2)

    Given below are a few statements regarding somatic hybridization.Choose the correct statements.
    (i)protoplasts of different cells of the same plant are fused
    (ii)protoplasts from cells of different species can be fused
    (iii)treatment of cells with cellulase and pectinase is mandatory
    (iv)the hybrid protoplast contains characters of only one parental protoplast.

  • 3)

    Lysine and tryptophan are :

  • 4)

    Micro-propagation is :

  • 5)

    protoplast is:

CBSE 12th Standard Biology Subject Human Health and Disease Ncert Exemplar 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Why do some adolescent start taking drugs?How can this be avoided.

  • 2)

    What is Pulse Polio Programme of  Government of India? What is OPV? Why is it that India is yet to eradicate Pollio.

  • 3)

    What are recombinant DNA vaccines? Give two examples of such vaccines. Discuss their advantages.

  • 4)

    In the given flow diagram, the replication of retrovirus in a host is shown. Observe and answer the following questions.
    (a) fill in (A) and (B)

    b) Why is the virus called retrovirus?
    (c) Can the infected cell survive, while viruses are being replicated and released?

  • 5)

    Represent schematically the life cycle of a malarial parasite.

CBSE 12th Standard Biology Subject Human Health and Disease Ncert Exemplar 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    What is Pulse Polio Programme of  Government of India? What is OPV? Why is it that India is yet to eradicate Pollio.

  • 2)

    Fill in the blanks:
    (i) A drug relieves pain is called_______.
    (ii) Any drink which has caffeine causes_______.
    (iii) ...is derived from the unripe capsules of white poppy_______.
    (iv) Marijuana is obtained from_______.
    (v) The intake of_______.after a normal doze of barbiturates may cause death.
    (vi) L.S.D stands for_______.
    (vii) The chemical named_______.present in Lophophora is hallucinogenic.
    (viii) antibiotics are not effective against_______.
    (ix) The first antibiotic discovered was_______.
    (x) _______.is a source of sex hormones.

  • 3)

    In the given flow diagram, the replication of retrovirus in a host is shown. Observe and answer the following questions.
    (a) fill in (A) and (B)

    b) Why is the virus called retrovirus?
    (c) Can the infected cell survive, while viruses are being replicated and released?

  • 4)

    Represent schematically the life cycle of a malarial parasite.

  • 5)

    Drugs like LSD,barbiturates, amphetamines, etc., are used as medicines to help patients with mental illness. However, excessive doses and abusive usage are harmful. Enumerate the major adverse effects of such drugs in humans.

CBSE 12th Standard Biology Subject Human Health and Disease Ncert Exemplar 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    In which parts of the body of the hosts do the following events in the life cycle of Plasmodium take place? Name both the body part and the host.
    (a) Fertilization   (b) Development of gametocytes   (c) Release of sporozoites  (d) Asexual reproduction.

  • 2)

    Give Reasons for the following statements:
    (a) Neutrophils and macrophages are called soldiers and scavengers of the animal body.
    (b) After consuming alcohol, one should avoid driving.
    (c) Persistent use of corticosteroids is harmful.

  • 3)

    'Prevention is better than cure'. Comment.

  • 4)

    Why is it that during changing weather, one is advised to avoid closed, crowded and air conditioned places like cinema halls, etc?

  • 5)

    Differentiate the following and give examples of each.
    (i) Innate and acquired immunity.
    (ii) Active and passive immunity.

CBSE 12th Standard Biology Subject Human Health and Disease Ncert Exemplar 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    In which parts of the body of the hosts do the following events in the life cycle of Plasmodium take place? Name both the body part and the host.
    (a) Fertilization   (b) Development of gametocytes   (c) Release of sporozoites  (d) Asexual reproduction.

  • 2)

    Give Reasons for the following statements:
    (a) Neutrophils and macrophages are called soldiers and scavengers of the animal body.
    (b) After consuming alcohol, one should avoid driving.
    (c) Persistent use of corticosteroids is harmful.

  • 3)

    Many microbial pathogens enter the gut of humans along with food. What are the preventive barriers to protect the body from such pathogens?

  • 4)

    Why is it that during changing weather, one is advised to avoid closed, crowded and air conditioned places like cinema halls, etc?

  • 5)

    Differentiate the following and give examples of each.
    (i) Innate and acquired immunity.
    (ii) Active and passive immunity.

CBSE 12th Standard Biology Subject Human Health and Disease Ncert Exemplar 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Differentiate between Benign tumour and Malignant Tumour

  • 2)

    Do you Consider passive smoking is more dangerous than active smoking?why?

  • 3)

    Explain any three preventive measures to control microbial infections.

  • 4)

    Many secondary metabolites of plants have medical properties.It is their misuse that creates problems.Justify the statement with an example.

  • 5)

    For an organ transplant, it is advantageous to have an identical twin.why?

CBSE 12th Standard Biology Subject Human Health and Disease Ncert Exemplar 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Do you Consider passive smoking is more dangerous than active smoking?why?

  • 2)

    Explain any three preventive measures to control microbial infections.

  • 3)

    Many secondary metabolites of plants have medical properties.It is their misuse that creates problems.Justify the statement with an example.

  • 4)

    Drugs and alcohol give short-term 'high' and long-term 'damages'.Discuss.

  • 5)

    For an organ transplant, it is advantageous to have an identical twin.why?

CBSE 12th Standard Biology Subject Human Health and Disease Ncert Exemplar 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Which protein occurs in the stratum corneum of epidermis?

  • 2)

    What would happen to immune system, if thymus gland is removed from the body of a person?

  • 3)

    Certain pathogens are tissue/organ specific.Justify the statement with suitable example.

  • 4)

    Name the toxin responsible for the appearance of symptoms of malaria in human. Why do these symptoms occurs periodically?

  • 5)

    The immune system of a person is suppressed. In the ELISA test, he was found positive to a pathogen.
    (i) Name the disease the patient is suffering from.
    (ii) What is the causative organism?
    (iii) Which cells of body are affected by the pathogen?

CBSE 12th Standard Biology Subject Human Health and Disease Ncert Exemplar 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Which protein occurs in the stratum corneum of epidermis?

  • 2)

    What would happen to immune system, if thymus gland is removed from the body of a person?

  • 3)

    Certain pathogens are tissue/organ specific.Justify the statement with suitable example.

  • 4)

    Name the toxin responsible for the appearance of symptoms of malaria in human. Why do these symptoms occurs periodically?

  • 5)

    Indiscriminate diagnostic practices using X - rays, etc., should be avoided. Give one reason.

CBSE 12th Standard Biology Subject Evolution Ncert Exemplar 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Name the law that states that the sum of allelic frequencies in a population remains constant. What are the five factors that influence these values?

  • 2)

    Explain divergent evolution in detail. What is driving force behind it?

  • 3)

    You have studied the story of Pepper moths in England. Had the industries been removed, what impact would it have on the moth population? Discuss.

  • 4)

    Two organisms occupying particular geographical area show similar adaptive strategies. Taking examples, describe the phenomenon.

  • 5)

    We are told that evolution is a continuing phenomenon for all living things. Are humans also evolving? Justify your answer.

CBSE 12th Standard Biology Subject Evolution Ncert Exemplar 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Explain divergent evolution in detail. What is driving force behind it?

  • 2)

    You have studied the story of Pepper moths in England. Had the industries been removed, what impact would it have on the moth population? Discuss.

  • 3)

    Two organisms occupying particular geographical area show similar adaptive strategies. Taking examples, describe the phenomenon.

  • 4)

    We are told that evolution is a continuing phenomenon for all living things. Are humans also evolving? Justify your answer.

  • 5)

    Had Darwin been aware of Mendel's work would have been able to explain the origin of variations. Discuss.

CBSE 12th Standard Biology Subject Evolution Ncert Exemplar 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    The evolutionary story of moths in England during industrialization reveals, that "evolution is apparently reversible". Clarify this statement.

  • 2)

    Comment on the statement that "evolution and natural selection are end result of consequences of some other processes but themselves are not processes.

  • 3)

    State and explain any three factors affecting allele frequency in populations.

  • 4)

    Gene flow occurs through generations. Gene flow can occur across language barriers in humans. If we have a technique of measuring specific allele frequencies in different population of the world, can we not predict human migratory patterns in pre-history and history? Do you agree or disagree? Provide explanation to your answer.

  • 5)

    How do you express the meaning of worlds like race, breed cultivars or variety?

CBSE 12th Standard Biology Subject Evolution Ncert Exemplar 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    The evolutionary story of moths in England during industrialization reveals, that "evolution is apparently reversible". Clarify this statement.

  • 2)

    Comment on the statement that "evolution and natural selection are end result of consequences of some other processes but themselves are not processes.

  • 3)

    State and explain any three factors affecting allele frequency in populations.

  • 4)

    Gene flow occurs through generations. Gene flow can occur across language barriers in humans. If we have a technique of measuring specific allele frequencies in different population of the world, can we not predict human migratory patterns in pre-history and history? Do you agree or disagree? Provide explanation to your answer.

  • 5)

    How do you express the meaning of worlds like race, breed cultivars or variety?

CBSE 12th Standard Biology Subject Evolution Ncert Exemplar 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    When we say 'survival of the fittest', does it mean that:
    (a) those whose are fit only survive or 
    (b) those that survive are called fit? Comment.

  • 2)

    'Migration may enhance or blur the effects of selection. Comment.

  • 3)

    Why is nascent oxygen supposed to be toxic to aerobic forms?

  • 4)

    What are we referring to when we say 'simple organisms' or 'complex organisms'?

  • 5)

    Rearrange the following in increasing order of evolution:Gnetales;Ferns;Zosterophyllum;Ginkgo.

CBSE 12th Standard Biology Subject Evolution Ncert Exemplar 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    When we say 'survival of the fittest', does it mean that:
    (a) those whose are fit only survive or 
    (b) those that survive are called fit? Comment.

  • 2)

    'Migration may enhance or blur the effects of selection. Comment.

  • 3)

    Why is nascent oxygen supposed to be toxic to aerobic forms?

  • 4)

    What are we referring to when we say 'simple organisms' or 'complex organisms'?

  • 5)

    Rearrange the following in increasing order of evolution:Gnetales;Ferns;Zosterophyllum;Ginkgo.

CBSE 12th Standard Biology Subject Evolution Ncert Exemplar 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    By what Latin name, is the first human-like being, the hominid known?

  • 2)

    Who probably did not eat meat among Ramapithecus, Australopithecus and Homo habilis?

  • 3)

    What are the characteristics of life forms that had been fossilised?

  • 4)

    Did aquatic life forms got fossilized? If yes, where do we come across such fossils?

  • 5)

    When we talk of functional macro-molecules e.g. protein as enzyme, hormones, receptor, antibodies, ect., towards what are they evolving?

CBSE 12th Standard Biology Subject Evolution Ncert Exemplar 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    How do we compute the age of a fossil?

  • 2)

    Did aquatic life forms got fossilized? If yes, where do we come across such fossils?

  • 3)

    How do we compute the age of a living tree?

  • 4)

    Give an example for convergent evolution and identify the features towards which they are converging.

  • 5)

    What is more important precondition for adaptive radiation?

CBSE 12th Standard Biology Subject Evolution Ncert Exemplar MCQ Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Presence of gills in the tadpole of frog indicates that

  • 2)

    Fossils are generally found in:

  • 3)

    The most accepted line of descent in human evolution is:

  • 4)

    Which of the following is an example for link species?

  • 5)

    Match the scientists listed under column 'A' with ideas listed in column 'B'.

     Column 1   Column 2 
    (i)   Darwin (M) abiogenesis 
    (ii)  Oparin (N) use and disuse of organs 
    (iii) Lamarck  (O) continental drift theory
    (iv) Wagner (P) evolution by natural selection

CBSE 12th Standard Biology Subject Evolution Ncert Exemplar MCQ Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    For the MN-blood group system, the frequencies of M and N alleles are 0.7 and 0.3, respectively. The expected frequency of MN-blood group bearing organisms is likely to be

  • 2)

    Which type of selection is industrial melanism observed in moth, Biston bitularia:

  • 3)

    The most accepted line of descent in human evolution is:

  • 4)

    Which of the following is an example for link species?

  • 5)

    Match the scientists listed under column 'A' with ideas listed in column 'B'.

     Column 1   Column 2 
    (i)   Darwin (M) abiogenesis 
    (ii)  Oparin (N) use and disuse of organs 
    (iii) Lamarck  (O) continental drift theory
    (iv) Wagner (P) evolution by natural selection

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance Ncert Exemplar 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Differentiate between the following
    (a) Repetitive DNA and Satellite DNA
    (b) mRNA and tRNA
    (c) Template strand and Coding strand

  • 2)

    (i)  Explain the process of DNA replication with the help of a schematic diagram.
    (ii) In which phase of the cell cycle does replication occur in eukaryotes? What would happen if cell division is not followed after DNA replication?

  • 3)

    The biology teacher asked her students to verify the experiment on transformation principle in bacteria to establish DNA as genetic material.The class was divided into groups.The teacher asked them to submit the reports.Group 2 did not use mouse and did not repeat GRiffith's experiment.The teacher praised them.
    (i) Which experiment did they perform?
    (ii) Explain the experiment in brief.
    (iii) Who and when performed the transformation principle experiment?
    (iv) What values did students of group 2 exhibit?

  • 4)

    Raj was a known sportsman in his school.While returning home he found unknown miscreants beating a young fellow.He tried to drive them off but by that time the fellow died of injury.The police arrested Raj and he was put on trial.The judge being convinced by Raj's plea, ordered for DNA fingerprinting reports.
    (i) What is the basis of DNA fingerprinting?
    (ii) Explain the steps in DNA fingerprinting.
    (iii) Write the applications of DNA fingerprinting.
    (iv) Raj's fingerprints on the dead body were sufficient to convict him but the judge asked for authentic proof.What values can observed by the judge?

  • 5)

    An organism is able to survive on a culture medium, containing nutrient A, by the enzyme-catalysed reactions.
    \(A\quad \underrightarrow { p } \quad B\quad \underrightarrow { q } \quad C\quad \underrightarrow { r } \quad D\)
    A mutant organism failed to survive on this medium, but grew well when nutrient  B was added to it.
    (i) Which gene of this mutant organism is defective?
    (ii) What does such a condition indicate of?
    (iii) Mention the major components and their functions in an operon.
    (iv) Indicate the value expressed in this sequence of reactions. 

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance Ncert Exemplar 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    (i) Describe the various steps of Griffith's experiment that led to the conclusion of the 'transforming principle'.
    (ii) How did the chemical nature of the 'transforming principle'get established?

  • 2)

    Study the schematic representation of the genes involved in the lac operon given below and answer the question that follows.

    p     i       po     z       y a

    i) Identify and name the regulatory gene in this operon .Explain its role in 'switching off' the operon.
    (ii) Why is lac operon's regulation referred to as negative regulation?
    (iii) Names the inducer molecule and the products of the genes 'z' and 'y' of the operon.Write the function of these gene products
    (iii) Names the inducer molecule and the products of the genes 'z' and 'y' of the operon.Write the function of these gene products.

  • 3)

    Differentiate between the following
    (a) Repetitive DNA and Satellite DNA
    (b) mRNA and tRNA
    (c) Template strand and Coding strand

  • 4)

    (i)  Explain the process of DNA replication with the help of a schematic diagram.
    (ii) In which phase of the cell cycle does replication occur in eukaryotes? What would happen if cell division is not followed after DNA replication?

  • 5)

    Raj was a known sportsman in his school.While returning home he found unknown miscreants beating a young fellow.He tried to drive them off but by that time the fellow died of injury.The police arrested Raj and he was put on trial.The judge being convinced by Raj's plea, ordered for DNA fingerprinting reports.
    (i) What is the basis of DNA fingerprinting?
    (ii) Explain the steps in DNA fingerprinting.
    (iii) Write the applications of DNA fingerprinting.
    (iv) Raj's fingerprints on the dead body were sufficient to convict him but the judge asked for authentic proof.What values can observed by the judge?

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance Ncert Exemplar 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Recall the experiment done by frederick Griffith, Avery, MacLeod and McCarty, where DNA was speculated to be the genatic material. If RNA, Instead of DNA was the genetic material, would the heat killed strain of Pneumococcus have tranformed the R-strain into virulent strain? Explain

  • 2)

    You are repeating the hershey-chase experiment and are provided with two isotope  \( 32_{ P }\) and \({ 15 }_{ N }\) (in place of \(35_{ S }\)  in the original experiment). How does yoou expect your results to be different

  • 3)

    How has the sequencing of human genome opened new windows for the treatment of various genetic disorders? Discuss amongst your classmates.

  • 4)

    The total number of genes in humans is far less (<25000) than the previous estimate (up to 140000 genes).Comment

  • 5)

    Describe transformation.

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance Ncert Exemplar 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 25, 2021 - View & Read

  • 1)

    Discuss the significance of heavy isotope of nitrogen.in Melson and Stahl's experiment.

  • 2)

    During DNA replication, why is it that the entire molecule does not open in one go? Explain replication fork. what is the two function that the monomers (dNTPs) play?

  • 3)

    Comments on the utility of variability in a number of tendons repeat during DNA fingerprinting.

  • 4)

    Compare the primary structure of nucleic acid and protein

  • 5)

    Why was it believed earlier that proteins could be genetic material?

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance Ncert Exemplar 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Recall the experiment of Frederick Griffith.If RNA instead of DNA was the genetic material would the heat-killed S-strain of the bacteria have transformed the R-strain into S-strain? Explain your answer

  • 2)

    What is the cause of discontinuous synthesis of DNA on one of the parental strands of DNA?What happens to these short stretches of the DNA synthesised?

  • 3)

    What are the functions of
    (i) methylated guanosine cap and
    (ii) poly A-tail in a mature mRNA?

  • 4)

    There in only one possible sequence of amino acids when deduced from a given set of nucleotides.But multiple nucleotide sequences can be deduced from a single amino acid sequence .Explain this phenomenon.

  • 5)

    A single base mutation in a gene may not 'always' result in loss or gain of function.Do you think the statement is correct?Define your answer.

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance Ncert Exemplar 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Recall the experiment of Frederick Griffith.If RNA instead of DNA was the genetic material would the heat-killed S-strain of the bacteria have transformed the R-strain into S-strain? Explain your answer

  • 2)

    What is the cause of discontinuous synthesis of DNA on one of the parental strands of DNA?What happens to these short stretches of the DNA synthesised?

  • 3)

    What are the functions of
    (i) methylated guanosine cap and
    (ii) poly A-tail in a mature mRNA?

  • 4)

    Explain when is a genetic code said to be
    (i) Degenerate (ii) Universal

  • 5)

    Name a few enzymes involved in DNA replication other than DNA polymerase and ligase. Name the key function for each of them.

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance Ncert Exemplar 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    What will be the ratio of  15N/15N :15N/14N : 14N/14N containing DNAs,if Meselson and Stahl experiment is cotinued for four generations in the bacteria?

  • 2)

    What is the function of histones in DNA packaging?

  • 3)

    The enzyme DNA polymerase on E.coli is a DNA-dependent polymerase and also has the ability to proof-read the DNA strand being synthesised. Explain. Discuss the dual polymerase.

  • 4)

    Given below is the sequences of the coding strand of DNA in a transcription unit 3' AATGCAGCTATTAGG -5'. write the sequence of:
    a) It's complementary strand
    b)The mRNA.

  • 5)

    Based on your understanding of genetic code, explain the formation of any abnormal haemoglobin molecule. what are the known consequence of such a change?

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance Ncert Exemplar 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    In an experiment DNA is treated with a compound which tends to place itself amongst the stacks of nitrogenous base pairs. As a result of this the distance between two consecutive base pairs increases from 0.34nm to 0.44 nm. Calculate the length of DNA double helix, which has 2 x 109bp in the presence of saturating amount of this compound.

  • 2)

    What would happen if histones were to be mutated and made rich in amino acids and glutamic acid in place of basic amino acids such as lysine and arginine?

  • 3)

    In some viruses DNA is synthesised using RNA template. What term is given to such a DNA?

  • 4)

    What will be the ratio of  15N/15N :15N/14N : 14N/14N containing DNAs,if Meselson and Stahl experiment is cotinued for four generations in the bacteria?

  • 5)

    The enzyme DNA polymerase on E.coli is a DNA-dependent polymerase and also has the ability to proof-read the DNA strand being synthesised. Explain. Discuss the dual polymerase.

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance Ncert Exemplar MCQ Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    The human chromosomes with the highest and least number of genes in them are respectively:

  • 2)

    Who amongst the following scientists had no contribution in the development of the double helix model for the structure of DNA?

  • 3)

    DNA is a polymer of nucleotides which are linked to each other by 3'-5' phosphodiester bond. To prevent polymerisation of nucleotides, which of the following modifications would you choose?

  • 4)

    Regulatory proteins are the accessory proteins that interact with RNA polymerase and affect its role in transcription. Which of the following statements is correct about regulatory protein?

  • 5)

    Which was the last human chromosome to be completely sequenced:

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance Ncert Exemplar MCQ Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    The distance between the genes a,b,c,d in mapping units are
    a-d=3.5; b-c=1; a-b=6; 
    c-d=1.5; a-c=5
    Find out the sequence of arrangement of these genes

  • 2)

    The human chromosomes with the highest and least number of genes in them are respectively:

  • 3)

    Who amongst the following scientists had no contribution in the development of the double helix model for the structure of DNA?

  • 4)

    DNA is a polymer of nucleotides which are linked to each other by 3'-5' phosphodiester bond. To prevent polymerisation of nucleotides, which of the following modifications would you choose?

  • 5)

    Control of gene expression takes place at the level of:

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation Ncert Exemplar 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    With help of an example, differentiate between incomplete dominance and codominance.

  • 2)

    How was it conclused that genes are located on chromosome?

  • 3)

    Fill in the Blanks:
    (i)The________ shown by the individuals of species and also by the________of the same parents are referred to as variation.
    (ii)Germinal variations affect the________cells of the organism and are, consequently, inheritable. on the other hand, somatic variations affects the________cells of an organism and are not inheritable.
    (iii)Theory of pangenesis was forwarded by.... He assumed that tiny representative partice called________by him are formed in each part of body and migrated via blood to the games and thences to the offsprings to guide the formation of the respective part.
    (iv)Mendel's results were rediscovered in 1900 independently by three biologists namely________ and ________.
    (v)Mendel worked on________ and gave famous laws of inheritance
    (Vi)The phenotypic ratio obtained by mendel in his famous monohybrid cross in F2 generation was________while the genotypic ratio was________

  • 4)

    Identify the phenomenon in the following example-
    "Sickle cell anaemia is an autosomal recessive trait.It is caused by the substitution of anino acid glutamic acid by valine at the sixth position of the beta globin chain of haemoglobin.This substitution of amino acid occurs due to phenomenon in which the sixth codon of beta globin gene is transformed from GAG to GUG".

  • 5)

    Flowers of garden pea are biseual and self pollinated.therefore,it is difficult to perform hybrindization experiment by crossing a particular pistil with the specific pollen grains.Hoew mendel made it possible in his monohybrid, dihybrid and trihybrid crosses?

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation Ncert Exemplar 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    How was it conclused that genes are located on chromosome?

  • 2)

    Fill in the Blanks:
    (i)The________ shown by the individuals of species and also by the________of the same parents are referred to as variation.
    (ii)Germinal variations affect the________cells of the organism and are, consequently, inheritable. on the other hand, somatic variations affects the________cells of an organism and are not inheritable.
    (iii)Theory of pangenesis was forwarded by.... He assumed that tiny representative partice called________by him are formed in each part of body and migrated via blood to the games and thences to the offsprings to guide the formation of the respective part.
    (iv)Mendel's results were rediscovered in 1900 independently by three biologists namely________ and ________.
    (v)Mendel worked on________ and gave famous laws of inheritance
    (Vi)The phenotypic ratio obtained by mendel in his famous monohybrid cross in F2 generation was________while the genotypic ratio was________

  • 3)

    Identify the phenomenon in the following example-
    "Sickle cell anaemia is an autosomal recessive trait.It is caused by the substitution of anino acid glutamic acid by valine at the sixth position of the beta globin chain of haemoglobin.This substitution of amino acid occurs due to phenomenon in which the sixth codon of beta globin gene is transformed from GAG to GUG".

  • 4)

    Identify the type of inheritance shown in the following pedigree diagram.

  • 5)

    During a monohybrid cross involving a tall pea plant with a dwarf pea plant, the offspring populations were tall and dwarf in equal ratio.Workout a cross to show how it is possible.

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation Ncert Exemplar 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    If a father and son are both defective in red-green colour vision, is it likely that the son inherited the trait from his father?  Comment.

  • 2)

    In our society, a woman is often blamed for not bearing a male child.Do you think it is right? Justify

  • 3)

    The pedigree chart given below shows a particular trait which is absent in parents but present in the next generation irrespective of sexes.
    Draw your conclusion on the basis of the pedigree.

  • 4)

    How is the child affected, if it has grown from the zygote formed by an XX-egg fertilised by a Y-carrying sperm? What do you call this abnormality?

  • 5)

    A woman of 47 years delivered an abnormal child with a flattened nasal bridge and mouth partially open with a large protruding tongue. Name this genetic abnormality. What causes this condition?

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation Ncert Exemplar 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    If a father and son are both defective in red-green colour vision, is it likely that the son inherited the trait from his father?  Comment.

  • 2)

    In our society, a woman is often blamed for not bearing a male child.Do you think it is right? Justify

  • 3)

    The pedigree chart given below shows a particular trait which is absent in parents but present in the next generation irrespective of sexes.
    Draw your conclusion on the basis of the pedigree.

  • 4)

    Linkage and crossing over of genes are alternatives of each other. Justify with the help of an example.

  • 5)

    A woman of 47 years delivered an abnormal child with a flattened nasal bridge and mouth partially open with a large protruding tongue. Name this genetic abnormality. What causes this condition?

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation Ncert Exemplar 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    What are the characteristic features of a true-breeding line?

  • 2)

    In order to obtain the F1 generation, Mendel pollinated a pure-breeding tall plant with a pure-breeding dwarf plant.  But, for getting the F2 generation, he simply self-pollinated the tall F1 plants.  Why?

  • 3)

    What is the cross between the progeny of F1 and the homozygous recessive parent called? How is it useful?

  • 4)

    Even if a character shows multiple allelism an individual will only have two allels for that character.  Why?

  • 5)

    Do you think Mendel's law of inheritance would have been different if the characters he chose were located on the same chromosome? Why?

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation Ncert Exemplar 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    What are the characteristic features of a true-breeding line?

  • 2)

    In order to obtain the F1 generation, Mendel pollinated a pure-breeding tall plant with a pure-breeding dwarf plant.  But, for getting the F2 generation, he simply self-pollinated the tall F1 plants.  Why?

  • 3)

    What is the genetic basis of wrinkled phenotype of pea seed?

  • 4)

    What is the cross between the progeny of F1 and the homozygous recessive parent called? How is it useful?

  • 5)

    Do you think Mendel's law of inheritance would have been different if the characters he chose were located on the same chromosome? Why?

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation Ncert Exemplar MCQ Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Mendel's Law of independent assortment holds good for genes situated on the :

  • 2)

    In a certain taxon of insects some have 17 chromosomes and the others have 18 chromosomes. The 17 and 18 chromosome-bearing organisms are :

  • 3)

    The inheritance pattern of a gene over generations among humans is studied by the pedigree analysis. Character studied in the pedigree analysis is equivalent to :

  • 4)

    It is said that Mendel proposed that the factor controlling any character is discrete and independent. This proposition was based on the :

  • 5)

    In the F2 generation of a Mendelian dihybrid cross the number of phenotypes and genotypes are :

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation Ncert Exemplar MCQ Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Occasionally, a single gene may express more than one effect. The phenomenon is called :

  • 2)

    In a certain taxon of insects some have 17 chromosomes and the others have 18 chromosomes. The 17 and 18 chromosome-bearing organisms are :

  • 3)

    The inheritance pattern of a gene over generations among humans is studied by the pedigree analysis. Character studied in the pedigree analysis is equivalent to :

  • 4)

    It is said that Mendel proposed that the factor controlling any character is discrete and independent. This proposition was based on the :

  • 5)

    In the F2 generation of a Mendelian dihybrid cross the number of phenotypes and genotypes are :

CBSE 12th Standard Biology Subject Reproductive Health Ncert Exemplar 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Enumerate and describe any five reasons for sex education to school-going children.

  • 2)

    Your school has been selected by the Department of Education to organize and host an interschool seminar on 'Reproductive Health problems and Practices', However, many parents are reluctant to permit their wards to attend it. Their argument is that the topic is 'too embar raddling'. Put forth four arguments with appropriate reasons and explanations to justify the topic to be very essential and timely.

  • 3)

    On world population day, Rohit and his friends arranged an awareness campaign on population explosion programme in their locality. Some elderly people tried to stop the children and asked them not to talk about such things in public.
    The children convinced the elders about the need for the programme and on understanding their point of view, the elders also joined the campaign.
    (i) Why is such awareness programme necessary?
    (ii) What role has the government played in controlling population explosion?
    (iii) When were reproductive health programmes initiated in India?
    (iv) What values did Rohit and his friends show on the occasion?

  • 4)

    Some parents wrote a complaint letter to the local municipality to remove all the hoardings in the city, advertising the use of condoms and matters relating to AIDS prevention. The children of these parents came to know about the matter and raised their voice against the removal of the hoardings. The parents were convinced by the awareness level of their children and withdrew the complaint.
    (i) Parents considered the hoarding as inappropriate. Do you agree/disagree with their view?
    (ii) What are the methods by which AIDS spreads?
    (iii) What is AIDS?
    (iv) What values are promoted by the children protesting against their parents?

  • 5)

    During a visit to Vaishno Devi, Rahul came across a young couple staying in the adjacent room in the hotel.
    He learned that the couple had been visiting different temples and performing rituals to get a child. Rahul was astonished and explained to them about ART which he had recently studied in biology. The couple were happy and understood their wrong approach and thanked Rahul.
    (i) What is ART? What is the various method included in ART?
    (ii) What are the limitations for which ART is not commonly accepted?
    (iii) Identify the values which Rahul showed.

CBSE 12th Standard Biology Subject Reproductive Health Ncert Exemplar 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Do you justify the statutory ban on amniocentesis in our country? Give reasons.

  • 2)

    Enumerate and describe any five reasons for sex education to school-going children.

  • 3)

    Your school has been selected by the Department of Education to organize and host an interschool seminar on 'Reproductive Health problems and Practices', However, many parents are reluctant to permit their wards to attend it. Their argument is that the topic is 'too embar raddling'. Put forth four arguments with appropriate reasons and explanations to justify the topic to be very essential and timely.

  • 4)

    On world population day, Rohit and his friends arranged an awareness campaign on population explosion programme in their locality. Some elderly people tried to stop the children and asked them not to talk about such things in public.
    The children convinced the elders about the need for the programme and on understanding their point of view, the elders also joined the campaign.
    (i) Why is such awareness programme necessary?
    (ii) What role has the government played in controlling population explosion?
    (iii) When were reproductive health programmes initiated in India?
    (iv) What values did Rohit and his friends show on the occasion?

  • 5)

    Mrs. Sharma was eager to know the sex of the foetus, which her daughter-in-law was carrying. She was so anxious that she could pay any amount for that. The doctor refused to disclose the result of the test.
    (i) How can one know the sex of the foetus?
    (ii) How is it done?
    (iii) Why is disclosing the sex of the foetus banned in our country?
    (iv) What value do you learn from the doctor's act?

CBSE 12th Standard Biology Subject Reproductive Health Ncert Exemplar 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    A couple where both husband and wife are producing functional gametes, but the wife is still unable to conceive, is seeking medical aid.
    Describe any one method that you can suggest to this couple to become happy parents.

  • 2)

    Women are often blamed for producing female children. Consequently, they are ill-treated and ostracized. How will you address this issue scientifically if you were to conduct an awareness programme to highlight the values involved?

  • 3)

    'Introducing sex education in schools is a good step for providing the right information to adolescents'. In context to the statement given above, answer the questions that follow:
    (i) Which part of the brain controls the sex urge?
    (ii) what are the necessary topics that should be taught in schools, in the context of STDs and AIDS?
    (iii) What do you understand by the term emotional brain?

  • 4)

    The hormonal methods of contraception are widely used and are known to cause changes either in the ovulation pattern or in the female reproductive tract. Explain the hormonal control of a female reproductive system (with the help of flow chart only) which helps in understanding the mechanism of action of these methods.

  • 5)

    With reference to a natural method of family planning, called lactational amenorrhea, answer the questions that follow:
    (i) Is this a permanent method to avoid pregnancy?
    (ii) Can Lactational amenorrhea be seen among oviparous organisms?
    (iii) with respect to human health, what do you understand by the term the 'sterilization'?

CBSE 12th Standard Biology Subject Reproductive Health Ncert Exemplar 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    A couple where both husband and wife are producing functional gametes, but the wife is still unable to conceive, is seeking medical aid.
    Describe any one method that you can suggest to this couple to become happy parents.

  • 2)

    Women are often blamed for producing female children. Consequently, they are ill-treated and ostracized. How will you address this issue scientifically if you were to conduct an awareness programme to highlight the values involved?

  • 3)

    'Introducing sex education in schools is a good step for providing the right information to adolescents'. In context to the statement given above, answer the questions that follow:
    (i) Which part of the brain controls the sex urge?
    (ii) what are the necessary topics that should be taught in schools, in the context of STDs and AIDS?
    (iii) What do you understand by the term emotional brain?

  • 4)

    The hormonal methods of contraception are widely used and are known to cause changes either in the ovulation pattern or in the female reproductive tract. Explain the hormonal control of a female reproductive system (with the help of flow chart only) which helps in understanding the mechanism of action of these methods.

  • 5)

    With reference to a natural method of family planning, called lactational amenorrhea, answer the questions that follow:
    (i) Is this a permanent method to avoid pregnancy?
    (ii) Can Lactational amenorrhea be seen among oviparous organisms?
    (iii) with respect to human health, what do you understand by the term the 'sterilization'?

CBSE 12th Standard Biology Subject Reproductive Health Ncert Exemplar 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Suggest the reproduction-related aspects in which counseling should be provided at the school level.

  • 2)

    Copper ions-releasing IUDs are more efficient than non-medicated methods. Why?

  • 3)

    What are the probable factors that contributed to population explosion in India?

  • 4)

    Briefly, explain the IVF and ET. What are the conditions in which these methods are advised?

  • 5)

    What are the conditions in which medical termination of pregnancy is advised?

CBSE 12th Standard Biology Subject Reproductive Health Ncert Exemplar 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Suggest the reproduction-related aspects in which counseling should be provided at the school level.

  • 2)

    What are the probable factors that contributed to population explosion in India?

  • 3)

    Briefly, explain the IVF and ET. What are the conditions in which these methods are advised?

  • 4)

    What are advantages of natural methods of contraception over artificial methods?

  • 5)

    All reproductive tract infections RTIs, are STDs, but all STDs are not RTIs. Justify with example.

CBSE 12th Standard Biology Subject Reproductive Health Ncert Exemplar 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Reproductive health refers only to healthy reproductive functions.Comment.

  • 2)

    The present population growth rate in India is alarming.Suggest ways check it.

  • 3)

    STDs can be considered as self-invited diseases.Comment.

  • 4)

    Strict conditions are to be followed in Medical Termination of Pregnancy (MTP) procedures.mention two reasons.

  • 5)

    Mention the primary aim of the 'Assisted Reproductive Technology' (ART) programme.

CBSE 12th Standard Biology Subject Reproductive Health Ncert Exemplar 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Reproductive health refers only to healthy reproductive functions.Comment.

  • 2)

    The present population growth rate in India is alarming.Suggest ways check it.

  • 3)

    STDs can be considered as self-invited diseases.Comment.

  • 4)

    Strict conditions are to be followed in Medical Termination of Pregnancy (MTP) procedures.mention two reasons.

  • 5)

    Mention the primary aim of the 'Assisted Reproductive Technology' (ART) programme.

CBSE 12th Standard Biology Subject Reproductive Health Ncert Exemplar MCQ Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Choose the correct answer regarding the ZIFT procedure?

  • 2)

    The correct surgical procedure as a contraceptive method is:

  • 3)

    Condoms are one ofthe most popular contraceptives because of the following reasons

  • 4)

    Intensely lactating mothers do not generally conceive due to the

  • 5)

    The method of directly injecting a sperm into ovum in assisted reproductive, technology is called

CBSE 12th Standard Biology Subject Reproductive Health Ncert Exemplar MCQ Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Given below are the four methods and their modes of action in achieving contraception.Select their correct matching from the four options that follows.

    control measures

    		 Mode of Action
    (A) Pill 1.  Prevents sperms reaching cervix
    (B) Condom 2. Prevents implication
    (C)Vasectomy 3. Prevents ovulation 
    (D) Copper T 4. Semen contains no sperms

     

  • 2)

    Amniocentesis is a process to

  • 3)

    Choose the correct answer regarding the ZIFT procedure?

  • 4)

    The correct surgical procedure as a contraceptive method is:

  • 5)

    Diaphragms are contraceptive devices used by the females. Choose the correct option from the statements given below:
    (i)  They are introduced into the uterus
    (ii)  They are placed to cover the cervical region
    (iii) They act as physical barriers for sperm entry
    (iv)  They act as spermicidal agents

CBSE 12th Standard Biology Subject Human Reproduction Ncert Exemplar 5 Mark Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    What roles does pituitary gonadotrophins play during follicular and ovulatory phases of menstrual cycle? Explain the shifts in steroidal secretions. 

  • 2)

    The zygote passes through several development stages till implantation.Describe each stage briefly with suitable diagrams.

  • 3)

    Describe the specific action of FSH, LH, oestrogen and progesterone in the menstrual cycle.

  • 4)

    Study the graph given below and answer the questions that follow.

    (i) Name the hormones 'X' and 'Y'.
    (ii) Identify the ovarian phases during menstrual cycle.
    (a) 5th-12th day of the cycle.
    (b) 14th day of the cycle.
    (c) 16th-25th day of the cycle.
    (iii) Explain the ovarian events (a), (b) and (c) under the influence of hormones 'X' and 'Y'

  • 5)

    With reference for events starting from menstrued cycle till the events of parturition give the name of the hormones involved at each stage and explain their role.

CBSE 12th Standard Biology Subject Human Reproduction Ncert Exemplar 5 Mark Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    What roles does pituitary gonadotrophins play during follicular and ovulatory phases of menstrual cycle? Explain the shifts in steroidal secretions. 

  • 2)

    The zygote passes through several development stages till implantation.Describe each stage briefly with suitable diagrams.

  • 3)

    With reference for events starting from menstrued cycle till the events of parturition give the name of the hormones involved at each stage and explain their role.

  • 4)

    During the biology class, teacher was explaining the human reproductive system. Ankita was busy doing work of some other subject and so missed on the topic. When the teacher asked questions Ankita was unable to answer them. She, however, realised her mistake and requested the teacher to explain the topic once again. The teacher happily repeated.
    (i) What is the primary sex organ in male?
    (ii) What is tunica albuginea?
    (iii) Name the three layers of tissue of uterus.
    (iv) Identify the values shown by the teacher.

  • 5)

    Vaibhav, 12th class student watched the movie 'Vickey donar'. He was very curious to know the structure and details of sperm. He wondered, why the donation of sperm is considered a taboo irrespective of the fact that it helps childless couples to have children. He discussed this whole thing with his elder brother, who is a biology professor in a university. His brother smiled and explained all his queries.
    (i) Name the main parts of a sperm.
    (ii) Which part of the human sperm is responsible for facilitating sperm motility? Explain.
    (iii) What are the values shown by Vaibhav?

CBSE 12th Standard Biology Subject Human Reproduction Ncert Exemplar 3 Mark Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Meiotic division during oogenesis is different from that in spermatogenesis. Explain how and why?

  • 2)

    Study the given figure carefully and answer the following question:
    (i) Label the parts marked as (a), (b), (c), (d) and (e).
    (ii) Give one major function of each part.

  • 3)

    Fill in the blanks:
    (i) Primary sex organ are called______.and secondary sex organ include______. and reproductive glands.
    (ii) Seminiferous tubules produce______.while interstitial (Leydig's) cells produce ______.
    (iii) Vas efferentia carry spermatozoa from ______. to______.
    (iv) Vasa deferentia carry spermatozoa from______. to ______.
    (v) In females, urethra is small and conducts ______.while in males it conducts urine and ______.
    (vi) Penis is an external intromittent organ which contains 3 columns of spongy tissue: two column of ______. on the front side and one column of ______. around the urethra.
    (vii) The process of formation of spermatozoa from spermatogonia is called ______. and the process of maturation of spermatids into spermatozoa is called______.

  • 4)

    Mark the wrong items in each series...
    (i) Scrotum rete testis, fallopian tube, vas deferens.
    (ii) Ovary, uterus, vagina, ejaculatory duct.
    (iii) Acrosome, Graafian follicle, corpus luteum, cervix.
    (iv) Fission, budding, fragmentation, Gametogenesis.
    (v) Prostate, testis, seminal vesicles, Cowper's gland.

  • 5)

    When and where does spermatogenesis occur in a human male?

CBSE 12th Standard Biology Subject Human Reproduction Ncert Exemplar 3 Mark Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Study the given figure carefully and answer the following question:
    (i) Label the parts marked as (a), (b), (c), (d) and (e).
    (ii) Give one major function of each part.

  • 2)

    Fill in the blanks:
    (i) Primary sex organ are called______.and secondary sex organ include______. and reproductive glands.
    (ii) Seminiferous tubules produce______.while interstitial (Leydig's) cells produce ______.
    (iii) Vas efferentia carry spermatozoa from ______. to______.
    (iv) Vasa deferentia carry spermatozoa from______. to ______.
    (v) In females, urethra is small and conducts ______.while in males it conducts urine and ______.
    (vi) Penis is an external intromittent organ which contains 3 columns of spongy tissue: two column of ______. on the front side and one column of ______. around the urethra.
    (vii) The process of formation of spermatozoa from spermatogonia is called ______. and the process of maturation of spermatids into spermatozoa is called______.

  • 3)

    When and where does spermatogenesis occur in a human male?

  • 4)

    Differentiate between vasa efferentia and vasa deferentia.

  • 5)

    Identify A,B,C and D with reference to gametogenesis in humans in the flow chart given below.

CBSE 12th Standard Biology Subject Human Reproduction Ncert Exemplar 2 Mark Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Given below are the stages in human reproduction.Write them in the correct sequential order:
    Insemination, Gametogenesis, Fertilisation, Parturition, Gestation, Implantation.

  • 2)

    Corpus luteum is pregnancy has a long life.However, if fertilisation does not take place, it remains active only for 10-12 days.Explain.

  • 3)

    What is foetal ejection reflex? Explain how it leads to parturition?

  • 4)

    Except endocrine function, what are other functions of placenta?

  • 5)

    What are the changes in the oogonia during the transition of a primary follicle to Graafian follicle?

CBSE 12th Standard Biology Subject Human Reproduction Ncert Exemplar 2 Mark Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Given below are the stages in human reproduction.Write them in the correct sequential order:
    Insemination, Gametogenesis, Fertilisation, Parturition, Gestation, Implantation.

  • 2)

    Why are menstrual cycles absent during pregnancy?

  • 3)

    What is capacitation?

  • 4)

    Name two organisms which lack sexual reproduction and are immortal. What is an asexual reproductive unit called?

  • 5)

    Differentiate between spermatogenesis and spermiogenesis.

CBSE 12th Standard Biology Subject Human Reproduction Ncert Exemplar 1 Mark Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Which type of cell division forms spermatids from the secondary spermatocytes?

  • 2)

    During reproduction,the chromosome number (2n) reduces to half (n) in the gametes and again the original number (2n) is restored in the offspring.What are the process through which these events take place?

  • 3)

    What is the difference between a primary oocyte and a secondary oocyte ?

  • 4)

    Mention the importance of LH surde during menstrual cucle.

  • 5)

    What is the significance of ampullaryisthmic junction in the female reproductive tract?

CBSE 12th Standard Biology Subject Human Reproduction Ncert Exemplar 1 Mark Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Which type of cell division forms spermatids from the secondary spermatocytes?

  • 2)

    What is the difference between a primary oocyte and a secondary oocyte ?

  • 3)

    Mention the importance of LH surde during menstrual cucle.

  • 4)

    What is the significance of ampullaryisthmic junction in the female reproductive tract?

  • 5)

    Give the names and functions of the hormones involved in the process of spermatogenesis.Write the names of the endocrine glands from where they are released.

CBSE 12th Standard Biology Subject Human Reproduction Ncert Exemplar MCQ Questions With Solution2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    1st polar body is formed at which state of oogenesis?

  • 2)

    Which one of the following is the correct matching of the events occurring during menstrual cycle?

  • 3)

    Which one of the following is the most likely root cause why menstruation is not taking place in the regularly cycling human female?

  • 4)

    The correct sequence of spermatogenic stages leading to the formation of sperms in a mature human testis is

  • 5)

    Match the following and choose the correct options:

    A Trophoblast Embedding of blastocyst
    in the endometrium
    B Cleavage Group of cells that would
    differentiate as embryo
    C Inner cell mass Outer layer of blastocyst
    attached to the endometrium
    D Implantation Mitotic division of zygote

CBSE 12th Standard Biology Subject Human Reproduction Ncert Exemplar MCQ Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Which one of the following is the correct matching of the events occurring during menstrual cycle?

  • 2)

    Which one of the following is the most likely root cause why menstruation is not taking place in the regularly cycling human female?

  • 3)

    The correct sequence of spermatogenic stages leading to the formation of sperms in a mature human testis is

  • 4)

    Which among the following has 23 chromosomes?

  • 5)

    Match the following and choose the correct options:

    A Trophoblast Embedding of blastocyst
    in the endometrium
    B Cleavage Group of cells that would
    differentiate as embryo
    C Inner cell mass Outer layer of blastocyst
    attached to the endometrium
    D Implantation Mitotic division of zygote

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants Ncert Exemplar 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Observe the figure carefully and the answer of the following question:

    (a) Write whether ovary is superior or inferior?
    (b) What is the type of flower - hypogynous, perigynous or epigynous?
    (c) What type of ovule is shown the figure?
    (d) What changes occur in C after fertilization?
    (e) What does A, B, C, D represent in the figure.

  • 2)

    Do you think microspores and pollen grains are the same structures. If they are different then what is the basic difference between them?

  • 3)

    In the diagram given below, identify the parts of the flower and mention the post-fertilisation changes shown in the parts

  • 4)

    From the recent studies, it was found that one of the common fruit banana is one the verge of extinction, as a new fungal disease is plaguing banana plants.
    (i) State what could be the possible reasons against this condition
    (ii) Describe the phenomenon reasons against this condition
    (iii) Suggest a technique to overcome this forthcoming problem.

  • 5)

    Starting with the zygote, draw the diagrams of the different stages of embryo development in a dicot.

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants Ncert Exemplar 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    A _______ is the development of seeds from unfertilised female gamete.
    B. Parthenocarpy is the development  of______in an unfertilised flower, resulting in a_______
    C. Polyembryony is the presence of more than one_______ in the_______
    D. There are usually three germ pores in _______and one in _______
    E. The anther wall is composed of_______to_______layers. 
    F. The flowers producing _______ and _______ with bright _______ attract the insects.
    G. Plants with reduced power of _______ reproduction, _______ dormant period of seed or _______ viability are propagated through vegetative reproduction.
    H. The integuments of ovule surround the_______all around expect at the apex, leaving a narrow passage, called the _______.
    I. The wind-pollinated flowers are generally _______sexual.
    J. In many dicots, the reserves in the _______ and consumed by the developing embryo.

  • 2)

    Do you think microspores and pollen grains are the same structures. If they are different then what is the basic difference between them?

  • 3)

    In the diagram given below, identify the parts of the flower and mention the post-fertilisation changes shown in the parts

  • 4)

    Given below are the events that are observed in an artificial hybridisation programme. Selection of parents--->Emasculation--->Bagging--->Collection of pollen from other male plant--->Dusting of pollen on stigma ---->Re-bagging. While planning for crop improvement involving dioecious plants. Which of the above mentioned steps would not be relevant?

  • 5)

    Starting with the zygote, draw the diagrams of the different stages of embryo development in a dicot.

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants Ncert Exemplar 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    What are the functions of the two male gametes produced by each pollen grain in angiosperms?

  • 2)

    Are parthenocarpy and apomixis different phenomena? Discuss their benefits.

  • 3)

    Are pollination and fertilisation necessary in apomixis? Give reason.

  • 4)

    Which are three cells found in pollen grain when it is shed at the three called stage?

  • 5)

    What is the function of two male gametes produced by each pollen grain in angiosperms?

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants Ncert Exemplar 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    The probability of fruit set in a self-pollinated bisexual flower of a plant is far greater than a dioecious plant explain

  • 2)

    Name the type of pollination in self-incompatible plants.

  • 3)

    Are pollination and fertilisation necessary in apomixis? Give reason.

  • 4)

    What is seed dormancy ? Give any two advantages of seed dormancy.

  • 5)

    Indicate the stages where meiosis and mitosis occur (1, 2 or 3) in the flow chart
    Megspore mother cell \(\overset { 1 }{ \rightarrow } \) Megaspores \(\overset { 2 }{ \rightarrow } \) Embryo sac \(\overset { 3 }{ \rightarrow } \)Egg.

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants Ncert Exemplar 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Name the part of gynoecium that determines the compatible nature of pollen grain.

  • 2)

    What is nucellus?

  • 3)

    Why are pollen grains produced in enormous quantity in Maize?

  • 4)

    Give the name of the common function that cotyledons and nucellus perform

  • 5)

    What is the disadvantage of self-pollination?

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants Ncert Exemplar 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    What is nucellus?

  • 2)

    Why are pollen grains produced in enormous quantity in Maize?

  • 3)

    Give the name of the common function that cotyledons and nucellus perform

  • 4)

    What is the disadvantage of self-pollination?

  • 5)

    Can an unfertilised apomictic embryo sac give rise to a diploid embryo? If yes, then how?

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants Ncert Exemplar MCQ Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Select the correct order of endosperm types

  • 2)

    From among the sets of terms given below, identify those that are associated with gynoecium.

  • 3)

    The outermost and innermost wall layers of microsporangium in an anther are respectively

  • 4)

    From the statements given below choose the option that is true for a typical female gametophyte of a flowering plant:
    i) It is 8-nucleate and 7-celled at maturity
    ii) It is free nuclear during development
    iii) It is situated inside the integument but outside the nucellus
    iv) It has an egg apparatus situated at the chalazal end.

  • 5)

    In a flower, if a megaspore mother cell forms megaspores without undergoing meiosis and if one of the megaspores develops into an embryo sac, its nuclei would be

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants Ncert Exemplar MCQ Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Embryo sac is to ovule __________  is to an anther

  • 2)

    From among the sets of terms given below, identify those that are associated with gynoecium.

  • 3)

    The outermost and innermost wall layers of microsporangium in an anther are respectively

  • 4)

    From the statements given below choose the option that is true for a typical female gametophyte of a flowering plant:
    i) It is 8-nucleate and 7-celled at maturity
    ii) It is free nuclear during development
    iii) It is situated inside the integument but outside the nucellus
    iv) It has an egg apparatus situated at the chalazal end.

  • 5)

    While planning for an artificial hybridization programme involving dioecious plants, which of the following steps will be irrelevent:

CBSE 12th Standard Biology Subject Reproduction in Organisms Ncert Exemplar 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Enumerate the differences between asexual and sexual reproduction. Describe the types of asexual reproduction exhibited by unicellular organisms.

  • 2)

    Difference between:
    (a) Oestrous cycle and menstrual cycle
    (b) Ovipary and vivipary. City an example of each type .

  • 3)

    Differentiate between
    i) estrous and menstrual cycle
    ii) oviparity and vivipary.Give an example of each type.

  • 4)

    Do all the gametes formed from a parent organism have the same genetic composition (identical DNA copies of the parental genome)? Analyze the situation with the background of gametogenesis and provide or give a suitable explanation.

  • 5)

    Differentiate between
    (i) oestrus and menstrual cycle
    (ii) ovipary and vivipary. Give an example for each type.

CBSE 12th Standard Biology Subject Reproduction in Organisms Ncert Exemplar 5 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Enumerate the differences between asexual and sexual reproduction. Describe the types of asexual reproduction exhibited by unicellular organisms.

  • 2)

    Although sexual Reproduction is a long drawn, energy intensive complex from of reproduction, many groups of organisms in Kindom Animalia and Plantae prefer this mode of reproduction. Give atleast three reasons for this.

  • 3)

    Differentiate between
    i) estrous and menstrual cycle
    ii) oviparity and vivipary.Give an example of each type.

  • 4)

    Do all the gametes formed from a parent organism have the same genetic composition (identical DNA copies of the parental genome)? Analyze the situation with the background of gametogenesis and provide or give a suitable explanation.

  • 5)

    Differentiate between
    (i) oestrus and menstrual cycle
    (ii) ovipary and vivipary. Give an example for each type.

CBSE 12th Standard Biology Subject Reproduction in Organisms Ncert Exemplar 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    The diagram given below shows a plant charm. Refer to the diagram and answer the questions that follow. Which types of sexuality does this plant have?

    ii) Give an example of any other plant which has same sexuality
    ii) Fill in the blanks in the given statement.
    Flowers with stamen are called______ flowers.
    Flowers with pistil are called____ flowers.

  • 2)

    Refer to the diagram given below and answer the questions that follow.

    i) Label the parts A and B
    ii) Which part of flower develops into seed and fruit?
    iii) What is the function of both the labeled parts?

  • 3)

    A multicellular, filamentous alga exhibits a type of sexual life cycle in which the meiotic division occurs after the formation of zygote.State the ploidy of the gametophyte plant and gametangia.

  • 4)

    Honeybees produce their young ones only by sexual reproduction. Inspite of this, in a colony of bees we find both haploid and diploid individuals. Name the haploid and diploid individuals in the colony and analyse the reasons behind their formation.

  • 5)

    Fertilisation is not an obligatory event for fruit production in certain plants. Explain the statement.

CBSE 12th Standard Biology Subject Reproduction in Organisms Ncert Exemplar 3 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Offerings formed due to sexual reproduction have a better chance of survival, Why? Is this statement always true?

  • 2)

    The diagram given below shows a plant charm. Refer to the diagram and answer the questions that follow. Which types of sexuality does this plant have?

    ii) Give an example of any other plant which has same sexuality
    ii) Fill in the blanks in the given statement.
    Flowers with stamen are called______ flowers.
    Flowers with pistil are called____ flowers.

  • 3)

    Refer to the diagram given below and answer the questions that follow.

    i) Label the parts A and B
    ii) Which part of flower develops into seed and fruit?
    iii) What is the function of both the labeled parts?

  • 4)

    Which is a better mode of reproduction, sexual or asexual? why?

  • 5)

    Fertilisation is not an obligatory event for fruit production in certain plants. Explain the statement.

CBSE 12th Standard Biology Subject Reproduction in Organisms Ncert Exemplar 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Give reasons as to why cell division cannot be a type of reproduction in multicellular organisms.

  • 2)

    In haploid organism that undergo sexual reproduction, name the stage in the life cycle when meiosis occurs.  Give reasons for your answer.

  • 3)

    Given below are events that are observed in an artificial hybridisation programme. Arrange them in correct sequential order in which they are followed in hybridization programme.
    (a)Re-bagging (b)Selection of parents
    (c)Bagging (d) Dusting of pollen on stigma
    (e) Emasculation
    (f) Collection of pollen from male parent.

  • 4)

    Does self-incompatibility impose any restricions on autogamy ? Give reasons and suggest the method of pollination in such plants?

  • 5)

    Is it possible to consider vegetative propagation observed in certain plants like bryophyllum, water hyacinth, Ginger, etc. as a type of asexual reproduction? Give two/three reasons.

CBSE 12th Standard Biology Subject Reproduction in Organisms Ncert Exemplar 2 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Give reasons as to why cell division cannot be a type of reproduction in multicellular organisms.

  • 2)

    In haploid organism that undergo sexual reproduction, name the stage in the life cycle when meiosis occurs.  Give reasons for your answer.

  • 3)

    Which is the triploid tissue in a fertilised ovule? How is the triploid condition achieved?

  • 4)

    What are possible types of pollination in chasmogamous flowers. Give reasons.

  • 5)

    The number of taxa exhibiting asexual reproduction is drastically reduced in the higher plants (angiosperms) and higher animals (vertebrates) as compared with lower groups of plants and animals. Analyse the possible reasons for this situation.

CBSE 12th Standard Biology Subject Reproduction in Organisms Ncert Exemplar 1 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Mention two inhercent characteristics of Amoeba and yeast that enable them to reproduce asexually.

  • 2)

    Rearrange the following events of sexual reproduction in the sequence in which they occur in a flowering plant:
    Embryogenesis, Fertilisation
    Gametogenesis, Pollination

  • 3)

    Name the parts of the gynoecium which develop into fruit and seeds.

  • 4)

    Is the presence of large number of chromosomes in an organism a hindrance to sexual reproduction? Justify your answer by given suitable reason.

  • 5)

    Why do gametes produced in larg numbers in organisms exhibit external fertilization?

CBSE 12th Standard Biology Subject Reproduction in Organisms Ncert Exemplar 1 Marks Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Mention two inhercent characteristics of Amoeba and yeast that enable them to reproduce asexually.

  • 2)

    Between an annual and a perennial plant, which one has a shorter juvenile phase?  Give one reason.

  • 3)

    Rearrange the following events of sexual reproduction in the sequence in which they occur in a flowering plant:
    Embryogenesis, Fertilisation
    Gametogenesis, Pollination

  • 4)

    Name the parts of the gynoecium which develop into fruit and seeds.

  • 5)

    Name the type of pollination in self-incompatible plants.

CBSE 12th Standard Biology Subject Reproduction in Organisms Ncert Exemplar MCQ Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Choose the correct statement from amongst the following:

  • 2)

    There is no natural death in single-celled organisms like Amoeba and bacteria because:

  • 3)

    Identify the correct statement.

  • 4)

    Which of the following is a post-fertilisation event in flowering plants?

  • 5)

    Vegetative propagation in Pistia occurs by

CBSE 12th Standard Biology Subject Reproduction in Organisms Ncert Exemplar MCQ Questions 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Offsprings formed by sexual reproduction exhibit more variation than those formed by asexual reproduction because:

  • 2)

    Choose the correct statement from amongst the following:

  • 3)

    There are various types of reproduction. The type of reproduction adopted by an organism depends on:

  • 4)

    Identify the correct statement.

  • 5)

    Vegetative propagation in Pistia occurs by

CBSE 12th Standard Biology Subject Ncert Exemplar 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Discuss the mode of action and advantages/disadvantages of hormonal contraceptives.

  • 2)

    Do you justify the statutory ban on amniocentesis in our country? Give reasons.

  • 3)

    You have studied the story of Pepper moths in England. Had the industries been removed, what impact would it have on the moth population? Discuss.

  • 4)

    Two organisms occupying particular geographical area show similar adaptive strategies. Taking examples, describe the phenomenon.

  • 5)

    The following diagrams are the age pyramids of different populations. Comment on the status of these populations.

CBSE 12th Standard Biology Subject Ncert Exemplar 5 Marks Questions 2021 Part - II - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    What roles does pituitary gonadotrophins play during follicular and ovulatory phases of menstrual cycle? Explain the shifts in steroidal secretions. 

  • 2)

    Do you justify the statutory ban on amniocentesis in our country? Give reasons.

  • 3)

    (a) The shift from grain to meat diets creates more demands for cereals. Why?
    (b) A 250 kg cow produces 200 g of protein per day but 250 g of Methylophillus methylotrophus can produce 25 tonnes of protein. Name this emerging area of research. Explain its benefits.

  • 4)

    "Modern methods of breeding animals and plants can alleviate the global food shortage". Comment on the statement and give suitable examples.

  • 5)

    Can you think of a scientific explanation, besides analogy used by paul Ehrlich, for the direct relationship between diversity and stability of an ecosystem?

CBSE 12th Standard Biology Subject Ncert Exemplar 5 Marks Questions 2021 Part - I - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    What roles does pituitary gonadotrophins play during follicular and ovulatory phases of menstrual cycle? Explain the shifts in steroidal secretions. 

  • 2)

    The zygote passes through several development stages till implantation.Describe each stage briefly with suitable diagrams.

  • 3)

    Discuss the mode of action and advantages/disadvantages of hormonal contraceptives.

  • 4)

    Do you justify the statutory ban on amniocentesis in our country? Give reasons.

  • 5)

    Rose plants produce large, attractive bisexual flowers but they seldom produce fruits. On the other hand Lady's finger produces plenty of fruits. Analyse the reasons for failure of fruit formation in rose.

CBSE 12th Standard Biology Subject Ncert Exemplar 3 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Meiotic division during oogenesis is different from that in spermatogenesis. Explain how and why?

  • 2)

    The evolutionary story of moths in England during industrialization reveals, that "evolution is apparently reversible". Clarify this statement.

  • 3)

    Comment on the statement that "evolution and natural selection are end result of consequences of some other processes but themselves are not processes.

  • 4)

    What could have triggered mass extinction of species in the past?

  • 5)

    What does 'red' indicate in the IUCN red list (2004)?

CBSE 12th Standard Biology Subject Ncert Exemplar 3 Marks Questions 2021 Part - II - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    How do you express the meaning of worlds like race, breed cultivars or variety?

  • 2)

    Enumerate three characteristic criteria for designating a Mendelian population.

  • 3)

    Discuss the significance of heavy isotope of nitrogen.in Melson and Stahl's experiment.

  • 4)

    Study the given figure carefully and answer the following question:
    (i) Label the parts marked as (a), (b), (c), (d) and (e).
    (ii) Give one major function of each part.

  • 5)

    Name the blank spaces a,b,c and d from the table given below

    Name of crop Hybrid variety Resistance to diseases/pests
    a Himgiri Leaf and stripe rust, hill bunt
    Mustard b Aphids
    Cowpea Pusa komal c
    Chilli Pusa Sadabahar d

CBSE 12th Standard Biology Subject Ncert Exemplar 3 Marks Questions 2021 Part - I - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Meiotic division during oogenesis is different from that in spermatogenesis. Explain how and why?

  • 2)

    In peas, tallness is dominant over dwarfness and red colour of flowers is dominant over the white colour.  When a tall plant bearing red flowers was pollinated with a dwarf plant bearing white flowers, the different phenotypic groups were obtained in the progeny in human mentioned against them:
    Tall, Red = 138
    Tall, White = 132
    Dwarf, Red = 136
    Dwarf, White = 128
    Mention the genotypes of the two parents and of the four offspring types.

  • 3)

    With help of an example, differentiate between incomplete dominance and codominance.

  • 4)

    How was it conclused that genes are located on chromosome?

  • 5)

    Differentiate between diagnostics and therapeutics. Give one example for each category.

CBSE 12th Standard Biology Subject Ncert Exemplar 2 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Is there a relation between the size of an organism and its life span? Give two examples in support of your answer.

  • 2)

    Give reasons as to why cell division cannot be a type of reproduction in multicellular organisms.

  • 3)

    Given below are the events that are observed in an artificial hybridisation programme. Arrange them in the correct sequential order in which they are followed in the hybridisation programme.
    (a) Rebagging
    (b) Selection of parents
    (c) Bagging
    (d) Dusting the pollen on stigma
    (e) Emasculation 
    (f) Collection of pollen from male parent.

  • 4)

    What could be the reason for the fast rate of decomposition in the tropics?

  • 5)

    A part from plants and animals,microbes form a permanent biotic component in an ecosystem.While plants have been referred to as autorophs and animals a sheterotrophs,How do microbes fulfil their energy requirements?

CBSE 12th Standard Biology Subject Ncert Exemplar 2 Marks Questions 2021 Part - II - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    How are alleles of a particular gene different from each other? Explain its significance.

  • 2)

    If a father and son are both defective in red-green colour vision, is it likely that the son inherited the trait from his father?  Comment.

  • 3)

    List three strategies that a bisexual chasmogamous flower can evolve to prevent self pollination (autogamy).

  • 4)

    Define the term 'stress' for plants, Discuss briefly the two types of stress encountered by plants.

  • 5)

    Categories the following plants into hydrophytes, halophytes, mesophytes and xerophytes. Give reasons for your answers.
    (a) Salvinia      
    (b) Opuntia
    (c) Rhizophora
    (d) Mangifera.

CBSE 12th Standard Biology Subject Ncert Exemplar 2 Marks Questions 2021 Part - I - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Why are menstrual cycles absent during pregnancy?

  • 2)

    Name the type of pollination in self-incompatible plants.

  • 3)

    In case of polyembryony, if an embryo develops from the synergid and another from the nucellus, which is haploid and which is diploid? 

  • 4)

    Given below are the events that are observed in an artificial hybridisation programme. Arrange them in the correct sequential order in which they are followed in the hybridisation programme.
    (a) Rebagging
    (b) Selection of parents
    (c) Bagging
    (d) Dusting the pollen on stigma
    (e) Emasculation 
    (f) Collection of pollen from male parent.

  • 5)

    What are the functions of the two male gametes produced by each pollen grain in angiosperms?

CBSE 12th Standard Biology Subject Ncert Exemplar 1 Mark Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Mention the importance of LH surde during menstrual cucle.

  • 2)

    What is the significance of ampullaryisthmic junction in the female reproductive tract?

  • 3)

    What is the cross between the progeny of F1 and the homozygous recessive parent called? How is it useful?

  • 4)

    Even if a character shows multiple allelism an individual will only have two allels for that character.  Why?

  • 5)

    Why are proteins synthesised from spirulina called single cell proteins?

CBSE 12th Standard Biology Subject Ncert Exemplar 1 Mark Questions 2021 Part -II - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Name the part of gynoecium that determines the compatible nature of pollen grain.

  • 2)

    Mention two inhercent characteristics of Amoeba and yeast that enable them to reproduce asexually.

  • 3)

    Between an annual and a perennial plant, which one has a shorter juvenile phase?  Give one reason.

  • 4)

    A cross between two tall plants resulted in offspring, having few dwarf plants.  What would be the genotypes of both the parents?

  • 5)

    Two genes 'A' and 'B' are linked.  In a dihybrid cross involving these two genes, the F1 heterozygote is crossed with homozygous recessive parental type (aabb).  What would be the ratio of offspring in the next generation?

CBSE 12th Standard Biology Subject Ncert Exemplar 1 Mark Questions 2021 Part - I - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    What is the difference between a primary oocyte and a secondary oocyte ?

  • 2)

    What is the significance of ampullaryisthmic junction in the female reproductive tract?

  • 3)

    Name the part of gynoecium that determines the compatible nature of pollen grain.

  • 4)

    Mention two inhercent characteristics of Amoeba and yeast that enable them to reproduce asexually.

  • 5)

    What is the cross between the progeny of F1 and the homozygous recessive parent called? How is it useful?

CBSE 12th Standard Biology Subject Ncert Exemplar MCQ Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Caffeine is a stimulant present in

  • 2)

    In fermentation of dough which is the main gas produced?

  • 3)

    Choose the correct answer regarding the ZIFT procedure?

  • 4)

    Methanogens do not produce

  • 5)

    Activated sludge should have the ability to settle quickly so that it can

CBSE 12th Standard Biology Subject Ncert Exemplar MCQ Questions 2021 Part - II - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Bio fertilisers include:

  • 2)

    Methanogens, growing anaerobically on cellulosic material, produce

  • 3)

    Caffeine is a stimulant present in

  • 4)

    Methanogens do not produce

  • 5)

    Activated sludge should have the ability to settle quickly so that it can

CBSE 12th Standard Biology Subject Ncert Exemplar MCQ Questions 2021 Part - I - by Shweta Sharma - Anantapur - May 24, 2021 - View & Read

  • 1)

    Bio fertilisers include:

  • 2)

    Caffeine is a stimulant present in

  • 3)

    Given below are the four methods and their modes of action in achieving contraception.Select their correct matching from the four options that follows.

    control measures

    		 Mode of Action
    (A) Pill 1.  Prevents sperms reaching cervix
    (B) Condom 2. Prevents implication
    (C)Vasectomy 3. Prevents ovulation 
    (D) Copper T 4. Semen contains no sperms

     

  • 4)

    Choose the correct answer regarding the ZIFT procedure?

  • 5)

    What would happen if oxygen availability to activated sludge flocs is reduced?

CBSE 12th Standard Biology Subject Microbes in Human Welfare Case Study Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    Antibiotics produced by microbes are regarded as one of the most significant discoveries of the twentieth century. Antibiotics are the chemical substances which are produced by some microbes and can kill or retard the growth of other (diseasecausing) microbes.
    (a) Name the scientist who discovered the first antibiotic and the organism he was working on.
    (b) Name the first antibiotic and its source organism.
    (c) Name the scientists who established the potential of the above as an effective antibiotic.

  • 2)

    Rivers like Ganga, Cauvery, Yamuna, etc. are considered sacred rivers. Just because of this reason, the load of pollution in these rivers is increased as people throw into them many things in the name
    of puja. Many factories also let their effluents into the rivers.
    (a) What has the government done to check pollution in these rivers?
    (b) What does the BOD test measure in the water bodies?

  • 3)

    Cowdung and water is mixed and the slurry is fed into biogas plant for digestion by microbes. The person performing the process shares that there is no need to provide any inoculum to it.
    (a) Give reason why no inoculum is needed.
    (b) What is the role of the microbes at the source?
    (c) Mention the condition under which they will be most active and effective.

  • 4)

    Read the following and answer any four questions from (i) to (v) given below:
    Microorganisms include bacteria, viruses, fungi and protozoa. In our mind, we presume, most of the time, that microbes are always harmful. Microbes are, of course, the causal agents of many infections diseases of plants and animals including humans but they also have lots of beneficial role. Lactic acid bacteria (LAB) are one of this kind of useful group. These are Gram positive, non-sporulating, either rod shaped or spherical bacteria. They produce lactic acid in milk products as major metabolic end product of carbohydrate fermentation. LAB are considered as natural fermentors. Lactobacillus is a common LAB which converts lactose sugar of milk into lactic acid, that causes coagulation and partial digestion of milk protein casein. Milk is then changed into curd, yoghurt and cheese. Lactobacillus is also used in probiotics which have potentially beneficial effect on gut ecosystem of humans. Some other pro biotic strain used belong to the Genus Bifidobacterium.
    (i) Which of the following is not considered as microorganisms?

    (a) Bacteriophage (b) Streptococcus (c) Porphyra (d) Staphylococcus

    (ii) Select the incorrect option regarding the characteristics oflactic acid bacteria.

    (a) They are rod-shaped or spherical (b) They are Gram positive (c) They take part in carbohydrate fermentation. (d) They are acid intolerant

    (iii) Which of the following is not a lactic acid producing bacteria?

    (a) Streptococcus (b) Lactococcus (c) Saccharomyces (d) Enterococcus

    (iv) Probiotics are

    (a) gut friendly live bacteria (b) acid balancing alternated bacteria (c) beneficial amount of dead bacteria (d) Gram negative attenuated bacteria

    (v) Assertion: Lactobacillus bacteria do not retain crystal violet stain while staining.
    Reason: Lactobacillus have a very thin layer of peptidoglycan layer in their cell wall.
    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false.
    (d) Both assertion and reason are false.

  • 5)

    Read the following and answer any four questions from (i) to (v) given below:
    Alcohols are important industrial solvents. Ethanol, methanol, propanol and butanol are produced commercially by fermentation activity of some fungi, majorly yeasts. During fermentation, yeast cells convert cereal derived sugars into ethanol and CO2. At the same time hundreds of secondary metabolites that influence the aroma and taste of alcohol are produced. Sugar concentration affects the rate of fermentation reactions. Yeast cannot grow in very strong sugar solution. In case of complex carbohydrate containing nutrient media, 1% malt or Rhizopus is used along with yeasts. Hydrolysis of starch is carried out at high temperature for 30 mins. The crushed food mixed with hot water for obtaining malt in called mash. The nutrient medium prior to fermentation in called wort. Wort is cooled down to appropriate temperature and inoculated with strain of yeast.
    (i) The rate of alcohol production is measured on the basis of

    (a) amount of sugar present in the medium (b) amount of CO2 produced per unit time (c) amount of yeast added in the medium (d) all of these

    (ii) A number of chemicals are produced at the time of alcoholic fermentation with the change of nutrient media, pH and aeration. Select such by-product from the following.

    (a) Phenylethanol (b) Amyl alcohol (c) Glycerol (d) All of these

    (iii) During alcoholic fermentation of cereals and potato, the crushed food mixed with hot water for obtaining malt is called

    (a) juice (b) mash (c) wort (d) none of these

    (iv) Distilled alcohol with 95% ethanol content is called

    (a) absolute alcohol (b) rectified spirit (c) gin (d) brandy.

    (v) Assertion: Rhizopus or 1% malt is used in the nutrient medium when it contains complex carbohydrates.
    Reason: Yeast does not possess sufficient diastase or amylase.
    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false.
    (d) Both assertion and reason are false.

CBSE 12th Standard Biology Subject Microbes in Human Welfare Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    Antibiotics produced by microbes are regarded as one of the most significant discoveries of the twentieth century. Antibiotics are the chemical substances which are produced by some microbes and can kill or retard the growth of other (diseasecausing) microbes.
    (a) Name the scientist who discovered the first antibiotic and the organism he was working on.
    (b) Name the first antibiotic and its source organism.
    (c) Name the scientists who established the potential of the above as an effective antibiotic.

  • 2)

    Large quantities of sewage is generated everyday in cities and towns, which is treated in Sewage Treatment Plants (STPs) to make it less polluted. Given below is the flow diagram of one of the stages of STP. Observe the given flow diagram and answer the questions accordingly.

    (a) Why is the primary effluent passed into large aeration tanks?
    (b) Write the technical term used for the sediment formed. Mention its significance.
    (c) Explain the final step that results in the formation of biogas in the large tank before the treated effluent is released into water bodies.

  • 3)


    The diagram above is that of a typical biogas plant. Explain the sequence of events occurring in a biogas plant. Identify a, b and c.

  • 4)

    In agriculture, there is a method of controlling pests that relies on natural predation rather than on chemicals. An organic farmer believes that the more biodiversity a landscape has, the more sustainable it is.
    (a) Mention two disadvantages of using chemical methods to control pests.
    (b) Give an example of a bacterium and a fungus that are used as biocontrol agents.
    (c) An organic farmer does not eradicate the 'pests'. Give two reasons.

  • 5)

    Read the following and answer any four questions from (i) to (v) given below:
    Discovery of penicillin by Alexander Fleming in 1928 marked the beginning of the remarkable era in medical field. Penicillin was the first antibiotic extracted from Penicillium notatum. Antibiotics are used to treat bacterial diseases. These can be broad spectrum which can kill diverse group of disease causing bacteria and narrow spectrum which is effective only against one group of pathogenic strain. Antibiotics can act as bactericides or bacteriostatic. Bactericidal antibiotics kill bacteria by - disruption of cell wall synthesis (e.g., penicillin, cephalosporin, etc.), inhibition of 50S ribosome function (e.g., erythromycin), inhibition of 30S ribosome function (e.g., streptomycin, neomycin), inhibition of amino acid-tRNA binding to ribosome (e.g., tetracyline), etc. Bacteriostatic antibiotics do not kill the bacteria rather they restrict the growth of bacteria. Penicillin belongs to B-Iactum group of antibiotics and it inhibits bacterial cell wall synthesis by binding and inactivating protein. It inhibits transpeptidation of reaction and blocks cross-linking of the cell wall. It is used to treat tonsilitis, sore throat, gonorrhoea, rheumatic fever and some pneumonia types.
    (i) The first antibiotic was extracted from a

    (a) lichen (b) fungus (c) eubacteria (d) actinomycetes

    (ii) Which of the following kills bacteria by interfering 50S ribosome function?

    (a) Cephalosporin (b) Erythromycin (c) Streptomycin (d) Neomycin

    (iii) \(\beta \)-Iactum group of antibiotics kill the bacterial pathogen by

    (a) disruption of plasma membrane (b) inhibition of translation of mRNA (c) disruption of cell wall (d) inhibition of transcription of mRNA.

    (iv) Penicillin is not used to treat

    (a) pneumonia (b) tonsilitis (c) rheumatic fever (d) candidiasis

    (v) Assertion :Cephalosporins act by disruption of bacterial cell wall synthesis mechanism.
    Reason: Cephalosporins are bacteriostatic antibiotics.
    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false.
    (d) Both assertion and reason are false.

CBSE 12th Standard Biology Subject Environmental Issues Case Study Questions With Solution2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)


    Observe the diagram of the catalytic converter given above and answer the following questions.
    (a) Name the best fuel for vehicles fitted with catalytic converter. Justify your answer.
    (b) What happens to nitric oxide and carbon monoxide in the automobile exhaust, when passed through the catalytic converter?
    (c) Name any two metals used as catalyst in the catalytic converter.

  • 2)

    With the revolution of information technology, it has become an integral part of everyone's life, both in rural and urban India.
    (a) Write howe-wastes are generated?
    (b) How have the developed countries exploited the developing countries with respect to e-waste management?
    (c) Mention the correct solution for the treatment of e-wastes.

  • 3)

    Greenhouse effect is a naturally occurring phenomenon that is responsible for heating earth's surface and atmosphere. Earth's surface emits heat in the form of infrared radiation, but most of it is absorbed by certain gases, called greenhouse gases, leading to global warming.
    (a) Name two gases that contribute the most to global warming and mention their relative contribution towards this.
    (b) What would have been the temperature of earth without greenhouse effect?
    (c) What is the mean temperature ofthe earth now?

  • 4)

    Ozone gas is continuously formed by the action of UV rays on molecular oxygen and· also degraded into molecular oxygen. There should be a balance between the formation and degradation of ozone in the stratosphere.
    (a) What is meant by ozone hole?
    (b) Mention the unit to measure the thickness of ozone. 
    (c) When is the ozone hole formed each year?

  • 5)

    The degradation of natural resources can occur not only by the effects of pollutants but also by improper practices of resource utilisation. For example, the formation of fertile top soil takes centuries, but it is removed very easily (soil erosion) due to certain human activities.
    (a) Write any four such human activities that lead to soil erosion.
    (b) Mention two such problems that have come in the wake of Green Revolution.

CBSE 12th Standard Biology Subject Environmental Issues Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    Looking at the deteriorating air quality because of air pollution in many cities of our country, the citizens are very much worried and concerned about their health. The doctors have declared health emergency in the cities, where the air quality is very poor/hazarduous.
    (a) Mention any two major causes of air pollution.
    (b) Write any two harmful effects of air pollution on plants.
    (c) Mention any two factors on which the harmful effects of air pollution on organisms depend.

  • 2)

    In 1990s, due to the enormous vehicular traffic, Delhi ranked fourth among the most polluted cities of the world. The remedial measures taken by the Delhi Government brought marked improvement in the air quality by 2005
    (a) Mention any four measures taken by the Delhi Government that reduced vehicular air pollution in Delhi.
    (b) What is the norm set by Euro II for petrol and diesel vehicles?.

  • 3)

    Greenhouse effect is a naturally occurring phenomenon that is responsible for heating earth's surface and atmosphere. Earth's surface emits heat in the form of infrared radiation, but most of it is absorbed by certain gases, called greenhouse gases, leading to global warming.
    (a) Name two gases that contribute the most to global warming and mention their relative contribution towards this.
    (b) What would have been the temperature of earth without greenhouse effect?
    (c) What is the mean temperature ofthe earth now?

  • 4)

    Ozone gas is continuously formed by the action of UV rays on molecular oxygen and· also degraded into molecular oxygen. There should be a balance between the formation and degradation of ozone in the stratosphere.
    (a) What is meant by ozone hole?
    (b) Mention the unit to measure the thickness of ozone. 
    (c) When is the ozone hole formed each year?

  • 5)

    The degradation of natural resources can occur not only by the effects of pollutants but also by improper practices of resource utilisation. For example, the formation of fertile top soil takes centuries, but it is removed very easily (soil erosion) due to certain human activities.
    (a) Write any four such human activities that lead to soil erosion.
    (b) Mention two such problems that have come in the wake of Green Revolution.

CBSE 12th Standard Biology Subject Biotechnology: Principles and Processes Case Study Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    A schematic representation of the steps in Polymerase Chain Reaction (PCR) is shown below. Answer the questions that follow:

    (a) Name the steps A and D in the PCR.
    (b) Identify B. What are they chemically?
    (c) What is C? Name its source organism.

  • 2)

    Read the following and answer any four questions from (i) to (v) given below:
    Gene manipulation is a fast emerging science. It started with development of recombinant DNA molecule. It is named variously as DNA manipulation biotechnology, recombinant DNA technology and genetic engineering. This technology, that mostly involves cutting and pasting of desired DNA fragments, is based on two important discoveries in bacteria, i.e., presence of plasmid in bacteria and restriction endonucleases. Paul Berg was able to introduce a gene of SV-40 into a bacterium. The science of recombinant DNA technology took birth when Cohen and Boyer (1973) were able to introduce a piece of gene containing foreign DNA into plasmid of E.coli.
    (i) Biotechnology is also known as

    (a) DNA manipulation biotechnology  (b) recombinant DNA technology
    (c) genetic engineering  (d) all of these.

    (ii) A bacterial plasmid is a/an

    (a) extra chromosomal material that do not replicate  (b) extra chromosomal material that undergo replication with or without chromosomal DNA
    (c) tubular structures that help in conjugation  (d) bristle like solid structure that help in adhesion.

    (iii) Father of genetic engineering is

    (a) Paul Berg (b) Arber (c) Nathan (d) Smith.

    (iv) Which of the following is used by Paul Berg to introduce a gene of SV-40 in a bacterium?

    (a) E. coli  (b) cos-plasmids  (c) Lambda phage  (d) None of these

    (v) Read the given statements and select the correct option.
    Assertion : Biotechnology started with the development of recombinant DNA molecule.
    Reason : Biotechnology mostly involves cutting and pasting of desired DNA fragments.

    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false.
    (d) Both assertion and reason are false.
  • 3)

    Read the following and answer any four questions from (i) to (v) given below:
    The foundations of recombinant DNA (rDNA) were laid by the discovery of restriction enzymes. These enzymes are present in many bacterias where they function as a part of their defense mechanism called the Restriction Modification system (RM system). Molecular basis of this system was explained first by Werner Arber in 1962. The Restriction t-'l0dification system consists of two components:
    1. A restriction enzyme (called restriction endonuclease) identifies the introduced foreign DNA and cuts it into pieces.
    2.The second component is a modification enzyme (methylase) that adds a methyl group to DNA at specific site to protect it from the restriction enzyme cleavage.
    (i) Restriction endonucleases are enzymes present in (i) where they function as a part of (ii) mechanism.

    (a) (i) bacteria (ii) digestive  (b) (i) protists (ii) transcription  (c) (i) plant cells (ii) replication  (d) (i) prokaryotes (ii) defence

    (ii) Which of the following statements regarding modification enzyme is correct?

    (a) It adds methyl group to one or two bases usually within the host DNA sequence to protect it from the restriction enzyme.
    (b) It adds ethyl group to one or two bases usually within the sequence recognised by the restriction enzymes.
    (c) It adds methyl group to only one of bases within the foreign DNA sequence that is recognised by the restriction enzymes.
    (d) None of these

    (iii) Which of the following is a type II restriction enzyme?

    (a) Alu I  (b) EcoR I  (c) BamH I  (d) All of these

    (iv) Which of the following is the first discovered restriction endonuclease?

    (a) Sal I  (b) EcoR I  (c) Hind II  (d) EcoR II

    (v) Components of Restriction Modification System include

    (a) restriction enzyme  (b) modification enzyme  (c) lysing enzyme  (d) both (a) and (b).
  • 4)

    Read the following and answer any four questions from (i) to(v) given below:
    In recombinant DNA technology, the fragments of DNA generated after cutting the DNA by restriction enzymes are separated according to their size or length by gel electrophoresis. Gel electrophoresis is performed in a gel matrix so that molecules of similar electric charges can be separated on the basis of size. Most commonly used matrix in gel electrophoresis is agarose. The fragments are separated under the influence of electric field. The separated DNA fragments can be seen only after staining the DNA with compound known as ethidium bromide (EtBr) followed by exposure to UV radiation as bright orange band.
    (i) Gel electrophoresis is used for the separation of

    (a) DNA only  (b) DNA and RNA only
    (c) DNA and proteins only  (d) DNA, RNA and proteins.

    (ii) Most commonly used matrix is (i) which is a (ii) extracted from (iii).

    (a) (i) agarose (ii) polysaccharide (iii) sea weed  (b) (i) agarose (ii) protein (iii) sea weed
    (c) (i) EtBr (ii) polysaccharide (iii) sea weed  (d) (i) EtBr (ii) protein (iii) bacteria

    (iii) A DNA molecule was treated with a restriction endonuclease and three fragments of size (i) 426 kb, (ii) 129 kb and (iii) 46 kb were obtained. Identify the order in which these bands will arrange themselves in the gel plate after gel electrophoresis is completed. (Assuming that negative part of electrode is towards the well)

    (a) (iii) ➝ (ii) ➝ (i)  (b) (i) ➝ (ii) ➝(iii)  (c) (i) ➝ (iii) ➝ (ii)  (d) (iii) ➝ (i) ➝ (ii)

    (iv) Which of the following statements regarding gel electrophoresis is incorrect?

    (a) Separated DNA fragments can be seen only after staining DNA with EtBr.  (b) DNA fragments are separated according to their size.
    (c) Under the influence of electric field, positively charged molecules move towards the anode and negatively charged molecules move towards the cathode.  (d) None of these

    (v) The factor that will not affect the rate of DNA migration in gel electrophoresis is

    (a) size of DNA molecule  (b) concentration of DNA  (c) voltage supplied  (d) concentration of the gel
  • 5)

    Read the following and answer any four questions from (i) to (v) given below:
    The DNA, which is transferred from one organism into another by joining it with the vehicle DNA is called passenger or foreign DNA. Generally three types of passenger DNAs are used. These are complementary DNA (cDNA), synthetic DNA (sDNA) and random DNA. Complementary DNA (cDNA) is synthesized on RNA template (usually mRNA) with the help of reverse transcriptase. Synthetic DNA (sDNA) is synthesized on DNA template or without a template. Random DNA are small fragments formed by breaking a chromosome of an organism in the p.resence of restriction endonucleases.

    (i) Reverse transcriptase enzyme was discovered by

    (a) Temin and Baltimore (b) Cohen and Boyer (c) Arber and Nathan (d) Paul Berg.

    (ii) During cDNA formation, what would happen if DNA formed by reverse transcriptase is not treated with the alkali?

    (a) cDNA will not be digested (b) mRNA will not be digested
    (c) Hydrogen bonds will not form between base pairs  (d) mRNA will not be formed.

    (iii) Enzyme that helps in the formation of double stranded cDNA is

    (a) DNA synthetase (b) ligase (c) DNA polymerase (d) helicase.

    (iv) DNA polymerase can be obtained form

    (a) retrovirus (b) Agrobacterium (c) tobacco mosaic virus (d) Thermus aquaticus

    (v) DNA synthesised without a template is referred to as

    (a) complementary DNA (b) random DNA (c) synthetic DNA (d) Z-DNA

CBSE 12th Standard Biology Subject Biotechnology: Principles and Processes Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)


    (a) Name the particular technique in Biotechnology, whose steps are shown in the figure.
    (b) Name the steps 1 to 4 marked in the figure.
    (c) Give an example where a human gene product is. obtained from transgenic bacteria.

  • 2)

    (a) Name and write the significance of enzyme X.
    (b) Name and write the role of enzyme Y.
    (c) Name the processes A and B.

  • 3)

    Restriction enzymes typically recognize a symmetrical sequence of DNA.

    Notice that the top strand is the same as the bottom strand, but reads backward. When the enzyme cuts the strand between G and A, it leaves overhanging chains:

    (a) What is this symmetrical sequence of DNA known as?
    (b) What is the significance of these overhanging chains?
    (c) Name the restriction enzyme that cuts the strand between G and A.

  • 4)

    The following diagram illustrates the linking of DNA fragements. Answer the questions that follow the illustration.

    (a) Name 'a' and 'b'.
    (b) Complete the palindrome, which is recognised by EcoRI.
    (c) Name the enzyme that can link the two DNA fragments.

  • 5)


    (a) What does the diagram given above, depict?
    (b) What is meant by 'largest' and 'smallest' in the diagram'?
    (c) Name the compound used to visualise them.
    (d) Define elution.

CBSE 12th Standard Biology Subject Biodiversity and Conservation Case Study Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    Read the following and answer any four questions from (i) to (v) given below:
    The Kakapo is the world's largest and heaviest parrot, found only in New Zealand. It is unusual in that it is nocturnal, flightless and ground-dwelling. It is an excellent climber of trees, has strong legs that allow it to "jog" several kilometres in a single trip, and has mossy green plumage mottled with brown and yellow. The Kakapo is also critically endangered as of now, there were only few known living individuals left.
    (i) Which could be the possible reason for Kakapo to be well-adapted to its environment prior to the arrival of humans in New Zealand?

    (a) Kakapo was active only in the night when its potential predators would not be out for hunting.
    (b) The Kakapo would likely be well-camouflaged among the forest foliage due to its greenish plumage.
    (c) It was able to effectively hunt for food in the night.
    (d) All of these

    (ii) When humans started to settle in New Zealand, they took with them non-native animals, including mammals such as cats, dogs and stoats. By which of the following ways, human settlement likely contributed to a near decimation of Kakapo populations in New Zealand?

    (a) Habitat destruction  (b) Alien species invasion  (c) Pollution  (d) Both (a) and (b)

    (iii) All known survived Kakapo have been relocated by the New Zealand government to three predator-free islands, where they are monitored year round by staffs and volunteers to ensure that the birds are safe, healthy and well-fed. The extremely low population of Kakapo is a hurdle to the species becoming viable in the long term, despite such dedicated conservation efforts. This is because

    (a) the small population results in very small gene pool
    (b) there would be very limited genetic diversity among the resulting offspring.
    (c) of reduced capacity of the species to adapt and survive changes in the environment.
    (d) All of these

    (iv) The reasons behind conserving biodiversity have been grouped into which of the following categories?

    (a) Narrowly utilitarian  (b) Broadly utilitarian  (c) Ethical  (d) All of these

    (v) One of the ex situ conservation methods for endangered species is

    (a) wildlife sanctuaries  (b) biosphere reserves  (c) cryopreservation  (d) national parks.
  • 2)

    Read the following and answer any four questions from (i) to (v) given below:
    Edward Wilson described diversity at all levels of biological organisation ranging from macromolecules inside the cells to biomes. It is of three inter-related hierarchial levels-genetic diversity, species diversity and community ecosystem diversity. Species diversity is the variety in the number and richness of the species of a region. For example, the Western ghats have a greater amphibian species diversity than the Eastern ghats.
    (i) The number of species per unit area is called

    (a) species evenness  (b) species richness  (c) species equitability  (d) both (a) and (c).

    (ii) The table below gives the population (in thousands) of ten species (A - J) in four  areas (I - IV) consisting of the number of habitats given within brackets against each. Study the table and answer the question which follows:

    Area and
    number of
    habitats    		 Species and their population (in thousands) in the area
      A B C D E F G H I J
    I(11) 23 12 0.52 6.0 - 3.1 1.1 9.0 - 10.3
    II(11) 10.2 - 0.62 - 1.5 3.0 - 8.2 1.1 11.2
    III(13) 11.3 0.9 0.48 2.4 1.4 4.2 0.8 8.4 2.2 4.1
    IV(12) 3.2 10.2 1.1 4.8 0.4 3.3 0.8 7.3 1.3 2.1

    Which are out of I to IV shows maximum species diversity?

    (a) II  (b) III  (c) IV  (d) I

    (iii) Study the given populations and choose the correct answer in relation to species diversity.

    Population Species Group Individuals
    Population A I Mammals 3
    II Birds 2
    III Amphibians 2
    Population B I Mammals 2
    II Mammals 2
    III Amphibians 1
    Population C I Mammals 3
    II Mammals 2
    III Mammals 1

    Maximum diversity  Minimum diversity
    (a) Population B      Population C
    (b) Population A      Population C
    (c) Population A      Population B
    (d) Population B      Population A
    (iv) The concept of species diversity has two components : evenness and richness. Evenness is based on the relative abundance of species. Richness is based on the total number of species present. Diversity indices combine a measure of richness and evenness. The Simpson index (D) is calculated from the following equations:
    \(D=\sum_{i=1}\left(n_{i} / N\right)^{2}\)
    where, n = total number of organisms of particular species
    N = total number of organisms of all species
    Below are data collected in two terrestrial plant communities that represent part of a successional
    chronosequence. In this case the values were measured as percent cover.

    Early Successional Community Late Successional Community
    Species Percent Cover Species Percent Cover
    A 83 F 24
    B 5 G 20
    C 9 H 18
    D 2 I 23
    E 1 J 15

    The data indicate that, relative to the early successional community, the late successional community has which of the following characteristics?
    Species Richness           Evenness
    (a) Higher                        Higher
    (b) Higher                        Lower
    (c) Same                         Lower
    (d) Same                         Higher
    (v) Select the incorrect statement regarding species diversity.

    (a) It results in polymorph formation and is useful in adaptation to changes in environmental conditions.
    (b) Number of individuals of different species represent species evenness.
    (c)It influences biotic interactions and stability of the community.
    (d) It is a trait of the community.
  • 3)

    Read the following and answer any four questions from (i) to (v) given below:
    Non-native or alien species are often introduced in advertently for their economic and other uses. They often become invasive and drive away-the local species. Exotic species have proved harmful to both aquatic and terrestrial ecosystems. For example, water hyacinth (Eichhornia crassipes) was introduced in Indian waters to reduce pollution. It was clogged water bodies including wetlands at many places resulting in death of several aquatic plants and animals.
    (i) Island water ecosystem are the most vulnerable due to

    (a) small size  (b) small number of species  (c) increases reproductive capacity  (d) both (a) and (b).

    (ii) Which of the following is not an alien species?

    (a) Lantana camara  (b) Periplaneta americana  (c) Nile Perch  (d) Yucca moth

    (iii) Second major cause of species extinction is

    (a) habitat loss and fragmentation  (b) over exploitation  (c) alien species invasion  (d) co-extinction.

    (iv) Assertion: Eichhornia crassipes drains off oxygen from water and can be seen growing in standing water.
    Reason: Eichhornia crassipes is an indigenous species of India.

    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false.
    (d) Both assertion and reason are false.

    (v) The population of species P in a certain community was constant until a population species Q from a distant land was subsequently introduced into that community. The interaction between the two populations is reflected in the graph below.

    What could be the possible reason for the decrease in the population of species P over a number of days?

    (a) Species Q is a predator of species P.
    (b) Species Q.is a prey species which wiped out the population of species P.
    (c) Species P and Q compete for space but feeds on different food.
    (d) None of these
  • 4)

    Read the following and answer any four questions from (i) to (v) given below:
    Wetlands are called Ramsar sites because the first international convention on their conservation was held in Ramsar in Iran in 1971. Wetlands or Ramsar sites are low lying marshy areas which get filled up during rains due to runoff and overflow from other water bodies. They are often considered to be waste lands which are used as dumping area  and filled up to recover land for various constructions activities. As a result, a large number of wetlands have disappeared.
    (i) Select the incorrect match of wetland and its location.

    Wetland Location
    (a) Harike  Punjab
    (b) Chandra Tal  H.P.
    (c) Bhoj  M.P.
    (d) Ashtamudi  Odisha

    (ii) Migratory bird flamingo breeds in which of the following wetlands?

    (a) Bhitarkanika Mangroves  (b) Rann of Kutch  (c) Harike  (d) Chandra Tal

    (iii) Which of the following is not an importance of wetlands?

    (a) They are an important source of recharging groundwater.
    (b) They provide protection from floods.
    (c) They are good source of siltation and purification of water.
    (d) None of these

    (iv) Which of the following wetland ecosystem is highly acidic and has a accumulation of decomposed plants known as peat?

    (a) Bog  (b) Mangrove  (c) Estuary  (d) Watershed

    (v) The mangroves of Bhitarkanika are famous for

    (a) rare migratory waterbirds  (b) nesting sites for endangered olive ridley turtles  (c) prawn cultivation  (d) all of these.
  • 5)

    Read the following and answer any four questions from (i) to (v) given below :
    Excessive exploitation of species, whether a plant or animal reduces the size of its population so it becomes vulnerable to extinction. Such as Dodo and passenger pigeon have become extinct due to over exploitation by humans. Thus the world is facing accelerated rates of species extinctions, largely due to human interference.
    (i) Which of the following cause of biodiversity loss is not included in evil quartet?

    (a) Coextinction  (b) Pollution
    (c) Alien species invasion  (d) Habitat loss and fragmentation

    (ii) Identify the species that have become extinct due to over exploitation

    (a) Stellar sea cow  (b) Yucca moth
    (c) Blatta orientalis  (d) Nile Perch

    (iii) Factors which make species susceptible to extinction are

    (a) large population size  (b) lack of genetic variability
    (c) lower status of trophic level  (d) ability to switch over to alternate foods.

    (iv) Assertion: Pollution reduces species biodiversity.
    Reason: Spillover of oil in sea causes death of several marine animals.

    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false.
    (d) Both assertion and reason are false.

    (v) __________ is the first major cause of species extinction.

    (a) Coextinction  (b) Over exploitation  (c) Habitat destruction  (d) Alien species invasion.

CBSE 12th Standard Biology Subject Biodiversity and Conservation Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    The global animal diversity is shown in the pie charts (A-Invertebrates and B-vertebrates) drawn below.
    Answer the questions that follow.

    (a) Name the animal groups that are represented by the areas shaded black in A and B, respectively. Also, mention the kind of habitat, where you would find these groups of animals.
    (b) Identify the following groups of animals in the pie diagrams: Crustaceans and Amphibians.

  • 2)

    The following graph shows the species area relationship.

    Answer the following questions as asked.
    (i) Write the equations for the curves a and b.
    (ii) Name the naturalist who showed this kind of relationship.
    (iii) Name the region he explored.

  • 3)

    When a graph showing species-area relationship on a logarithmic scale, the relationship is a straight line. Ecologists have discovered that the value of z-line lies in the range of 0.1 and 0.2 irrespective of the taxonomic group or the region.
    (a) When will the stope become much steeper with higher Z-values? Give an example.
    (b) What do steeper slopes mean in this context?

  • 4)

    It is learnt from the study of the history of life on earth through fossil records that there were large scale losses of species. Since the orgin and diversification of life forms on the earth, there were five episodes of mass extinction. The 'Sixth Extinction' is presently in progress.
    (a) Give two points as to how this sixth episode is different from the earlier episodes.
    (b) What do the ecologists warn about the current trend?
    (c) Mention the three effects of loss of biodiversity in a region.

  • 5)

    Faced with conflict between development and conservation, many nations find it unrealistic and economically not feasible to conserve all their biological wealth. On a global basis, eminent conservationists have identified certain regions as 'Biodiversity hotspots' for maximum protection.
    (a) Mention two criteria for a region to be called a 'biodiversity hotspot'.
    (b) Name two biodiversity hotspots in India.
    (c) Hotspots occupy less than 2 per cent of the earth's land area. Yet, they are given priority for conservation of biodiversity. Give two reasons.

CBSE 12th Standard Biology Subject Ecosystem Case Study Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    An ecosystem can be visualised as a functional unit in nature, where living organisms interact among themselves and with the surrounding physical environment also. The interaction of the biotic and abiotic components results in a physical structure that is characteristic of an ecosystem.
    (a) Name the two features that define the structural aspect of an ecosystem.
    (b) Mention the four common functional aspects of an ecosystem.

  • 2)

    A pond is a shallow water body, which is fairly a self-sustainable unit that explains the complex interactions in an aquatic ecosystem. The water with all the dissolved inorganic and organic nutrients is the major abiotic component.
    Name the three groups of biotic components in the pond and give an example for each.

  • 3)

    The fallen parts of plants such as leaves, flowers, etc., faecal matter of animals, dead remains of animals, etc. are ultimately broken down into simpler inorganic nutrients, carbon dioxide and water.
    1. Fragmentation, 2. Leaching, 3. Catabolism are some important steps in the process; they occur simultaneously.
    (a) What term is given to the group of organisms that carry out the steps 1 and 3, respectively and give an example for each.
    (b) Name the other two steps involved in the process.

  • 4)

    Organisms occupy a specific place in their natural surroundings or in a community according to their feeding relationship with the other organisms. Based on the source of nutrition of food organisms occupy a particular place, called trophic level, in a food chain.
    (a) What technical term is given to the organisms occupying the first, second and third trophic levels in a food chain?
    (b) Choose an example for each of the above trophic levels, from the following list of organisms: Rabbit, Wolf, phytoplanktons, frog, snail, Hydrilla, jackal.

  • 5)

    Over the years, it has been observed that some of the lakes are disappearing due to urbanisation. In the absence of human interference, depict through a flow chart, how the successional series progresses from hydric to mesic condition.

CBSE 12th Standard Biology Subject Ecosystem Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    An ecosystem can be visualised as a functional unit in nature, where living organisms interact among themselves and with the surrounding physical environment also. The interaction of the biotic and abiotic components results in a physical structure that is characteristic of an ecosystem.
    (a) Name the two features that define the structural aspect of an ecosystem.
    (b) Mention the four common functional aspects of an ecosystem.

  • 2)

    Organisms occupy a specific place in their natural surroundings or in a community according to their feeding relationship with the other organisms. Based on the source of nutrition of food organisms occupy a particular place, called trophic level, in a food chain.
    (a) What technical term is given to the organisms occupying the first, second and third trophic levels in a food chain?
    (b) Choose an example for each of the above trophic levels, from the following list of organisms: Rabbit, Wolf, phytoplanktons, frog, snail, Hydrilla, jackal.

  • 3)


    A part of an aquatic ecosystem is represented in the picture provided above.
    (a) Mention the relationship between  and  with respect to population interaction

    (c) Construct a food chain operating in this ecosystem.

  • 4)


    Pyramids of Biomass of two types are shown in the diagram given above.
    Answer the following questions.
    (a) Identify the type of ecosystems in which the pyramid of biomass A and B occur, respectively.
    (b) Why is the pyramid A inverted and B upright?

  • 5)

    Over the years, it has been observed that some of the lakes are disappearing due to urbanisation. In the absence of human interference, depict through a flow chart, how the successional series progresses from hydric to mesic condition.

CBSE 12th Standard Biology Subject Organisms and Populations Case Study Questions With Solutions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    The graph given below depicts the organismic response to changing external environmental conditions. According to their response, the organisms are grouped into two types.

    Answer the following questions.
    (a) Name the group of organisms, which will show pattern A. Give an example.
    (b) ame the group of organisms, which will show pattern B. Give an example.
    (c) Define homeostasis.

  • 2)

    'The population of a metro city experiences fluctuations in its population density over a period of time'.
    (a) When does the population in a metro city tend to increase?
    (b) When does the population in a metro city tend to decline?
    (c) If 'N' is the population density at the time 't', write the population density at the time 't + l'.(Delhi 2020).

  • 3)

    If in a population of size 'N', the birth rate is represented as 'b' and the death rate as 'd', the increase or decrease in 'N' during a unit time period 't' will be
    dN/dt = (b - d) x N
    The equation given above can also be represented as
    dN/dt = r x N, where r = (b - d).
    (a) What does 'r' represent in the above?
    (b) Write anyone significance of calculating 'r' for any population.
    (c) In a pond there are 100 frogs. 20 more were born in a year. Calculate the birth rate of this population.

  • 4)

    There is no natural habitat on earth, which is occupied by a single species. In nature, plants, animals and microbes do not and cannot live in isolation. Interspecific interactions arise from the interaction of populations of two different species.
    (a) Even a plant species, which makes its own food cannot live alone. Give two examples, where plants depend on other species for survival.
    (b) Name the type of interspecific interaction seen in each of the following examples.
    (i) Disappearance of smaller barnacles when Balanus dominated intertidal area of the sea coasts of Scotland.
    (ii) Clown fish living among the stinging tentacles of sea anemone.
    (iii) The Wasp species pollinating a fig inflorescence.
    (iv) Cuscuta growing on hedge plants.

  • 5)

    It is generally believed that competition occurs only when closely related species compete for the same resources that are limiting.
    Give two examples to show that the above statement is not always true.

CBSE 12th Standard Biology Subject Organisms and Populations Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    The graph given below shows the distribution of the major biomes of the world.

    Answer the following questions based on the graph.
    (a) Identify the biomes A, D, E, F.
    (b) Which of the biomes shows the maximum range of
    (i) Mean annual precipitation
    (ii) Mean annual temperature?

  • 2)

    Study the three representative figures of age pyramids relating to human population and answer the questions that follow:

    (a) Wrrte'the names given to the three kinds of age pyramids, (I), (il) and (iil).
    (b) Give reason for each, why you have named them so.

  • 3)


    (I) Which of the above process(es) represent(s) an increase in population?
    (ii) Which ofthe above process(es) represent(s) a decrease in population?
    (iii) If a new habitat is just being colonised, out of the four process(es) affecting the population growth, which one contributes the most?

  • 4)


    Study the population growth curves shown in the graph and answer the following questions.
    (i) Identify the growth curves 'a' and 'b'.
    (ii) Which one of them is considered more realistic and why?
    (iii) What does the dotted line in the graph indicate?

  • 5)

    Study the table given below and answer the questions that follow:

    (+ = Beneficial interaction)
    (- = Detrimental interaction)
    (0 = Neutral interaction)
    (i) Identify the type of interaction (a), (b), (c) and (d).
    (ii) Why are predators 'prudent' in nature?

CBSE 12th Standard Biology Subject Biotechnology and its Applications Case Study Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    After green revolution, now a stage has come when further increase in crop yield with the existing crop varieties is not possible. Use of agro-chemicals is two expensive for the farmers and are too harmful for animals and the environment. The answer to the questions whether there is a method to increase the yield and reduce the use of agro-chemicals, is the use of genetically modified (GM) crops.
    Write six points on the advantages ofthe GM crops.

  • 2)

    In mammals, insulin is synthcsised as a pro-hormone. Observe the diagram showing the maturation of pro-insulin into insulin given below and answer the questions that follow.

    (a) Why is it called pro-insulin?
    (b) Mention the chemical changes that the proinsulin undergoes to become the mature functional insulin.
    (c) What is the challenge in the production ofinsulin using rDNA techniques?

  • 3)

    A multinational company (XYZ) marketed a medicine extracted from medicinal herbs grown in the sprawling fields in a foreign country. This herb is found growing in our country only and no compensation was paid or permission taken from the relevant authority.
    (a) What is the term used to refer to such an act committed by the multinational company?
    (b) Justify the meaning of the term.
    (c) What has the Indian Government done to prevent such deeds?

  • 4)

    Read the following and answer any four questions from (i) to (v) given below:
    Transgenic cows have extra gene or genes inserted into their DNA. Firstly the genes for the desired product is identified and sequenced. Then a gene construct containing this desired gene is introduced into female cow cells. Transgenic bovine cells are selected and fused with bovine oocytes that have had all of their chromosomes removed. Once fused with the oocyte, the transgenic cells chromosomes are reprogrammed to direct development into an embryo which can be implanted into a recipient cow. The resulting transgenic cow only express the trans gene in her milk. This is because expression of the trans gene is controlled by a promoter specific to lactating mammary cells. The first transgenic cow was 'Rosie:
    (i) The gene construct with desired gene is introduced into female cow cells by

    (a) transformation  (b) transduction  (c) transfection  (d) transplantation.

    (ii) Production of transgenic cow fulfill the objective of

    (a) increased milk production  (b) increased meat production  (c) molecularfarming  (d) all of these

    (iii) The name of first transgenic cow is

    (a) Tracy  (b) Dolly  (c) Rosie  (d) AND!.

    (iv) Transgenic cow is produced through the implantation of _____containing transgene into recipient cow.

    (a) ova  (b) embryo  (c) mammary cell  (d) both (a) and (b)

    (v) Assertion : Transgenes only express in the mammary glands of transgenic cow.
    Reason : Transgenes are present in chromosomes of every cell in transgenic cow

    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion
    (c) Asgertion is true but reason is false.
    (d) Both assertion and reason are false.
  • 5)

    Read the following and answer any four questions from (i) to (v) given below:
    Insulin used to cure diabetes was earlier extracted from pancreas of slaughtered cattle and pigs. Insulin extracted from an animal source, though caused some patients to develop allergy or other types of reactions to the foreign protein. Human insulin consists of two short polypeptide chains: chain A and chain B, that are linked together by disulphide bridges. In mammals including humans, insulin is synthesised as a pro-hormone which contains an extra stretch called the C-peptide. This C peptide is not present in mature insulin and is removed during maturation into insulin.
    (i) Identify A in the given figure.
     
     

    (a) Polypeptide chain A  (b) Polypeptide chain B  (c) Polypeptide chain C  (d) None of these

    (ii) The following is a list of some stages involved in producing human insulin from genetically engineered bacteria.
    1. The bacteria are cultured in a fermenter for large scale production.
    2. Recombinant insulin is extracted from the bacterial cells that expresses insulin gene.
    3. The same restriction enzyme is used again to cut the bacterial plasmid for insertion of the human insulin gene.
    4. Bacteria take up the plasmid carrying the insulin gene.
    5. A restriction enzyme is used to cut human DNA to extract the insulin gene.
    Select the correct order of these stages.

    (a) 1,5,3,4,2  (b) 2,4,3,5,1  (c) 4,5,3,2,1  (d) 5,3,4,1,2

    (iii) To insert the insulin gene into bacterial DNA, both the bacterial plasmid and the human chromosome containing the insulin gene are treated with the same restriction enzyme. Using the same restriction enzyme ensures that

    (a) DNA ligase is able to join the segments of human and bacterial DNA
    (b) the exact length of nucleotides matching the insulin gene is removed from the plasmid
    (c) both the bacterial and human DNA will contain sticky ends
    (d) Sticky ends in the cut plasmid and insulin gene are complementary.

    (iv) Why is the fermentor important for the production of human insulin by transgenic bacteria

    (a) It provides optimal conditions for the transgenic to multiply rapidly.
    (b) It facilitates the extraction and purification of insulin from the transgenic bacteria.
    (c) It maximise the rate of fermentation of the transgenic bacteria.
    (d) It provides the low-oxygen conditions that are important for insulin production.

    (v) A bacteriologist carries out his first attempt at engineering E.coli with the gene for human insulin. During the process, he realises that his stock of DNA ligase has depleted but decides to continue anyway. What is a likely consequence of his decision?

    (a) Bacteria with the rDNA will not be able to form colonies in a fermenter
    (b) The resulting plasm ids are not able to enter the E.coli bacteria even after applying heat shock.
    (c) The resulting E.coli bacteria do not contain the human insulin gene.
    (d) The bacterial plasm ids do not have sticky ends and are unable to accommodate the human gene.

CBSE 12th Standard Biology Subject Biotechnology and its Applications Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    Two of the steps involved in producing nematoderesistant tobacco plants based on the process of RNAi are given. Write the missing steps in proper sequence in the blank spaces a, c, d, f, g and h provided.

  • 2)

    A child is born with a very weak immune system due to the deficiency of an enzyme; it is a hereditary disorder. The doctor explained the available methods of treatment and advised for gene therapy.
    (a) Identify the deficient enzyme and the cause of it.
    (b) What is gene therapy?
    (c) ame two other methods available for the treatment of this disease.

  • 3)

    Read the following and answer any four questions from (i) to (v) given below:
    Golden rice was engineered from normal rice by Potrykus and Beyer in the 1990s. The typical golden colour is due to the production of \(\beta\) carotene a precursor of vitamin - A. Golden rice differs from its parental strain by the addition of three \(\beta\) carotene genes. These included two genes from daffodil plant and third from a bacterium. The incorporation of these genes allows the rice plant to modify certain metabolic pathways in its cells to produce \(\beta\)-carotene.
    (i) Due to genetic modification golden rice plants produce and store \(\beta\) - carotene in

    (a) stem  (b) seed  (c) leaves  (d) all of these

    (ii) Transfer of genes to produce golden rice is achieved by

    (a) Agrobacterium  (b) pBR322  (c) \(\lambda \text { -phage }\)  (d) gene gun

    (iii) In golden rice two genes were taken from

    (a) Narcissus sp.  (b) Erwinia  (c) Coryza sativa  (d) none of these

    (iv) Golden rice is helpful to fight against disease caused by the deficiency of

    (a) Vitamin Bl2  (b) Vitamin C  (c) Vitamin A  (d) Vitamin D.

    (v) Golden rice was genetically engineered by

    (a) Fire and Mello  (b) Potrykus and Beyer  (c) Banting and Best  (d) Kohler and Milstein
  • 4)

    Read the following and answer any four questions from (i) to (v) given below:
    Transgenic animals can serve as factories that in some cases, may produce large amount of proteins more efficiently. Transgenic mice have been engineered to express human antibodies by introducing large segment of human DNA encoding human immunoglobulin genes. In transgenic large animals such as cow or sheep proteins of pharmaceutical value can be produced in large quantities in milk which is later purified. Transgenesis can be used to alter many phenotypic properties including growth rate, fat composition, milk production, hair texture, etc.
    (i) The production of transgenic animals includes

    (a) identification and separation of desired gene
    (b) combining the desired gene with appropriate vector
    (c) introduction of vector in cells, tissues or embryos
    (d) all of these.

    (ii) In transgenic animals, i.e., cow and sheep proteins of pharmaceutical value are produced in large quantities in the

    (a) blood   (b) accumulated fat  (c) mammary glands  (d) none of these.

    (iii) Mouse is mostly preferred animal for studies on gene transfer because
    A. short oestrous cycle
    B.long gestation period
    C.Short generation time
    D.Production of one or two offspring per pregnancy

    (a) both (A) and (C) (b) both (A) and (B) (C) Only D (d) both (C) and (D).

    (iv) Transgenic genes alter many phenotypic properties including

    (a) growth rate (b) fat composition (c) milk production (d) all of these

    (v) Assertion : Transgenic mice have been engineered to express human antibodies.
    Reason : Large segment of human DNA encoding human immunoglobulin have been transferred to mice.

    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false.
    (d) Both assertion and reason are false
  • 5)

    Read the following and answer any four questions from (i) to (v) given below:
    European patent office, Munich granted patent for fungicidal use of neem oil, to firm of WR. Grace & Co. It was challenged by Vandana Shiva and Ajay Phadke who had researched neem in India and it was shown that Grace & Co. had not unveiled any novelty factor in neerns properties. Ethics include rules of conduct by which a community regulates the behaviour and decides as to which activity is lawful and which is not.
    (i)_________ allow private, monopoly right over animals and plants.

    (a) Bioethics  (b) Biopatents  (c) Bioweapons  (d) Either (a) or(b)

    (ii) Which of the following is not a criteria of granting patent?

    (a) Novelty  (b) Utility  (c) Non-obviousness  (d) Prior art

    (iii) On which plants patents have been granted?

    (a) Piper nigrum  (b) Brassica campestris  (c) Punica granataum  (d) All of these

    (iv) Rules of conduct that may be used to regulate our activities in relation to biological world are included in

    (a) bioethics  (b) biopiracy  (c)biopatents  (d) biowar

    (v) Assertion : Genes and cells should not be patented.
    Reason : Genes and cells are not an inventions

    (a) Both assertion and reason are true and reason is the correct explanation of assertion
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion
    (c) Assertion is true but reason is false
    (d) Both assertion arid reason are false

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food ProductionCase Study Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    The steps in a programme are given below:
    (i) Collection of germplasm.
    (ii) Crossbreeding the selected parents.
    (iii) Selecting the superior recombinant progeny.
    (iv) Testing, release and commercialisation ofthe new cultivars.
    Answer the following qeustions:
    (a) What is this programme called?
    (b) Name two important qualities that form the basis of selection of the progeny.
    (c) What was the outcome of this programme?
    (d) What is the popular term given to this outcome? Name the Indian scientist who is credited with the chalking out this programme.

  • 2)

    More than 840 million people in the world do not have adequate food to meet their daily nutritional requirements. According to Global Hunger Index, 2014, about three billion people suffer from 'hidden hunger'.
    (a) Apply your knowledge of plant breeding techniques to suggest a programme to improve public health.
    (b) Specify four objectives of this programme.

  • 3)

    Life style diseases are increasing alarmingly in our country. We are facing large scale malnutrition also in the population.
    (a) Suggest a programme by which we can address these problems.
    (b) Give any two examples to support your answer.

  • 4)

    Demand for mushroom as food has led to its culturing on a large scale. Similarly, it is perceived that microbes too would become acceptable as food.
    (a) Identify a microbe which can be cultured as a food source .
    (b) Mention the advantages of its culture.

  • 5)

    Mr. Arjun Singh has a high quality banana plantation in his field; but the yield suffered due to infection of the plants by a virus.
    (a) Suggest a fast and efficient method to get a large number of healthy/virus-free plants in the next generation without compromising on the existing quality.
    (b) Justify the selection of your method.
    (c) Name two other plants that are produced on a commercial scale using this method.

CBSE 12th Standard Biology Subject Strategies for Enhancement in Food Production Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    Fisheries has an important place in Indian economy. It provides income to millions of fishermen and farmers, especially in the coastal states. In order to meet the increasing demand on fisheries, different techniques have been employed to increase production of fishes.
    (a) Name two such techniques employed to increase fish production.
    (b) What term is given to the movement being implemented in the same lines as Green Revolution.
    (c) Name two freshwater fishes very commonly used as food.

  • 2)

    More than 840 million people in the world do not have adequate food to meet their daily nutritional requirements. According to Global Hunger Index, 2014, about three billion people suffer from 'hidden hunger'.
    (a) Apply your knowledge of plant breeding techniques to suggest a programme to improve public health.
    (b) Specify four objectives of this programme.

  • 3)

    Life style diseases are increasing alarmingly in our country. We are facing large scale malnutrition also in the population.
    (a) Suggest a programme by which we can address these problems.
    (b) Give any two examples to support your answer.

  • 4)

    More than 25 per cent of human population is suffering from hunger and malnutrition. Conventional methods of agricultural production are not able to meet the demand of food at the rate which human population is increasing.
    (a) Mention an alternate source of proteins for human and animal nutrition.
    (b) Name any two microbes used as food supplements and explain their role.

  • 5)

    Demand for mushroom as food has led to its culturing on a large scale. Similarly, it is perceived that microbes too would become acceptable as food.
    (a) Identify a microbe which can be cultured as a food source .
    (b) Mention the advantages of its culture.

CBSE 12th Standard Biology Subject Human Health and Disease Case Study Questions With Solution - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    Study the diagram showing the entry of HIV into the human body and the processes that are followed:

    (a) Name the human cell 'A' HIV enters into.
    (b) Mention the genetic material 'B' HIV releases into the cell.
    (c) Identify enzyme 'C'

  • 2)


    The skeletal structure of a cannabinoid molecule is given above. Answer the following questions.
    (a) What are the modes of its consumption by humans?
    (b) Name the four different forms in which cannabinoids are produced.

  • 3)

    Read the following and answer any four questions from (i) to (v) given below:
    Rajesh, Ravi and Rohit are roommates. They are doing their graduation. Few months back Ravi fell ill. It took him around 3 weeks to recover. Both his friends were absolutely healthy at that time. After sometime Rajesh also fell ill from some other disease. This time Ravi and Rohit both contracted the same illness. Based on the above information, answer the following questions.
    (i) Which of the following holds true for Ravi's illness?

    (a) Ravi was suffering from a communicable disease that is transmitted through vector.
    (b) Ravi was suffering from a communicable disease that is transmitted through faecal oral route.
    (c) Ravi was suffering from a non-com'municable disease like anaemia.
    (d) Ravi was suffering from a non-communicable disease like Down's syndrome.

    (ii) Select the correct statement.

    (a) Ravi contracted a disease caused by air borne microbes. (b) Ravi could have suffered a nutritional disorder.
    (c) Ravi suffered a non-contagious disease. (d) Both (b) and (c)

    (iii) Which could be correctly said for Rajesh's illness?

    (a) Rajeshs illness was due to a microbial infection (b) Rajesh's illness could be contagious or non-contagious.
    (c) Rajesh's illness could be cured by antibiotics. (d) All of these

    (iv) Which of the following may depicts Ravi's and Rajeshs illness?

    Ravi Rajesh
    (a) Sickle cell anaemia Myocardial infection
    (b) Whooping cough Tetanus
    (c) Gastritis Rhinitis
    (d) Hypertension Thyroid

    (v) Assertion: Diabetes mellitus is a non-communicable disease which can be completely cured.
    Reason: Diabetes mellitus is caused by deficiency of aldosterone hormone.

    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false.
    (d) Both assertion and reason are false
  • 4)

    Read the following and answer any four questions from (i) to (v) given below:
    Priya was 4 years old when she contracted chicken pox. It took her around 15 days to recover completely. Now Priya is 5 years old so her mother got her vaccinated few days back for DPT (5th dose) as per immunisation program. Recently she was playing with her friend in the park when her friend accidently fell on iron pipe and badly bruised her knee. She was taken to the hospital where doctor gave her ATS injection and painkillers. Based on the above information, answer the following questions.
    (i) Select the correct statement.

    (a) Priya has developed natural active immunity against chicken pox. (b) Priya has developed artificial active immunity against DPT.
    (c) Priyas friend has developed artificial passive immunity against tetanus. (d) All of these

    (ii) Which of the following do you think is an example of natural passive immunity?

    (a) Administration of AGS (anti gas gangrene serum) in a person (b) Transfer of IgA antibodies from mother to baby through mother's milk
    (c) A person recovered from viral infection (d) A child vaccinated for polio

    (iii) Which of the following is true for active immunity?

    (a) It provides immediate relief. (b) It is temporary, not long lasting.
    (c) It has no side effects (d) None of these

    (iv) Select the incorrect match.

    (a) Passive immunity - IgG antibodies crossing placental barrier to reach fetus (b) Active immunity - Vaccination against corona virus
    (c) Active immunity - Administration of antidiphtheria serum in patient (d) Passive immunity - Fetus having mother's milk

    (v) Assertion: A person recovered from measles develops an active immunity against this infection.
    Reason: In active immunity, person's own cells develop antibodies in response to infection.

    (a) Both assertion and reason are true and reason is the correct explanation of assertion. (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false. (d) Both assertion and reason are false.
  • 5)

    Read the following and answer any four questions from (i) to  (v) given below:
    A group of teenagers was involved in drug abuse. They used syringes and needles to inject drugs. They indulged in this habit when they became adults. Administration of drug through needles became a piece of cake for them. Raj was the most active drug abuser amongst them and used to take drugs in high profile parties. In a span of time he started losing weight and suffered persistent diarrhoea. He developed constant low grade fever and used to catch opportunistic infection. When he consulted a doctor, he got himself tested for HIV in his blood and finally diagnosed with AIDS.
    Based on the above information, answer the following questions.
    (i) Select the incorrect statement.

    (a) AIDS is a disorder of cell mediated immune system of the body. (b) AIDS is caused by Human Immunodeficiency virus.
    (c) AIDS infections were detected in India for the first time in prostitutes ofChennai, Tamil Nadu in 1986. (d) December 10 is recalled as World AIDS Day.

    (ii) How do you think Raj got AIDS infection?

    (a) Through transfusion of HIV infected blood (b) Sexual intercourse with an infected partner
    (c) Sharing towel with infected friend (d) Use of contaminated needles and syringes to inject drugs

    (iii) How AIDS can be diagnosed?

    (a) ELISA test (b) Ames test (c) Pap's test (d) Widal test

    (iv) How can AIDS be prevented?

    (a) Blood tests of blood donor before transfusion to check for the presence of AIDS virus. (b) Use of disposable needles and syringes for injecting medicines and vaccination
    (c) Having protected sex by use of condoms (d) All of these

    (v) Select the correct statement for AIDS virus.

    (a) It is rhomboid in shape with a diameter of 10-15 cm. (b) Its genome consists of ds DNA.
    (c) It consists ofreverse transcriptase enzyme. (d) Its envelope-consists oflipid bilayer and three protein coats.

CBSE 12th Standard Biology Subject Human Health and Disease Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    Your classmate complains of cough and headache to the doctor. The doctor confirms that he is suffering from pneumonia and not just common cold.
    (a) How did the doctor arrive at this conclusion?
    (b) Write the binomials of the causative organisms of pneumonia.
    (c) What is common about the transmission of the two diseases, common cold and pneumonia?

  • 2)

    Study the diagram showing the entry of HIV into the human body and the processes that are followed:

    (a) Name the human cell 'A' HIV enters into.
    (b) Mention the genetic material 'B' HIV releases into the cell.
    (c) Identify enzyme 'C'

  • 3)


    The skeletal structure of a cannabinoid molecule is given above. Answer the following questions.
    (a) What are the modes of its consumption by humans?
    (b) Name the four different forms in which cannabinoids are produced.

  • 4)

    Read the following and answer any four questions from (i) to (v) given below :
    X and Yare communicable diseases whereas Wand Z are non-communicable diseases. X is transmitted through vectors whereas Y is transmitted through droplet infection. W is caused due to a hormone deficiency whereas Z is a degenerative disease.
    Based on the above information, answer the following questions.
    (i) Identify W, X, Y and Z.

      W X Y Z
    (a) Coronary artery disease . Cholera Chikungunya Hypertension
    (b) Diabetes Malaria Rhinitis Alzheimer's disease
    (c) Arthritis AIDS Shigella Plague
    (d) Gonorrhea Diphtheria Pertussis Anthrax

    (ii) Select the correct statement.

    (a) If X is sleeping sickness then its vector is Leishmania
    (b) If Y is diphtheria then it is caused by Bacillus anthracis
    (c) If W is hypothyroidism then it is caused by deficiency of thyroxine hormone.
    (d) If Z is myocardial infarction then patient develops acute rheumatic fever, joint pain and throat infection

    (iii) If X and Y both are usual diseases then which of the following holds true?

    (a) X could be dengue caused by flavivirus and Y could be AIDS caused by HIV.
    (b) X could be.chikungunya whereas Y could be rhinitis.
    (c) X could be hepatitis whereas Y could be rabies.
    (d) X could be chicken pox caused by Varicella zoster virus whereas Y could be yellow fever caused by flavivirus.

     (iv) If X and Y both are bacterial diseases then select the correct match from the following.

    (a) X- Bubonic plague - Yersinia pestis (b) Y - Leprosy - Mycobacterium leprae
    (c) X - Whooping cough - Bordetella pertussis (d) Y - Botulism - Clostridium botulinum

    (v) Assertion: Communicable diseases could be contagious or non-contagious.
    Reason: Diseases that spread through vectors are non-contagious disease.

    (a) Both assertion and reason are true and reason is the correct explanation of assertion. (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false. (d) Both assertion and reason are false.
  • 5)

    Read the following and answer any four questions from (i) to (v) given below:
    Priya was 4 years old when she contracted chicken pox. It took her around 15 days to recover completely. Now Priya is 5 years old so her mother got her vaccinated few days back for DPT (5th dose) as per immunisation program. Recently she was playing with her friend in the park when her friend accidently fell on iron pipe and badly bruised her knee. She was taken to the hospital where doctor gave her ATS injection and painkillers. Based on the above information, answer the following questions.
    (i) Select the correct statement.

    (a) Priya has developed natural active immunity against chicken pox. (b) Priya has developed artificial active immunity against DPT.
    (c) Priyas friend has developed artificial passive immunity against tetanus. (d) All of these

    (ii) Which of the following do you think is an example of natural passive immunity?

    (a) Administration of AGS (anti gas gangrene serum) in a person (b) Transfer of IgA antibodies from mother to baby through mother's milk
    (c) A person recovered from viral infection (d) A child vaccinated for polio

    (iii) Which of the following is true for active immunity?

    (a) It provides immediate relief. (b) It is temporary, not long lasting.
    (c) It has no side effects (d) None of these

    (iv) Select the incorrect match.

    (a) Passive immunity - IgG antibodies crossing placental barrier to reach fetus (b) Active immunity - Vaccination against corona virus
    (c) Active immunity - Administration of antidiphtheria serum in patient (d) Passive immunity - Fetus having mother's milk

    (v) Assertion: A person recovered from measles develops an active immunity against this infection.
    Reason: In active immunity, person's own cells develop antibodies in response to infection.

    (a) Both assertion and reason are true and reason is the correct explanation of assertion. (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false. (d) Both assertion and reason are false.

CBSE 12th Standard Biology Subject Evolution Case Study Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)


    (a) State the hypothesis which S.L. Miller tried to prove in the laboratory with the help of the set up given above.
    (b) Name the organic compound observed by him in the liquid water after running the above experiment.
    (c) A scientist simulated a similar set up and added CH4, NH3 and water vapour at 800°C.
    Which important component is missing in his experiment?

  • 2)


    The forelimbs of four vertebrates are shown in the diagram shown above.
    (a) What type of evolution is exhibited by the similarity among these organs in those organisms?
    (b) What are such organs known as?
    (c) What do they indicate?

  • 3)

    In 1950s, there were hardly any mosquitoes in Delhi. The use of the pesticide, DDT on standing water
    killed their larvae. But, now there are mosquitoes because they have evolved DDT-resistance through the interaction of mutation and Natural selection. State in a sequences, how that could have happened.

  • 4)

    When the reptiles came down, mammals took over the earth. There were mammals in South America, which resembled some of the modern day mammals. But due to continental drift, they disappeared whereas the pouched mammals of Australia flourished and evolved into the various forms of pouched mammals that we see today.
    (a) Mention two characteristic features that were the reasons for the successful existence of mammals on earth.
    (b) Why did the continental drift affect the mammals of South America and Australia, differently.

  • 5)

    According to Hardy-Weinberg principle, the allele frequencies in a population are stable and remain constant through generations. When the frequency differs from the expected values, the difference indicates the extent (direction) of evolutionary change. Disturbance in the genetic equilibrium or Hardy-Weinberg equilibrium in a population can be interpreted as resulting in evolution.
    (a) Write the algebraic equation representing Hardy-Weinberg equilibrium.
    (b) List the five factors that affect the genetic equilibrium.

CBSE 12th Standard Biology Subject Evolution Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)


    The forelimbs of four vertebrates are shown in the diagram shown above.
    (a) What type of evolution is exhibited by the similarity among these organs in those organisms?
    (b) What are such organs known as?
    (c) What do they indicate?

  • 2)

    Fill in the blanks in the following statements, with the time period [as million years ago (mya)] of evolution of various life forms on the earth.
    (a) The first non-cellular forms of life, i.e., giant organic molecules like RNA, proteins, etc. could have originated _______________________.
    (b) About _______________ the first cellular forms of life appeared on the earth; slowly single-celled forms became multicellular forms.
    (c) By the time of _______________ invertebrates were formed.
    (d) Jawless fish probably ev-olved around _______________.
    (e) Sea weeds and a few plant species existed probably around_______________ ; the first organisms that invaded land were plants.
    (f) About _____________ fish with stout and strong fins that could move on land and go back to water were present; they were called lobefins.

  • 3)

    Read the passage and answer the questions that follow:
    (i) Fish with stout and strong fins existed about 350 mya; they could move on land and go back into water.
    (ii) Reptiles dominated the earth for about 200 million years.
    (iii) Some land reptiles went back into water and evolved into fish-like reptiles.
    (iv) The land reptiles of that period were dinosaurs; they disagpeared suddenly from the earth.
    (a) Name the fish that could move on land and go back into water. What did they evolve into?
    (b) Give an example-ofthe fish-like reptiles. Mention the time period when they were evolved.
    (c) Name the largest of the dinosaurs. When did the dinosaurs suddenly disappeared?

  • 4)

    A few stages and their respective time period in the evolutionary history of human beings are mentioned in the flow-chart given below. Answer the questions that follow, as asked.


    (a) Name the two primates.
    (b) Name two places where the fossils were discovered.
    (c) Name the ancestor.
    (d) Name the hominid.

  • 5)


    (a) Identify the respective animal to which each of the following skulls, A, Band C belongs. Which two among them resemble more closely?
    (b) Name the (I) ape-like and (ii) man-like primates that existed 15 million years ago.

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance Case Study Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)


    A DNA replication fork is shown above. Answer the following questions based on that.
    (i) Why does DNA replication occur in such small forks?
    (ii) What is a synthesis and b synthesis?
    (iii) Mention the polarity at A and B.

  • 2)


    A particular stage in the transcription of a bacterium is given above. Answer the following questions:
    (a) Name the stage in the process.
    (b) Identify A, B, C, D and E in the diagram.

  • 3)


    A hypothetical mRNA with 12 codons is shown above.
    (a) How many amino acids will be coded by this? Justify your answer.
    (b) Mention the dual functions of the codon, AUG.

  • 4)

    Read the following and answer any four questions from (i) to (v) given below:
    In prokaryotes, DNA is circular and present in the cytoplasm but in eukaryotes, DNA is linear and mainly confined to the nucleus. DNA or deoxyribonucleic acid is a long polymer of nucleotides. In 1953, the first correct double helical structure of DNA was worked out by Watson and Crick. Based on the X-ray diffraction data produced by Maurice Wilkins and Rosalind Franklin. It is composed of three components, i.e., A phosphate group, a deoxyribose sugar and a nitrogenous base. Different forms of DNA are B-DNA, Z-DNA, A-DNA, C-DNA and D-DNA.
    (i) Name the linkage present between the nitrogen base and pentose sugar in DNA.

    (a) Phosphodiester bond (b) Glycosidic bond (c) Hydrogen bond (d) None of these

    (ii) The double helix structure of DNA was proposed by

    (a) James Watson and Francis Crick (b) Earwin Chargaff (c) Federick Griffith (d) Hershey and Chase

    (iii) The double chain of B-DNA is coiled in a helical fashion. The spiral twisting of B-DNA duplex produces

    (a) right and left part (b) major and minor grooves (c) upper and lower sides (d) linear and circular part.

    (iv) Assertion: The two strands of DNA helix have uniform distance between them.
    Reason: A large sized purine always paired opposite to a small sized pyrimidine.

    (a) Both assertion and reason are true and
    reason is the correct explanation of assertion.    		 (b) Both assertion and reason are true but
    reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false. (d) Both assertion and reason are false.

     (v) Which of the following describes the structure of B-DNA?

    Polynucleotide chains Number of base pairs per complete turn of helix
    (a) Parallel 5
    (b) Anti-parallel 10
    (c) Parallel 15
    (d) Anti-parallel 20
  • 5)

    Read the following and answer any four questions from (i) to (v) given below:
    The process of translation requires transfer of genetic information from a polymer of nucleotides to synthesise a polymer of amino acids. The relationship between the sequence of amino acids in a polypeptide and nucleotide sequence of DNA or mRNA is called genetic code. George Gamow suggested that in order to code for all the 20 amino acids, code should be made up of three nucleotides.
    (i) What is a codon?

    (a) A length of DNA which codes for a particular protein (b) A part of the tRNA molecule to which a
    specific amino acid is attached.
    (c) A part of the tRNA molecule which recognises the
    triplet code on the messenger RNA.    		 (d) A part of the messenger RNA molecule that has
    a sequence of bases coding for an amino acid.

    (ii) Three consecutive bases in the DNA molecule provide the code for each amino acid in a protein molecule. What is the maximum number of different triplets that could occurs ?

    (a) 16 (b) 20 (c) 24 (d) 64

    (iii) Listed below are some amino acids and their corresponding mRNA triplets.

    Amino acid mRNA triplet
    Phenylalanine UUU
    Lysine AAG
    Arginine CGA
    Alanine GCA

    Which DNA sequence would be needed to produce the following polypeptide sequence? Alanine- Arginine- Lysine- Phenylalanine

     (a) CGT GCT TTC AAA (b) CGT GCT TTC TTT (c) CGU GCU UUC AAA (d) CGU GCU UUC TTT

    (iv) Identify the non-sense codons among the following.

     (a) AUG (b) GUG (c) UAA (d) UGG

    (v) A polypeptide is made using synthetic mRNA molecules as shown.

    Synthetic mRNA used Polypeptide produced
    UUUAAAUUUAAA Phenylalanine-lysine- phenylalanine-lysine

    What are the DNA codes for the amino acids phenylalanine and lysine?

    Phenylalanine Lysine
    (a) AAA TTT
    (b) AAA UUU
    (c) GGG CCC
    (d) TTT GGG

CBSE 12th Standard Biology Subject Molecular Basic of Inheritance Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)


    The diagram of a nucleosome is shown above.
    (i) Identify the parts labeUed a, b, c and d in it.
    (ii) Name the positively-charged and negatively charged components in it.

  • 2)


    The Central dogma of molecular biology is shown above.
    (a) Who proposed this?
    (b) Identify the processes A, Band C in the above representation.
    (c) Why is it not applicable to certain viruses?

  • 3)


    A stage in the process of transcription in a prokaryote is shown above.
    (a) Name the stage in transcription.
    (b) Identify A and B in the diagram.
    (c) Can this process be coupled to translation ? Justify your answer.

  • 4)

    Read the following and answer any four questions from (i) to (v) given below:
    In prokaryotes, DNA is circular and present in the cytoplasm but in eukaryotes, DNA is linear and mainly confined to the nucleus. DNA or deoxyribonucleic acid is a long polymer of nucleotides. In 1953, the first correct double helical structure of DNA was worked out by Watson and Crick. Based on the X-ray diffraction data produced by Maurice Wilkins and Rosalind Franklin. It is composed of three components, i.e., A phosphate group, a deoxyribose sugar and a nitrogenous base. Different forms of DNA are B-DNA, Z-DNA, A-DNA, C-DNA and D-DNA.
    (i) Name the linkage present between the nitrogen base and pentose sugar in DNA.

    (a) Phosphodiester bond (b) Glycosidic bond (c) Hydrogen bond (d) None of these

    (ii) The double helix structure of DNA was proposed by

    (a) James Watson and Francis Crick (b) Earwin Chargaff (c) Federick Griffith (d) Hershey and Chase

    (iii) The double chain of B-DNA is coiled in a helical fashion. The spiral twisting of B-DNA duplex produces

    (a) right and left part (b) major and minor grooves (c) upper and lower sides (d) linear and circular part.

    (iv) Assertion: The two strands of DNA helix have uniform distance between them.
    Reason: A large sized purine always paired opposite to a small sized pyrimidine.

    (a) Both assertion and reason are true and
    reason is the correct explanation of assertion.    		 (b) Both assertion and reason are true but
    reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false. (d) Both assertion and reason are false.

     (v) Which of the following describes the structure of B-DNA?

    Polynucleotide chains Number of base pairs per complete turn of helix
    (a) Parallel 5
    (b) Anti-parallel 10
    (c) Parallel 15
    (d) Anti-parallel 20
  • 5)

    Read the following and answer any four questions from (i) to (v) given below :
    Translation is the process of polymerisation of amino acids to form a polypeptide. The order and sequence of amino acids are defined by the sequence bases in the mRNA. The amino acids are joined by a bond called peptide bond. Ribosome is the site of protein synthesis.
    (i) Which ion is essential for association of both units of ribosome at the time of protein formation ?

    (a) Mg2+ (b) Mn2+ (c) Cl- (d) Ca2+

    (ii) During translation, how many initiation factors are required in eukaryotes for initiation reactions?

    (a) 3 (b) 6 (c) 7 (d) 9

    (iii) Which part of mRNA contains untranslated regions (UTR)?

    (a) 3' end (b) 5' end (c) Either 3' or 5' end (d) Both 5' end and 3' end

    (iv) Name the enzyme that helps in combining amino acid to its particular tRNA.

    (a) Activating enzyme (b) Amino-acyl tRNA-synthetase (c) Peptidyl transferase (d) Both (a) and (b)

    (v) From the given list, select the translation machinery.
    1. mRNA
    2. Ribosomes
    3. Amino acids
    4. tRNAs
    5. Peptidyl transferase
    6. Amino acyl tRNA synthetase
    7. Pyrophosphatase

    (a) (1), (2), (3), (4) and (6) (b) (1), (2), (3), (4) and (5) (c) (1), (2), (3), (4), (5) and (6) (d) (1), (2), (3), (4), (5), (6) and (7)

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation Case Study Questions With Solution2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    Study the pedigree chart showing the pattern of inheritance of blood group character in a family.

    (a) Give the genotypes of the parents in generation I.
    (b) State the possible genotypes of the individuals.
    (i) X in generation II.
    (ii) Y in generation III.
    (c) How does the inheritance of this blood group explain codominance?

  • 2)

    Read the following and answer any four questions from (i) to (v) given below :
    During a study of inheritance of two genes, teacher asked students to perform an experiment. The students crossed white eyed, yellow bodied female Drosophila with a red eyed, brown bodied male Drosophila (i.e., wild). They observed that progenies in F2 generation had 1.3 percent recombinants and 98.7 percent parental type combinations. The experimental cross with results is shown in the given figure.[Note: Dominant wild type alleles are represented with (+) sign in superscript.]

    (i) By conducting the given experiment, teacher can conclude that
    A. Genes for eye colour and body colour are linked
    B. Genes for eye colour and body colour show complete linkage
    C. Linked gene remain together and are inherited

    (a) A and B only (b) B only (c) A and C only (d) A, Band C

    (ii) Teacher asked to conduct an experiment on Drosophila because

    (a) the male and female flies are easily distinguishable (b) it completes its life cycle in about two weeks
    (c) a single mating could produce a large number of progeny flies (d) all of these.

    (iii) Genes white eyed and yellow bodied located very close to one another on the same chromosome tend to be transmitted together are called

    (a) allelomorphs (b) identical genes (c) linked genes (d) recessive genes

    (iv) Select the correct statement regarding the given experiment.

    (a) The physical distance between two genes determines strength of linkage
    (b) The physical distance between two genes determines frequency of crossing over
    (c) The two linked genes always segregate independently of each other
    (d) Both (a) and (b)

    (v) Assertion : When yellow bodied, white eyed Drosophila females were hybridised with brown-bodied, red eyed males; and FI progeny was intercross ed, F2 ratio deviated from 9: 3: 3: 1.
    Reason : When two genes in a dihybrid are on the same chromosome, the proportion of parental gene combinations are much higher than the non-parental type.

    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion
    (c) Assertion is true but reason is false
    (d) Both assertion and reason are false
  • 3)

    Read the following and answer any four questions from (i) to (v) given below :
    Turner's syndrome is an example of mono somy. It is formed by the union of an allosome free egg and a normal 'X' containing sperm or a normal egg and an allosome free sperm. The individual has 2n = 45 chromosomes (44 + X0) instead of 46. Such individuals are sterile females who have rudimentary ovaries, under developed breasts, small uterus, short stature, webbed neck and abnormal intelligence. They may not menstruate or ovulate. This disorder can be treated by giving female sex hormone to the women from the age of puberty to make them develop breasts and have menstruation. This makes them feel more normal.
    (i) Number of Barr body present in a female with Turner's syndrome is

    (a) 0 (b) 1 (c) 2 (d) < 2.

    (ii) Turner's syndrome is an example of

    (a) aneuploidy (b) euploidy (c) polyploidy (d) autosomal abnormality

    (iii) Turner's syndrome is a/an

    (a) autosomal recessive Mendelian disorder (b) autosomal dominant Mendelian disorder
    (c) sex linked Mendelian disorder (d) chromosomal disorder

    (iv) Which of the following statements regarding Turner's syndrome is incorrect?

    (a) It is a case of monosomy of chromosomes
    (b) The suffering individual is a sterile female having one 'X' chromosome missing in the cells
    (c) The problem is due to an extra chromosome
    (d) The individual are of short stature

    (v) Assertion : Turner's syndrome is caused due to absence of anyone of the X and Y sex chromosome.
    Reason : Individuals suffering from Turner's syndrome show masculine as well as feminine development

    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion
    (c) Assertion is true but reason is false
    (d) Both assertion and reason are false
  • 4)

    Read the following and answer any four questions from (i) to (v) given below:
    Haemophilia is a sex linked disease which is also known as bleeder's disease as the patient will continue to bleed even from a minor cut since he or she does not possess the natural phenomenon of blood clotting due to absence of anti-haemophilic globulin or factor VIII and plasma thromboplastin factor IX essential for it. As a result of continuous bleeding the patient may die of blood loss. Colour blindness is another type of sex linked trait in which the eye fails to distinguish red and green colours. Vision is however, not affected and the colour blind can, lead a normal life, reading, writing and driving (distinguishing traffic lights by their position).(i) If a haemophilic man marries a woman whose father was haemophilic and mother was normal then which of the following holds true for their progenies?

    (a) Of the total number of daughters, 50% daughters are carrier and 50% are haemophilic
    (b) All the daughters are haemophilic.
    (c) All sons are haemophilic and all daughters are normal.
    (d) All sons are normal, all daughters are carriers.

    (ii) A man whose father was colourblind and mother was normal marries a woman whose father was haemophilic and mother was normal. Which of the following is true for their progenies? [Note: Percentage is from the total number of progenies.

    (a) 25% female progenies carry the gene for both haemophilia and colourblindness
    (b) 25% male progenies carry only the gene of colourblindness
    (c) 25% female progenies carry only the gene of colourblindness.
    (d) 25% male progenies and 25% female progenies carry the gene of haemophilia

    (iii) Which of the following statements is incorrect regarding haemophilia?

    (a) It is a dominant disease (b) A single protein involved in clotting of blood is affected (c) It is recessive disease (d) It is Mendelian disorder

    (iv) Anup is having colourblindness and is married to Soni who is normal. What is the chance that their son will have the disease?

    (a) 100% (b) 50% (c) 25% (d) 0%

    (v) Refer to the given cross

    Select the correct option regarding 1, 2, 3 and 4.

    (a) 1. Colourblind carrier female
    2. Colourblind haemophilic female
    3. Normal male
    4. Haemophilic male    		 (b) 1.Colourblind people
    2.Haemophilic female
    3.Normal male
    4..Haemophilic male    		 (c) 1. Colourblind female
    2. Colourblind and haemophilic female
    3. Normal male
    4. Normal male    		 (d) 1.Colourblind carrier female
    2.Normal female
    3.Normal male
    4.Haemophilic male
  • 5)

    Read the following and answer any four questions from (i) to (v) given below:
    A relevant portion of \(\beta\)-chain of haemoglobin of a normal human is as follows

    The codon for the sixth amino acid is GAG. The sixth codon GAG mutates to GAA as a result of mutation X and into GUG as a result of mutation Y.
    (i) Which of the following is incorrect statement?

    (a) Mutation X carries no change in shape of red blood cells.
    (b) Mutation Y causes change in shape of red blood cell shape
    (c) Both mutations X and Y causes change in shape of red blood cell shape.
    (d) Both (a) and (b)

    (ii) Due to mutation Y the shape of RBCs under oxygen tension will be

    (a) biconcave disc like (b) elongated and curve (c) circular (d) spherical

    (iii) GUG is code for

    (a) valine (b) proline (c) glutamic acid (d) leucine

    (iv) Which of the following genotype shows diseased phenotype due to mutation Y?

    (a) Hbs Hbs (b) HbA Hbs (c) HbA HbA (d) Both (a) and (b)

    (v) Study the given pedigree chart for sickle-cell anaemia and select the most appropriate option for the genotypes.

    Genotypes of parents Genotypes of 1st and 3rd child in F1
    (a) HbA HbS, HbA HbA HbA HbA, HbA HbS
    (b) HbA HbS, HbA HbS HbA HbA, HbA HbA
    (c) HbA HbA, HbA HbS HbA HbA, HbS HbS
    (d) HbA Hbs, HbA Hbs HbA HbS, HbS HbS

CBSE 12th Standard Biology Subject Principles of Inheritance and Variation Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    ABO blood group character in human population exhibits four possible phenotypes and six different genotypes. Explain the different mechanisms of inheritance involved in exhibiting the possibility of four phenotypes and six genotypes.

  • 2)

    Study the pedigree chart given below showing the inheritance pattern of a human trait and answer the questions that follow:

    (a) Is the trait autosomal dominant or recessive or sex-linked? Why?
    (b) Give the genotypes of the parents in generation I and of the son in generation II.
    (c) Give the genotype of the first grand daughter.

  • 3)

    Haemophilia is a sex-linked recessive disorder in humans. The pedigree chart given below shows the inheritance pattern of haemophilia in a family. Study the inheritance pattern and answer the questions that follow:

    (a) Give the possible genotypes of the members 4 and 5 in the above chart.
    (b) A blood test shows that the member 14 is a carrier of haemophilia. The member 15 has recently married the member 14. What is the probability of their first child being haemophilic? Show it with the help of a Punnett square.

  • 4)

    Read the following and answer any four questions from (i) to (v) given below:
    A relevant portion of \(\beta\)-chain of haemoglobin of a normal human is as follows

    The codon for the sixth amino acid is GAG. The sixth codon GAG mutates to GAA as a result of mutation X and into GUG as a result of mutation Y.
    (i) Which of the following is incorrect statement?

    (a) Mutation X carries no change in shape of red blood cells.
    (b) Mutation Y causes change in shape of red blood cell shape
    (c) Both mutations X and Y causes change in shape of red blood cell shape.
    (d) Both (a) and (b)

    (ii) Due to mutation Y the shape of RBCs under oxygen tension will be

    (a) biconcave disc like (b) elongated and curve (c) circular (d) spherical

    (iii) GUG is code for

    (a) valine (b) proline (c) glutamic acid (d) leucine

    (iv) Which of the following genotype shows diseased phenotype due to mutation Y?

    (a) Hbs Hbs (b) HbA Hbs (c) HbA HbA (d) Both (a) and (b)

    (v) Study the given pedigree chart for sickle-cell anaemia and select the most appropriate option for the genotypes.

    Genotypes of parents Genotypes of 1st and 3rd child in F1
    (a) HbA HbS, HbA HbA HbA HbA, HbA HbS
    (b) HbA HbS, HbA HbS HbA HbA, HbA HbA
    (c) HbA HbA, HbA HbS HbA HbA, HbS HbS
    (d) HbA Hbs, HbA Hbs HbA HbS, HbS HbS
  • 5)

    Read the following and answer any four questions from (i) to (v) given below:
    While studying inheritance of characters, a teacher gave the example of inheritance of attached earlobe and hypertrichosis of the ear to her students. A man with attached earlobes and extensive hair on pinna married a woman having free earlobes. The couple had four children, one son with attached earlobes and hairy pinna, one son with a free earlobes and hairy pinna and two daughters with attached earlobes. One of the daughters married a man with free earlobes and sparse hair on pinna. Teacher said if this couple would have sons there would be equal chances for both having free or attached earlobes and sparse hair on pinnae.
    (i) Attached and free earlobe are respective example of

    (a) dominant and recessive traits (b) recessive and recessive traits (c) recessive and dominant traits (d) dominant and dominant traits.

    (ii) Hypertrichosis of the ear is

    (a) X linked trait (b) Y linked trait (c) autosomal dominant trait (d) autosomal recessive trait

    (iii) If a female with attached earlobe married a male homozygous for free earlobe sparse hair on pinna then what would be the chances of daughter to have attached earlobe?

    (a) 0% (b) 100% (c) 25% (d) 75%

    (iv) If a man with attached earlobe and hairy pinna married a woman with attached earlobe then what would be the chances of son to have hairy pinna?

    (a) 50% (b) 100% (c) 75% (d) 0%

    (v) A male with attached earlobe, sparse hair on pinna married a female with attached earlobe. Which of the following is correct regarding their progenies?

    (a) All sons have a free earlobe with hairy pinna.
    (b) All daughters have an attached earlobe
    (c) 50% daughters have an attached earlobe whereas 50% daughters have a free earlobe.
    (d) 50% sons have attached earlobe with hairy pinna and 50% sons have a free earlobe.

CBSE 12th Standard Biology Subject Reproductive Health Case Study Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)


    The picture shows two different contraceptive devices, used by human females.
    (a) Identify A and B.
    (b) Mention how each ofthem prevents fertilisation and conception.

  • 2)


    (a) Identify the contraceptive device shown in the picture.
    (b) What does it contain and how is it used?
    (c) How does it function as a contraceptive?

  • 3)


    The surgical method of contraception in human females is shown above.
    Answer the following questions.
    (a) Give the technical term for the process shown above.
    (b) How is the process carried out?
    (c) What is the principle behind it as a method of contraception?

  • 4)

    Read the following and answer any four questions from (i) to (v) given below:
    Population is defined as the total number of individuals of a species present in a particular area at a given time. The scientific study of human population is called demography. The rapid increase in population over a relatively short period is called population explosion. Four basic processes are involved in increase or decrease in the population size. Population shows two types of growth; exponential and logistic.
    (i) Which of the following factors are responsible for population explosion?
    A. Decrease in number of people of reproducible age
    B. Decline in infant mortality rate
    C. Increase in maternal mortality rate
    D. Rapid decline in death rate

    (a) A and B (b) Band C (c) B and D (d) A and D

    (ii) What is the shape of curve showing logistic growth?

    (a) Sigmoid (b) J-shape (c) Linear (d) Hyperbola

    (iii) What is immigration?

    (a) Number of individuals of the population who left the habitat. (b) Number of individuals that have come into the habitat.
    (c) Number of individuals of a species per unit area at given time. (d) Number of births per 1000 individuals.

    (iv) Equation of Verhulst-Pearl logistic growth is

    (a) \(\frac{d N}{d t}=r N\) (b) \(\frac{d N}{d t}=\frac{K-N}{k}\) (c) \(\frac{d N}{d t}=r N\left(\frac{K-N}{K}\right)\) (d) \(\frac{d N}{d t}=\left(1-\frac{N}{K}\right) r\)

    (v) Which of the following contributes to decrease in population?

    (a) Fertility (b) Natality (c) Social mobility (d) Emigration
  • 5)

    Read the following and answer any four questions from (i) to (v) given below:
    A woman unable to conceive after many years of regular unprotected coitus went to specialised infertility clinic. On complete examination, woman was found to be normal while male partner was diagnosed with infertility. Male partner is unable to copulate the female. Couple was advised to opt for assisted reproductive technology (ART).
    (i) Which ART could have been useful for this couple?

    (a) ZIFT (b) IUT (c) AI (d) GIFT

    (ii) In which of the following infertility issues could this technique be used?

    (a) Anovulation (b) Oligospermia (c) Low fructose content in seminal fluid (d) All of these

    (iii) Which among the following techniques is useful to conceive when there is very low sperm count?

    (a) GIFT (b) Test-tube baby (c) IUT (d) ICSI

    (iv) Assertion: Artificial insemination (AI) is intra-uterine insemination.
    Reason: In AI, sperms collected from donor are introduced into the uterus.

    (a) Both assertion and reason are true and reason is the correct explanation of assertion (b) Both assertion and reason are true but reason is not the correct explanation of assertion
    (c) Assertion is true but reason is false (d) Both assertion and reason are false

    (v) Success rate of artificial insemination technique is

    (a) 20-40% (b) 60-70% (c) 40-50% (d) 5-7%.

CBSE 12th Standard Biology Subject Reproductive Health Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)


    The picture shows two different contraceptive devices, used by human females.
    (a) Identify A and B.
    (b) Mention how each ofthem prevents fertilisation and conception.

  • 2)

    Read the following and answer any four questions from (i) to (v) given below:
    Intrauterine devices are most widely accepted methods of contraception. These are used by females and are inserted by doctor or nurses in the uterus through vagina. However these devices are not recommended for those who eventually intend to conceive.
    (i) How does CuT prevent conception?

    (a) Cu ions make uterus unsuitable for implantation (b) Cu ions make cervix hostile to the sperms
    (c) Cu ions suppress sperms motility (d) Cu ions inhibit ovulation

    (ii) Which of the following IUDs makes uterus unsuitable for implantation?

    (a) LNG-20 (b) Multiload 375 (c) Cu7 (d) Lippes loop

    (iii) Identify the correct statement for IUDs,

    (a) They slowly release synthetic progesterone in the body. (b) They increase phagocytosis of sperms within the uterus
    (c) They block entry of sperms through the cervix. (d) Both (b) and (c)

    (iv) Select the correct matched pair.

    (a) Hormone releasing IUD - LNG-20 (b) Non-medicated IUD - Progestasert (c) Copper releasing IUD - Lippes loop (d) None of these

    (v) Assertion : IUDs can cause excess menstrual bleeding and pain.
    Reason : IUD s can perforate uterus.

    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion
    (c) Assertion is true but reason is false
    (d) Both assertion and reason are false.
  • 3)

    Read the following and answer any four questions from (i) to (v) given below:
    A technique knowa as amniocentesis is used to determine fetal abnormalities. This test is based on the chromosomal pattern in amniotic fluid. However, this technique is legally banned now.

    (i) Identify X and Y in the above given figure.

      X y
    (a) Amnion Chorion
    (b) Uterine wall Placenta
    (c) Placenta Uterine wall
    (d) Uterine wall Amnion

    (ii) What is the function of Z?

    (a) Z is an amniotic fluid which prevents dessication of an embryo. (b) Z is yolk sac which functions as site of early blood cell formation
    (c) Z is amnion which takes part in placenta formation. (d) None of these

    (iii) Which of the following diseases can not be diagnosed by amniocentesis?

    (a) Down's syndrome (b) Sickle cell disease (c) Jaundice (d) Cystic fibrosis

    (iv) Assertion: Amniocentesis is legally banned for sex determination.
    Reason: Amniocentesis was being misused for aborting normal female fetus

    (a) Both assertion and reason are true and reason is the correct explanation of assertion (b) Both assertion and reason are true but reason is not the correct explanation of assertion
    (c) Assertion is true but reason is false. (d) Both assertion and reason are false.

    (v) Which of these is a non-invasive technique of detecting fetal disorder?

    (a) Fetoscopy (b) Chorionic villi sampling (c) Amniocentesis (d) Ultrasound imaging
  • 4)

    Read the following and answer any four questions from (i) to (v) given below:
    Rohan, a 13 year old school student has been diagnosed with AIDS. He often complains of fever, nausea, headache and lethargy. Doctor advised some drugs to prolong his life.
    (i) What could be the most likely mode of transmission of disease to Rohan?

    (a) Artificial insemination (b) Sexual intercourse with infected partner
    (c) From injected mother through placenta (d) Use of contaminated blade

    (ii) Name the drug prescribed for treatment of this disease.

    (a) Zidovudine (b) Taxol (c) Vinblastine (d) Both (a) and (c)

    (iii) Assertion: AIDS is an incurable STD. 
    Reason : AIDS virus attacks helper T-Lymphocytes

    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion
    (c) Assertion is true but reason is false
    (d) Both assertion and reason are false.

    (iv) AIDS cannot be diagnosed by

    (a) ELISA (b) PCR (c) Western blotting (d) VDRL

    (v) AIDS can be transmitted, by

    (a) sharing towels (b) kissing (c) sharing contaminated needles (d) all of these
  • 5)

    Read the following and answer any four questions from (i) to (v) given below:
    Oral administration of small doses of hormones is contraceptive method used by the females. They are used in the form of tablets and hence called the pills. The oral pills are two types; mini pills and combined pills.
    (i) Mini pills contain

    (a) estrogen only (b) progestin only (c) combination of progesterone estrogen (d) inhibin.

    (ii) How do hormonal pills prevent pregnancy?

    (a) By phagocytosing the sperms (b) By inhibiting ovulation (c) By preventing sperms from entering the vagina  (d) All of these

    (iii) Pill containing non-steroidal preparation, centchroman is

    (a) Mala D (b) Mala N (c) i-Pill (d) Saheli

    (iv) Which among the following is incorrect for oral contraceptives?

    (a) Oral pills alter the uterine endometrium and make it unsuitable for implantation.
    (b) Oral pills have to be taken daily for 7 days starting within first five days of menstrual cycle.
    (c) Oral pills increase the risk of intravascular clotting.
    (d) Oral pills contain either progestin alone or combination of progestogen and estrogen.

    (v) Assertion : Mala D, a combined contraceptive pill have to be taken daily without a break.
    Reason : Mala D contains synthetic progesterone and estrogen.

    (a) Both assertion and reason are true and reason is the correct explanation of assertion. (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false (d) Both assertion and reason are false

CBSE 12th Standard Biology Subject Human Reproduction Case Study Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)


    A Human Spermatozoan
    A diagrammatic sketch of a human sperm is given. Identify the parts labelled A, Band C and mention their respective functions.

  • 2)


    Read the graph given above and answer the following questions:
    (a) Identify the ovarian hormones X and Y and name their respective sources in the ovary.
    (b) Why does the hormone X peak before the hormone Y?

  • 3)

    Study the flow chart given below and answer the questions that follow:

    (a) Name the hormone(s) (in full form) involved in each of the stages, 
    (b) Specify the structure in the ovary that is the source of the hormone at stage 

  • 4)

    Read the following and answer any four questions from (i) to (v) given below:
    Human male reproductive system comprises of a pair of testes, primary sex organs associated with formation of gametes and production of sex hormone. Study the given figure of human male reproductive system and answer the following questions.

    (i) Which of the following is correct for labelled part P?

    (a) P is rete testis which transports sperms to outside. (b) P is epididymis which secretes fluid that nourish the sperms (c) P is epididymis that carry sperms and secretion of seminal vesicles (d) P is rete testis which lies along inner side of each testis and stores the sperms

    (ii) Identify the correctly matched pair.

    (a) Q - Vasa efferentia (b) R - Ejaculatory duct (c) S - Seminal vesicle (d) T - Cowper's gland

    (iii) Which statement is incorrect for Q?

    (a) It carries spermatozoa from epididymis to ejaculatory duct (b) Q are only 2 in number. (c) It arises from rete testis. (d) It constitutes male sex accessory duct

    (iv) Which structure passes through the prostate gland and carries sperms and secretion of seminal vesicle?

    (a) P (b) T (c) S (d) R

    (v) Assertion: Mucus present in secretion of bulbourethral gland decreases the number of sperms damaged during ejaculation
    Reason: Mucus lubricates the end of penis and lining of the urethra.
    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false.
    (d) Both assertion and reason are false .

  • 5)

    Read the following and answer any four questions from (i) to (v) given below:
    The first menstruation is called menarche, that usually occurs between 12 and 15 years. In human females, menstruation is repeated at an average interval of about 28129 days and is called menstrual cycle. It is regulated by certain hormones, as pituitary gland is stimulated by releasing factors produced in the hypothalamus. The hormones produced by pituitary gland influence the ovaries. The hormones secreted by the ovaries affect the walls of the uterus.
    (i) The breakdown of endometrium is characteristic of

    (a) proliferative phase (b) luteal phase (c) ovulatory phase (d) menstrual phase

    (ii) Which days of the menstrual cycle marks the proliferative phase?

    (a) 1-5 (b) 15-28 (c) 6-13 (d) 10-14

    (iii) Which of the following occurs during secretory phase?

    (a) Empty Graafian follicle changes into corpus luteum. (b) Primary follicle changes' into Graafian follicle. (c) Endometrium rebuilds and estrogen secretion increases (d) LH surge inducing release of an ovum.

    (iv) Identify the hormones that attain peak level during ovulatory phase

    (a) FSH (b) Progesterone (c) LH (d) Both (a) and (c)

    (v) Withdrawal of which hormone causes degeneration of corpus luteum?

    (a) FSH (b) LH (c) Progesterone (d) Estrogen

CBSE 12th Standard Biology Subject Human Reproduction Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    Study the following flow chart and answer the questions that follow:

  • 2)


    With reference to the above schematic diagram of (a) Spermatogenesis and (b) Oogenesis, answer the following questions.
    (a) About 300 million spermatozoa may be present in a human male ejaculate at one time. Calculate how many primary spermatocytes will be involved to produce this number of spermatozoa .
    (b) How many spermatids will be formed?
    (c) How many chromatids are found during Oogenesis in
    (i) Primary oocyte and
    (ii) First polar body in a human female?

  • 3)


    The events in a menstrual cycle are represented above. Answer the following questions based on that.
    (a) Why is the phase between 5th and 15th day of menstrual cycle, called
    (i) proliferative phase?
    (ii) follicular phase?
    (b) Mention the ovarian events during the luteal phase.

  • 4)

    Study the flow chart given below and answer the questions that follow:

    (a) Name the hormone(s) (in full form) involved in each of the stages, 
    (b) Specify the structure in the ovary that is the source of the hormone at stage 

  • 5)

    Read the following and answer any four questions from (i) to (v) given below:
    Human male reproductive system comprises of a pair of testes, primary sex organs associated with formation of gametes and production of sex hormone. Study the given figure of human male reproductive system and answer the following questions.

    (i) Which of the following is correct for labelled part P?

    (a) P is rete testis which transports sperms to outside. (b) P is epididymis which secretes fluid that nourish the sperms (c) P is epididymis that carry sperms and secretion of seminal vesicles (d) P is rete testis which lies along inner side of each testis and stores the sperms

    (ii) Identify the correctly matched pair.

    (a) Q - Vasa efferentia (b) R - Ejaculatory duct (c) S - Seminal vesicle (d) T - Cowper's gland

    (iii) Which statement is incorrect for Q?

    (a) It carries spermatozoa from epididymis to ejaculatory duct (b) Q are only 2 in number. (c) It arises from rete testis. (d) It constitutes male sex accessory duct

    (iv) Which structure passes through the prostate gland and carries sperms and secretion of seminal vesicle?

    (a) P (b) T (c) S (d) R

    (v) Assertion: Mucus present in secretion of bulbourethral gland decreases the number of sperms damaged during ejaculation
    Reason: Mucus lubricates the end of penis and lining of the urethra.
    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false.
    (d) Both assertion and reason are false .

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants Case Study Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    Read the following and answer any four questions from (i) to (v) given below:
    Cross pollination is the transfer-of pollen grains from the anther of a one flower to the stigma of a genetically different flower. It is performed with the help of an external agency which may be abiotic (e.g., wind, water) or biotic (e.g., insects, birds, bats, snails). The diagram shows the carpel of an insect pollinated flower.

    (i) What is the most likely reason for non germination of pollen grain Z?
    (a) Pollen grains X and Y were brought to the stigma earlier, therefore, their germination inhibited the germination of pollen grain Z.
    (b) Pollen grain Z was brought to the flower by wind, while pollen grains X and Y were broughtto the flower by insect
    (c) Pollen grain Z lacks protrusions that allow it to adhere properly onto the stigma surface
    (d) Pollen grain Z comes from a flower of an incompatible species
    (ii) Which of the following best describes the function of the pollen tube?
    (a) It acts as a conduit to transport male gametes from the anther to the ovule
    (b) It acts as a conduit to transport male gametes from the stigma to the ovule.
    (c) It contains key nutrients that serve to nourish the newly-formed zygote
    (d) It digests the tissues of the stigma, style and ovary.
    (iii) Pollination of a flower in which the pollen is carried by an insect is called

    (a) anemophily (b) ornithophily (c) entomophily (d) malacophily.

    (iv) Refer to the given characteristics of some flowers:

    A. The stamens hang out of the flower, exposing the anthers to the wind. B. The pollen grains are tiny and light C. The flower has a sweet scent. D. The flower petals are brightly coloured.

    How many of the above characteristics are of insect-pollinated flower?

    (a) One (b) Two (c) Three (d) Four

    (v) Pollenkitt is generally found in

    (a) anemophilous flowers (b) entomophilous flowers (c) ornithophilous flowers (d) malacophilous flowers.
  • 2)

    Read the following and answer any four questions from (i) to (v) given below:
    In angiosperms, the pollen grains are being transferred from the anther to the stigma and is termed pollination. This phenomenon was first discovered by Camerarius (1694) in the end of seventeenth century. Pollen grains are immobile. They cannot reach the stigma by themselves. An external agent is required for this. The pollination is mainly of two types-self pollination and cross pollination.
    The diagram given below shows two plants of the same species showing different types of pollination.

    (i) What is transferred between the plants in the process indicated by arrow P?

    (a) Ova (b) Pollen (c) Nutrients (d) Seeds

    (ii) Which of the following statements is correct regarding processes P,Q and R?
    (a) Processes P, Q and R introduce genetic variability in the offspring of sexually reproducing plants X andY.
    (b) Wind serves as agent for process Q if plants X and Y belong to Genus Salvia.
    (c) Flowers of plants X and Y need to produce odour and nectar for completion of processes P and Q if they-are entomophilous.
    (d) If plants X and Y belong to Genus Cannabis, then their flowers need to produce sticky and heavy pollens in very small amount for accomplishment of process Q.

    (iii) Identify the processes P,Q and R.

                     P              Q             R
    (a) Geitonogamy Xenogamy Autogamy
    (b) Allogamy Chasmogamy Cleistogamy
    (c) Autogamy Geitonogamy Xenogamy
    (d) Geitonogamy Allogamy Autogamy

    (iv) In Catharanthus, the growth of style brings the stigma in contact of ripe anthers present on the mouth of corolla tube. This is an example of

    (a) homogamy (b) cleistogamy (c) geitonogamy (d) xenogamy.

    (v) Which of the given processes represents a type of pollination that would result in greater adaptability of the particular species to potential environmental changes?

    (a) P (b) Q (c) R (d) All of these
  • 3)

    Read the following and answer any four questions from (i) to (v) given below:
    The endosperm makes the main source of food for the embryo. Generally the endosperm nucleus divides after the division of the oospore, but in several cases the endosperm is formed to a great extent even before the first division of the oospore. There are three general types of endosperm formation: (a) nuclear type, (b) cellular type and (c) helobial type. The endosperm is usually triploid but haploid endosperm is also found. Endosperm may either be completely consumed by the developing embryo before seed maturation or it may persist in the mature seed.
    (i) Haploid endosperm is found in

    (a) Pinus (b) cauliflower (c) sunflower (d) pea

    (ii) Persistent endosperm is found in
    P. Pea  Q. Castor  R. Bean  S. Coconut    T. Groundnut 

    (a) Q and S (b) P and T (c) R, S and T (d) P, S and T

    (iii) Milk of tender coconut represents.(i) and the surrounding white coconut meal represents (ii).

                             (I)                            (ii)
    (a) cellular endosperm free-nuclear endosperm
    (b) free-nuclear endosperm cellular endosperm
    (c) helobial endosperm cellular endosperm
    (d) free-nuclear endosperm helobial endosperm

    (iv) If an endosperm cell of a gymnosperm contains 12 chromosomes, the number of chromosomes in each cell of the root will be

    a) 4 (b) 24 (c) 16 (d) 6

    (v) In angiosperms, normally after fertilisation

    (a) the zygote divides earlier than the primary endosperm nucleus (b) the primary endosperm nucleus divides earlier than the zygote (c) both the zygote and primary endosperm nucleus divide simultaneously (d) both the zygote and primary endosperm nucleus undergo a resting period.
  • 4)

    Read the following and answer any four questions from (i) to (v) given below:
    Embryo develops at the micropylar end of the embryo sac where the zygote is situated. Most zygotes divided only after certain amount of endosperm is formed. The early stages of embryo development are similar in both monocotyledons and dicotyledons. The zygote gives rise to the proembryo and subsequently to the globular heart-shaped and mature embryo. A typical dicotyledonous embryo consists of an embryonal axis and two cotyledons. Embryo of monocotyledons possess only one cotyledon.
    (i) True embryo develops as a result of fusion of

    (a) two polar nuclei of embryo sac (b) an egg cell and a male gamete  (c) synergid and male gamete (d) a male gamete and antipodals

    (ii) Refer to the given diagram of the embryo of an angiospermous plant with parts labelled P, Q and R. Select the correct statement(s) regarding this.

    (i) Part 'P' supplies nutrition to the developing embryo.
    (ii) Part 'Q' is the protective sheath of radicle and root cap.
    (iii) Part 'R' is the protective sheath of shoot apex and leaf primordia.
    (iv) The embryo shown in the diagram is present in members of Family Poaceae.

    (a) (iv) only (b) (ii) and (iii) only (c) (i) and (iv) only (d) (i), (ii), (iii) and (iv)

    (iii) Which of the given statements are true?
    (i) During the development of a dicot embryo, heart-shaped embryo is followed by globular embryo.
    (ii) The part of embryonal axis above-the level of cotyledons is epicotyl, while the part below the level of cotyledons is hypocotyl.
    (iii) Monocot seeds possess a single cotyledon represented by scutellum.

    (a) (i) and (ii) (b) (ii) and (iii) (c) (i) and (iii) (d) (i), (ii) and (iii)

    (iv) Consider the following parts of an embryonal axis of a dicot seed.
    (i) Hypocotyl     (ii) Epicotyl     (iii) Radicle    (iv) Plumule
    In which of the following the above parts are correctly arranged from top to base?

    (a) (iii) \(\to \) (i) \(\to \) (ii) \(\to \) (iv). (b) (ii) \(\to \) (i) \(\to \) (iii) \(\to \) (iv) (c) (iv)\(\to \)  (ii) \(\to \) (i) \(\to \) (iii) (d) (iii) \(\to \) (iv) \(\to \) (ii) \(\to \) (i)

    (v) In grass family, the cotyledon is called

    (a) epiblast (b) plumule (c) scutellum (d) perisperm
  • 5)

    Read the following and answer any four questions from (v) to (v) given below:
    A typical angiospermic ovule is a small structure attached to the placenta by means of a stalk called funicle. The body of the ovule fuses with funicle in the region called hilum. Each ovule has one or two protective envelopes called integuments. Integuments encircle the nucellus except at the tip where a small opening called the micropyle is formed. Mature ovules are classified on the basis of funiculus. It can be orthotropous, anatropous, hemitropous, campylotropous, etc.
    (i) The body of the ovule consists of a mass of parenchymatous cells called

    (a) integuments (b) nucellus (c) hilum (d) funiculus

    (ii) Refer to the given figure and select the correct statement regarding it.

    (a) This type of ovule is found in cactus.
    (b) The micropyle comes to lie close to the funiculus due to unilateral growth of ovule.
    (c) It is most common type of ovule found in the members of Chenopodiaceae
    (d) It is half inverted ovule.

    (iii) Identify the parts labelled as A, B, Cand D in the given figure and select the correct option

    A B C D
    (a) Chalaza Female gametophyte Embryo sac Micropyle
    (b) Chalaza Nucellus Embryo sac Micropyle
    (c) Micropyle Egg Embryo sac Chalaza
    (d) Micropyle Nucellus Embryo sac Chalaza

    (iv) Mature ovules are classified on the basis of funiculus. If micropyle lie close to the funiculus, the ovule is termed as

    (a) orthotropous (b) anatropous (c) hemitropous (d) campylotropous

    (v) In Asphodelus, ovule is

    (a) unitegmic (b) tritegmic (c) bitegmic (d) ategmic

CBSE 12th Standard Biology Subject Sexual Reproduction in Flowering Plants Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)


    The diagram of an anatropous ovule is presented above.
    (a) Give the technical term for ovule.
    (b) Identify and name the part that
    (i) attaches the ovule to the placenta
    (ii) remains as perisperm in some seeds.
    (iii) forms the testa of seed.
    (iv) represents the basal part of the ovule.
    (v) represents the female gametophyte.

  • 2)


    A fully developed embryo sac
    A fully-developed and mature embryo sac is shown above.
    (a) Name the cell from which it has developed.
    (b) What is the ploidy level of its nuclei?
    (c) What is filiform apparatus? Mention its significance.

  • 3)


    Identify the types of flowers A and B on the Commelina plant shown above.
    (b) Mention the type(s) of pollination that can occur in each of them.

  • 4)

    Read the following and answer any four questions from (i) to (v) given below:
    Apomixis is a mode of reproduction which does not involve formation of zygote through gametic fusion. In plants, apomixis commonly mimics sexual reproduction but produces seeds without fertilisation. There are several methods of apomictic development in seeds. The two common ones are recurrent agamospermy and adventive embryony.
    (i) Apomixis is a type of reproduction in plants in which
    (a) fertilisation does not take place
    (b) male nucleus takes part in fertilisation
    (c) pollen fusion takes place
    (d) generative nucleus takes part in fertilisation

    (ii) Which of the following statements is incorrect regarding recurrent agamospermy?
    (a) It is the formation of seed that has an embryo formed without meiosis and syngamy
    (b) All the cells of embryo sac are diploid.
    (c) An embryo develops directly from a diploid cell other than egg like that of nucleus and integument
    (d) None of these
    (iii) Adventive embryony is found in

    (a) Citrus (b) Opuntia (c) Apple (d) Both (a) and (b).

    (iv) Formation of embryo directly from diploid egg without fertilisation is called

    (a) apospory (b) diplospory (c) polyembryony (d) diploid parthenogenesis

    (v) If any somatic cell of sporophyte produces gametophyte without reduction division, it is called

    (a) parthenogenesis (b) apogamy (c) apospory (d) amphimixis
  • 5)

    Read the following and answer any four questions from (v) to (v) given below:
    A typical angiospermic ovule is a small structure attached to the placenta by means of a stalk called funicle. The body of the ovule fuses with funicle in the region called hilum. Each ovule has one or two protective envelopes called integuments. Integuments encircle the nucellus except at the tip where a small opening called the micropyle is formed. Mature ovules are classified on the basis of funiculus. It can be orthotropous, anatropous, hemitropous, campylotropous, etc.
    (i) The body of the ovule consists of a mass of parenchymatous cells called

    (a) integuments (b) nucellus (c) hilum (d) funiculus

    (ii) Refer to the given figure and select the correct statement regarding it.

    (a) This type of ovule is found in cactus.
    (b) The micropyle comes to lie close to the funiculus due to unilateral growth of ovule.
    (c) It is most common type of ovule found in the members of Chenopodiaceae
    (d) It is half inverted ovule.

    (iii) Identify the parts labelled as A, B, Cand D in the given figure and select the correct option

    A B C D
    (a) Chalaza Female gametophyte Embryo sac Micropyle
    (b) Chalaza Nucellus Embryo sac Micropyle
    (c) Micropyle Egg Embryo sac Chalaza
    (d) Micropyle Nucellus Embryo sac Chalaza

    (iv) Mature ovules are classified on the basis of funiculus. If micropyle lie close to the funiculus, the ovule is termed as

    (a) orthotropous (b) anatropous (c) hemitropous (d) campylotropous

    (v) In Asphodelus, ovule is

    (a) unitegmic (b) tritegmic (c) bitegmic (d) ategmic

CBSE 12th Standard Biology Subject Reproduction in Organisms Case Study Questions With Solution 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)


    The stages in the binary fission of Amoeba are shown above.
    (a) Arrange the stages in their proper natural sequence in binary fission.
    (b) How does this differ from the process of sporulation employed by Amoeba?

  • 2)


    Identify the plant and the vegetative propagule ofA, Band C.

  • 3)


    (a) Identify the asexual reproductive units and the respective organism (A and B) producing each of them, as shown in the diagram given.
    (b) Write two differences between these two reproductive units.

  • 4)


    (a) State the type of gametes sbown in the diagram.
    (b) Identify the process taking place and the resultant structure.
    (c) Name an organism that reproduces in tbis manner.

  • 5)


    The reproductive organs of
    (i) Chara, an alga and
    (ii) earthworm, an animal are sbown in tbe above diagram.
    (a) Identify and name tbe male and female reproductive organs of tbese two organisms.
    (b) What technical term is given to
    (i) the plant, Chara and
    (ii) the animal, earthworm, respectively, that possess both male and female reproductive organs in the same individual?

CBSE 12th Standard Biology Subject Reproduction in Organisms Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)


    The stages in the binary fission of Amoeba are shown above.
    (a) Arrange the stages in their proper natural sequence in binary fission.
    (b) How does this differ from the process of sporulation employed by Amoeba?

  • 2)


    (a) Name the organism and the mode of reproduction shown in the diagram given above.
    (b) Write two differences between budding and the binary fission in Amoeba.

  • 3)


    Identify the plant and the vegetative propagule ofA, Band C.

  • 4)

    Many of you would be knowing that a particular plant species flowered during September - October, 2006. Its mass flowering transformed large tracts of the hilly areas of Kerala, Karnataka, and Tamil Nadu into blue stretches and attracted a large number of tourists.
    (a) Write the scientific name of the plant whose flowering was responsible for this.
    (b) What is unique about its flowering phenomenon?
    (c) Name another plant and its unusual flowering phenomenon.

  • 5)


    The reproductive organs of
    (i) Chara, an alga and
    (ii) earthworm, an animal are sbown in tbe above diagram.
    (a) Identify and name tbe male and female reproductive organs of tbese two organisms.
    (b) What technical term is given to
    (i) the plant, Chara and
    (ii) the animal, earthworm, respectively, that possess both male and female reproductive organs in the same individual?

CBSE 12th Standard Biology Subject Case Study Questions 2021 - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    Read the following and answer any four questions from (i) to (v) given below:
    Non-native or alien species are often introduced in advertently for their economic and other uses. They often become invasive and drive away-the local species. Exotic species have proved harmful to both aquatic and terrestrial ecosystems. For example, water hyacinth (Eichhornia crassipes) was introduced in Indian waters to reduce pollution. It was clogged water bodies including wetlands at many places resulting in death of several aquatic plants and animals.
    (i) Island water ecosystem are the most vulnerable due to

    (a) small size  (b) small number of species  (c) increases reproductive capacity  (d) both (a) and (b).

    (ii) Which of the following is not an alien species?

    (a) Lantana camara  (b) Periplaneta americana  (c) Nile Perch  (d) Yucca moth

    (iii) Second major cause of species extinction is

    (a) habitat loss and fragmentation  (b) over exploitation  (c) alien species invasion  (d) co-extinction.

    (iv) Assertion: Eichhornia crassipes drains off oxygen from water and can be seen growing in standing water.
    Reason: Eichhornia crassipes is an indigenous species of India.

    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false.
    (d) Both assertion and reason are false.

    (v) The population of species P in a certain community was constant until a population species Q from a distant land was subsequently introduced into that community. The interaction between the two populations is reflected in the graph below.

    What could be the possible reason for the decrease in the population of species P over a number of days?

    (a) Species Q is a predator of species P.
    (b) Species Q.is a prey species which wiped out the population of species P.
    (c) Species P and Q compete for space but feeds on different food.
    (d) None of these
  • 2)

    Read the following and answer any four questions from (i) to (v) given below:
    Golden rice was engineered from normal rice by Potrykus and Beyer in the 1990s. The typical golden colour is due to the production of \(\beta\) carotene a precursor of vitamin - A. Golden rice differs from its parental strain by the addition of three \(\beta\) carotene genes. These included two genes from daffodil plant and third from a bacterium. The incorporation of these genes allows the rice plant to modify certain metabolic pathways in its cells to produce \(\beta\)-carotene.
    (i) Due to genetic modification golden rice plants produce and store \(\beta\) - carotene in

    (a) stem  (b) seed  (c) leaves  (d) all of these

    (ii) Transfer of genes to produce golden rice is achieved by

    (a) Agrobacterium  (b) pBR322  (c) \(\lambda \text { -phage }\)  (d) gene gun

    (iii) In golden rice two genes were taken from

    (a) Narcissus sp.  (b) Erwinia  (c) Coryza sativa  (d) none of these

    (iv) Golden rice is helpful to fight against disease caused by the deficiency of

    (a) Vitamin Bl2  (b) Vitamin C  (c) Vitamin A  (d) Vitamin D.

    (v) Golden rice was genetically engineered by

    (a) Fire and Mello  (b) Potrykus and Beyer  (c) Banting and Best  (d) Kohler and Milstein
  • 3)

    Read the following and answer any four questions from (i) to (v) given below:
    Ecosystem diversity is the variety of forms in the ecosystem due to diversity of niches, trophic levels and ecological processes like nutrient recycling, food webs, energy flow, etc. Study the given figure.

    (i) Identify different types of diversity denoted by 1, 2 and 3 in the given figure.

       1 2 3
    (a)    Alpha diversity  Beta diversity  Gamma diversity
    (b)  Gamma diversity  Alpha diversity  Beta diversity
    (c)  Gamma diversity  Beta diversity  Alpha diversity
    (d)  Beta diversity  Alpha diversity  Gamma diversity

    (ii) Alpha diversity is biodiversity present

    (a) within community  (b) between communities  (c) in ranges of communities  (d) none of these.

    (iii) Diversity represented by diversity of habitats over a total landscape area is

    (a) α - diversity  (b) γ-diversity  (c) β -diversity  (d) δ - diversity

    (iv) Concept of three types of ecological diversity was given by

    (a) Elton  (b) Odum  (c) Edward Wilson  (d) Whittaker.

    (v) The diversity of organisms sharing the same habitat or community is termed as

    (a) alpha diversity  (b) beta diversity  (c) gamma diversity  (d) delta diversity.
  • 4)

    Read the following and answer any four questions from (i) to (v) given below:
    Biosphere reserves are multipurpose protected areas which are meant for preserving genetic diversity in representative ecosystems of various natural biomes and unique biological communities by protecting wild populations, traditional life style of tribals and domesticated plant/animal genetic resources. Each biosphere reserve has three zones-core, buffer and transition zone.
    (i) Which of the following is similar to biosphere reserve in terms of conservation?

    (a) Gene banks  (b) Offsite collection  (c) Orchards  (d) Hotspots

    (ii) Refer to the given figure representing different zones of a biosphere reserve and select the correct option regarding it.

    (a) A-Limited human activity is allowed such as for research and education.
    (b) B-An active co-operation occurs between reserve management and local people for activities like cropping, settlements, etc.
    (c) C-No human activity is allowed.
    (d) None of these

    (iii) Refer to the given diagrammatic representation of a biosphere reserve. Select the incorrect statement regarding X, Y and Z.

    (i) X is devoted to strict protection of wildlife and no human activity is allowed in this zone.
    (ii) In Y, only limited human activity (compatible with conservation) is allowed.
    (iii) In Z, commercial exploitation of natural resources is allowed.
    (iv) Tourism is allowed in Z zone only.
    (v) Zone Y helps to maintain the lifestyle of the tribal people living in the area.

    (a) (iii), (iv) and (v) only  (b) (ii), (iii) and (v) only  (c) (i), (iii) and (iv) only  (d) (ii), (iii) and (iv) only

    (iv) Biosphere reserves differ from national parks and wildlife sanctuaries because in the former.

    (a) human beings are not allowed to enter
    (b) people are an integral part of the system
    (c) plants are paid greater attention than the animals
    (d) living organisms are brought from all over the world and preserved for posterity.

    (v) MAB Programme means

    (a) Man and biosphere programme
    (b) Man and biodiversity conservation programme
    (c) Manually aided biosphere conservation programme
    (d) none of these.
  • 5)

    Read the following and answer any four questions from (i) to (v) given below:
    Microorganisms include bacteria, viruses, fungi and protozoa. In our mind, we presume, most of the time, that microbes are always harmful. Microbes are, of course, the causal agents of many infections diseases of plants and animals including humans but they also have lots of beneficial role. Lactic acid bacteria (LAB) are one of this kind of useful group. These are Gram positive, non-sporulating, either rod shaped or spherical bacteria. They produce lactic acid in milk products as major metabolic end product of carbohydrate fermentation. LAB are considered as natural fermentors. Lactobacillus is a common LAB which converts lactose sugar of milk into lactic acid, that causes coagulation and partial digestion of milk protein casein. Milk is then changed into curd, yoghurt and cheese. Lactobacillus is also used in probiotics which have potentially beneficial effect on gut ecosystem of humans. Some other pro biotic strain used belong to the Genus Bifidobacterium.
    (i) Which of the following is not considered as microorganisms?

    (a) Bacteriophage (b) Streptococcus (c) Porphyra (d) Staphylococcus

    (ii) Select the incorrect option regarding the characteristics oflactic acid bacteria.

    (a) They are rod-shaped or spherical (b) They are Gram positive (c) They take part in carbohydrate fermentation. (d) They are acid intolerant

    (iii) Which of the following is not a lactic acid producing bacteria?

    (a) Streptococcus (b) Lactococcus (c) Saccharomyces (d) Enterococcus

    (iv) Probiotics are

    (a) gut friendly live bacteria (b) acid balancing alternated bacteria (c) beneficial amount of dead bacteria (d) Gram negative attenuated bacteria

    (v) Assertion: Lactobacillus bacteria do not retain crystal violet stain while staining.
    Reason: Lactobacillus have a very thin layer of peptidoglycan layer in their cell wall.
    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false.
    (d) Both assertion and reason are false.

CBSE 12th Standard Biology Subject Case Study Questions With Solution 2021 Part - II - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)

    Read the following and answer any four questions from (i) to (v) given below:
    A woman unable to conceive after many years of regular unprotected coitus went to specialised infertility clinic. On complete examination, woman was found to be normal while male partner was diagnosed with infertility. Male partner is unable to copulate the female. Couple was advised to opt for assisted reproductive technology (ART).
    (i) Which ART could have been useful for this couple?

    (a) ZIFT (b) IUT (c) AI (d) GIFT

    (ii) In which of the following infertility issues could this technique be used?

    (a) Anovulation (b) Oligospermia (c) Low fructose content in seminal fluid (d) All of these

    (iii) Which among the following techniques is useful to conceive when there is very low sperm count?

    (a) GIFT (b) Test-tube baby (c) IUT (d) ICSI

    (iv) Assertion: Artificial insemination (AI) is intra-uterine insemination.
    Reason: In AI, sperms collected from donor are introduced into the uterus.

    (a) Both assertion and reason are true and reason is the correct explanation of assertion (b) Both assertion and reason are true but reason is not the correct explanation of assertion
    (c) Assertion is true but reason is false (d) Both assertion and reason are false

    (v) Success rate of artificial insemination technique is

    (a) 20-40% (b) 60-70% (c) 40-50% (d) 5-7%.
  • 2)

    Read the following and answer any four questions from (i) to (v) given below :
    Riya studies in II standard in a government schooL She belongs to a backward family and her parents did not get her properly vaccinated according to immunisation programme. Once while playing in school playground she fell down due to weakness and developed high fever, headache and stiffness in her neck. Identify the illness she could be suffering from and answer the following questions.
    (i) The microbe responsible for Riyas illness could be

    (a) Vibrio cholerae (b) Enterovirus (c) Plasmodium (d) Mycobacterium.

    (ii) Which vaccine, if administered earlier, would have saved Riya from the illness she unfortunately contracted?

    (a) Salk vaccine (b) MMR vaccine (c) BCG vaccine (d) Varicella vaccine

    (iii) The disease that Riya has contracted spreads through

    (a) bite of an infected mosquito (b) bite of an infected dog (c) faecal oral route (d) direct contact with the infected person.

    (iv) Riya can spread her illness to other children through

    (a) her faeces (b) direct contact (c) coughing and sneezing in open (d) vectors.

    (v) Assertion: Polio produces inflammation of the nervous system.
    Reason: Stiffness of the neck, paralysis of particular skeletal muscle is an important symptom of polio.

    (a) Both assertion and reason are true and reason is the correct explanation of  assertion. (b) Both assertion and reason are true but reason is not the correct explanation of  assertion.
    (c) Assertion is true but reason is false (d) Both assertion and reason are false.
  • 3)

    Read the following and answer any four questions from (i) to (v) given below:
    The given graphs show fluctuations in blood sugar of person X and Y during a 24 hour time period.

    Based on the above information, answer the following questions.
    (i) Which of the following holds true for person X?

    (a) Person X is suffering from type I diabetes. (b) Person X shows severe insulin deficiency and beta cell depletion.
    (c) Person X is normal and shows good control of blood sugar level. (d) Person X is subjected to excessive urination and abnormal thrust.

    (ii) The given graph indicates that person Y is suffering from

    (a) diabetes (b) hypertension (c) atherosclerosis  (d) rheumatic heart disease.

    (iii) Which of the following conditions are common in person Y?

    (a) Excretion of glucose in urine and excessive urination (b) Polydipsia and mild beta cell depletion
    (c) Progressive erosion of articular cartilage at synovial joint (d) Both (a) and (b)

    (iv) A person suffering from diabetes mellitus becomes weak because

    (a) the cells are unable to utilise glucose and other carbohydrates for energy production (b) degradation of fat increases production of toxic ketone bodies
    (c) cells utilize proteins for obtaining energy (d) all of these.

    (v) Assertion: Type I diabetes involves failure of insulin to facilitate the movement of glucose into cells.
    Reason: Type II diabetes is caused by failure of beta cells to produce adequate amount of insulin due to beta cell depletion.

    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false.
    (d) Both assertion and reason are false.
  • 4)

    Read the following and answer any four questions from (i) to (v) given below :
    Turner's syndrome is an example of mono somy. It is formed by the union of an allosome free egg and a normal 'X' containing sperm or a normal egg and an allosome free sperm. The individual has 2n = 45 chromosomes (44 + X0) instead of 46. Such individuals are sterile females who have rudimentary ovaries, under developed breasts, small uterus, short stature, webbed neck and abnormal intelligence. They may not menstruate or ovulate. This disorder can be treated by giving female sex hormone to the women from the age of puberty to make them develop breasts and have menstruation. This makes them feel more normal.
    (i) Number of Barr body present in a female with Turner's syndrome is

    (a) 0 (b) 1 (c) 2 (d) < 2.

    (ii) Turner's syndrome is an example of

    (a) aneuploidy (b) euploidy (c) polyploidy (d) autosomal abnormality

    (iii) Turner's syndrome is a/an

    (a) autosomal recessive Mendelian disorder (b) autosomal dominant Mendelian disorder
    (c) sex linked Mendelian disorder (d) chromosomal disorder

    (iv) Which of the following statements regarding Turner's syndrome is incorrect?

    (a) It is a case of monosomy of chromosomes
    (b) The suffering individual is a sterile female having one 'X' chromosome missing in the cells
    (c) The problem is due to an extra chromosome
    (d) The individual are of short stature

    (v) Assertion : Turner's syndrome is caused due to absence of anyone of the X and Y sex chromosome.
    Reason : Individuals suffering from Turner's syndrome show masculine as well as feminine development

    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion
    (c) Assertion is true but reason is false
    (d) Both assertion and reason are false
  • 5)

    Read the following and answer any four questions from (i) to (v) given below:
    Aditya went to his hometown located in countryside along with his parents during his summer vacations. His grand parents' house is surrounded by farmland from all sides. Lots of crops were growing nearby and Aditya was very excited to visit the crop fields. He seeked permission from his mother to play in farmland along with his friends and then went to play in the fields. On returning back he had running nose, watering eyes and continuous sneezing which was very frequent. The symptoms worsened with time. Based on the above information, answer the following questions.
    (i) What could be the possible reason for Adityas condition?

    (a) Allergy (b) Infection (c) Malnutrition (d) Genetic disorder

    (ii) How can allergy be diagnosed in a person?

    (a) Presence of large amount of IgE antibodies in the blood (b) Presence of large number of bacteria in the blood
    (c) Presence of bilirubin and bilirubin pigments in the stool (d) Presence of sickle shaped RBCs in the blood

    (iii) The symptoms which Aditya developed on account of being allergic are consequence of

    (a) inflammation of membrane lining the nose and conjunctiva (b) swelling up of tissue surrounding bronchioles of lungs
    (c) dilation of all arteries so that large amount of fluid passes from blood to tissues. (d) all of these

    (iv) Name the type of allergy that Aditya developed.

    (a) Allergy (b) Anaphylaxis (c) Hay fever (d) Urticaria

    (v) Assertion: Hay fever is the form of allergy due to pollens of grasses and other plants.
    Reason : Hay fever symptoms are due to release of histamines and often respond well to treatment with antihistamines.

    (a) Both assertion and reason are true and reason is the correct explanation of assertion. (b) Both assertion and reason are true but reason is not the correct explanation of assertion.
    (c) Assertion is true but reason is false. (d) Both assertion and reason are false.

CBSE 12th Standard Biology Subject Case Study Questions With Solution 2021 Part - I - by Shweta Sharma - Anantapur - May 21, 2021 - View & Read

  • 1)


    The stages in the binary fission of Amoeba are shown above.
    (a) Arrange the stages in their proper natural sequence in binary fission.
    (b) How does this differ from the process of sporulation employed by Amoeba?

  • 2)


    Identify the types of gametes and give an example for each of A, Band C shown in tbe diagram, given below.

  • 3)


    These pictures show the gynoecium of A. Papaver and B. Michelia.
    (a) Write one similarity and one difference between the two.
    (b) Name the three parts of a pistil.

  • 4)


    Identify the types of flowers A and B on the Commelina plant shown above.
    (b) Mention the type(s) of pollination that can occur in each of them.

  • 5)


    A Human Spermatozoan
    A diagrammatic sketch of a human sperm is given. Identify the parts labelled A, Band C and mention their respective functions.

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12th Standard CBSE Biology Human Reproduction Important Questions - by Shweta Sharma - Anantapur - Apr 24, 2021 - View & Read

  • 1)

    Write two major functions each of testis and ovary.

  • 2)

    Define spermiogenesis and spermiation

  • 3)

    What is parturition? Which hormones are involved in induction of parturition?

  • 4)

    How many eggs do you think were released by the ovary of a female dog which gave birth to 6 puppies?

  • 5)

    What is menstrual cycle? Which hormones regulate menstrual cycle?

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