12th Standard CBSE Biology Study material & Free Online Practice Tests - View Model Question Papers with Solutions for Class 12 Session 2020 - 2021
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Biology Question Papers

Class 12th Biology -Environmental Issues Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

  • 1)


    A schematic representation of the functioning of an electrostatic precipitator is given above. Answer the following questions:
    (a) ame two sites where installation of electrostatic precipitator is necessary.
    (b) Mention a drawback of an electrostatic precipitator.
    (c) How does a scrubber differ from this?

  • 2)

    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.

  • 3)


    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.

  • 4)

    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?.

  • 5)

    DDT content in the water of a lake that supplies drinking water to the nearby villages was found to be 0.004 ppm. The pelicans of that area are reported to have 2.6 ppm of DDT. Answer the following questions based on the above observation.
    (a) Why has the concentration of DDT increased in these birds?
    (b) What possible harm will this cause to the bird population?
    (c) Name the phenomenon.

Class 12th Biology -Biodiversity and Conservation Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

  • 1)

    The global animal diversity is shown in the pie charts (A-Invertebrates and B-Ve.rtebrates) 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.

Class 12th Biology - Ecosystem Case Study Questions and Answers 2022 - 2023 - by Study Materials - 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 offood 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 ofthe above trophic levels, from the following list of organisms: Rabbit, Wolf, phytoplanktons, frog, snail, Hydrilla, jackal.

  • 5)


    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.

Class 12th Biology - Organisms and Populations Case Study Questions and Answers 2022 - 2023 - by Study Materials - 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)

    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.

  • 3)

    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.

  • 4)

    '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).

  • 5)


    (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?

Class 12th Biology - Biotechnology and its Applications Case Study Questions and Answers 2022 - 2023 - by Study Materials - 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)

    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.

  • 3)

    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?

  • 4)

    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.

  • 5)

    For effective treatment of a disease, early diagnosis and understanding its pathophysiology is important But, the presence of a pathogen is normally suspected, only when the pathogen produces the symptom(s) of the disease. By this time, the concentration of the pathogen must have become very high in the body.
    (a) Expand PCR.
    (b) How is it used in early diagnosis of a disease?
    (c) ame a disease for the detection of which PCR is routinely used.
    (d) Name two other molecular diagnostics used in early detection of diseases.

Class 12th Biology - Biotechnology: Principles and Processes Case Study Questions and Answers 2022 - 2023 - by Study Materials - 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.

Class 12th Biology - Microbes in Human Welfare Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

  • 1)

    Microbes are the major components of biological systems on this earth. Microbes are omnipresent, i.e., they are present every where in the soil, water, air, inside the bodies of plants, animals and humans.
    (a) Microbes are present even in such places, where no other life forms could possibly exist. Name two such places.
    (b) Name two groups of microbes that can be grown on nutrient media to form colonies.
    (c) Write the scientific name of the microbe employed in fermenting malted cereals and fruit juices.

  • 2)

    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.

  • 3)

    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.

  • 4)

    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?

  • 5)

    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.

Class 12th Biology - Strategies for Enhancement in Food Production Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

  • 1)

    Following are the steps in MQET (Multiple Ovulation Embryo Transfer) programme for the improvement of herd, in which a cow has been administered hormones with FSH-like activity.
    (a) Arrange the steps A to D in their correct sequence:
    A. Transferred to a surrogate mother.
    B. It is mated with an elite bull or artificially inseminated.
    C. Fertilised eggs at 32-celled stage are recovered non-surgically.
    D. It produces 6-8 eggs instead of one egg which they normally yield per cycle.
    (b) Why was the cow administered hormones with FSH-like activity?

  • 2)

    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.

  • 3)

    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.

  • 4)

    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.

  • 5)

    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.

Class 12th Biology - Human Health and Disease Case Study Questions and Answers 2022 - 2023 - by Study Materials - 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)

    The structure of an antibody molecule is given below. Answer the questions that follow:

    (a) Why are they said to show humoral immune response?
    (b) Name any four types of antibodies produced in our body.

  • 3)

    A youth in his twenties met with an accident and succumbed to the injuries. His parents agreed to donate his organs. Answer the following questions:
    (a) List any two essential clinical steps to be undertaken before any organ transplant.
    (b) Why is the organ transplant rejected sometimes? Name the kind of immunity responsible for this.

  • 4)

    Following a road accident, four injured persons were brought to a nearby clinic. The doctor immediately injected them with tetanus antitoxin,
    (a) What is tetanus antitoxin?
    (b) Why were the injured immediately injected with this antitoxin?
    (c) Name the kind of immunity this injection provided.

  • 5)

    A diagrammatic representation of the lymph vessels, lymph nodes and thymus is shown below.

    (a) Identity (I) a primary and (it) a secondary lymphoid organ from the diagram.
    (b) Mention the function of each of them.

Class 12th Biology - Evolution Case Study Questions and Answers 2022 - 2023 - by Study Materials - 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.

Class 12th Biology - Molecular Basic of Inheritance Case Study Questions and Answers 2022 - 2023 - by Study Materials - 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)


    Given above is the electron micrograph (EM) picture of 'beads-on-string'.
    a) What do the 'beads' represent?
    (b) What do they constitute in a eukaryotic nucleus? When does its maximum condensation occur in a ceU?
    (c) What is the function of non-histone chromosomal proteins in the nucleus?

  • 3)


    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?

  • 4)


    A DNA replication fork is shown above. Answer the following questions based on that.
    (a) Identity the polarity of the strands a - b and c-d.
    (b) Name the enzyme that catalyses the process.
    (c) What are the newly synthesised strands A - B and C - D known as?

  • 5)


    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.

Class 12th Biology - Principles of Inheritance and Variation Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

  • 1)


    Look at the cross given above and answer the following questions:
    (a) Give the genotypes of A, B, C and D.
    (b) Write the phenotypic ratio.
    (c) What type of a cross is this?

  • 2)

    Two independent monohybrid crosses were carried out involving a tall pea plant with a dwarf pea plant. In the first cross, the offspring population had equal number of tall and dwarf plants, whereas in the second cross, it was different. Work out the crosses and explain giving reasons for the difference in the offspring populations.

  • 3)

    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.

  • 4)

    Given below is a table showing the genotypes and the phenotypes of blood groups in the human population.

    (a) Identity the genotypes (W) and (X) and the phenotypes (Y) and (Z).
    (b) Name the pattern of inheritance exhibited by the phenotypes (Y) and (Zlgiven in the table.

  • 5)

    In pea plants, let symbol Y represent dominant yellow, symbol y, the recessive green, symbol R, the round seed shape, and symbol r, the wrinkled seed shape. A typical Mendelian dihybrid cross was carried out starting with homozygous dominant and recessive parents.
    Answer the following questions.
    (a) Write the genotype and phenotype of the F1offspring.
    (b) The genetic make up of the gametes produced by F1 individual.
    (c) Give the phenotypic ratio of F2 generation.

Class 12th Biology - Reproductive Health Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

  • 1)

    The population of India which was approximately 350 million at the time of independence crossed one billion in May, 2000. At the current rate of growth (17/1000/year), the population will double in 33 years. It will lead to scarcity of the basic needs like food, shelter, clothing, etc. So, the Government is forced to take some serious measures to control the population growth.
    Mention three steps the Government has taken to control the growth of population.

  • 2)


    a) Identify the male and the female contraceptive devices, A and B.
    (b) How do they prevent conception?
    (c) Mention two advantages (other than contraception), why they are preferred.

  • 3)


    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.

  • 4)


    (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?

  • 5)


    Shown above is the surgical method of contraception in human males.
    Answer the following questions:
    (a) Give the technical term for the process shown above.
    (b) What is the principle behind it as a contraceptive method?
    (c) How is the process carried out?

Class 12th Biology - Human Reproduction Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

  • 1)


    A diagrammatic sketch of the human male reproductive system is given above.
    (a) Identify and name the three glands associated with the human male reproductive system. What is the term given to their secretions?
    (b) Name the primary sex organ and the pouch in which it is located in human beings.

  • 2)


    A Human Spermatozoan
    A diagrammatic sketch of a human sperm is given. Identify the parts labelled A, Band C and mention their respective functions.

  • 3)

    Study the following flow chart and answer the questions that follow:

  • 4)


    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?

  • 5)


    (A) In the diagrammatic sectional view of a human ovary, identify the following:
    (i) Corpus luteum
    (ii) Antrum
    (iii) Secondary oocyte
    (iv) Primary follicle
    (B) Name the hormone that
    (i) influences the formation of corpus luteum.
    (ii) is secreted by corpus luteum.

Class 12th Biology - Sexual Reproduction in Flowering Plants Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

  • 1)

    The pollen grains may be shed at the two-celled stage (as in 60 per cent of angiosperms) or in the three-celled stage (as in the remaining species). When once shed, the pollen grains must land on the correct type of stigma before they lose viability, to effect fertilisation.
    (a) The period for which the pollen grains remain viable is highly variable depending on the species. Substantiate the statement with two examples.
    (b) Mention two environmental factors, which affect the pollen viability.

  • 2)


    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.

  • 3)


    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.

  • 4)


    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.

  • 5)


    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.

Class 12th Biology - Reproduction in Organisms Case Study Questions and Answers 2022 - 2023 - by Study Materials - 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)


    (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.

  • 5)

    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.

CBSE 12th Standard Biology Subject Human Health and Disease Value Based Questions 5 Marks Questions With Solution 2021 - by Shweta Sharma - Anantapur - 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)

    Modern life style in big cities and towns is surely making the life more easy and comfortable for people. On the contrary many more health issues and problems are on the rise and one of them is allergic reactions.
    (a) Write any four steps you would suggest to rninirnise the cause of the above allergic responses
    (b) List any two allergens. How does the human body respond to them? Explain

  • 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.

12th Standard CBSE Mathematics Public Exam Model Question 2020 - by Shweta Sharma - Anantapur - View & Read

  • 1)

    When seeds are attached to parent plant the type of germination is known as

  • 2)

    Which one of the following pollinations is autogamous?

  • 3)

    Which layer develops first during embryonic development?

  • 4)

    Given below are four methods (A-D) and their modes of action (i) - (iv) in achieving contraception. Select their correct matching from the four options that follow

    Method Mode of Action
    (A) The pill (i)  Prevents sperms reaching cervix
    (B) Condom (ii) Prevents implication
    (C) Vasectomy (iii)Prevents ovulation 
    (D) Copper T (iv)Semen contains no sperms
  • 5)

    Mendel's Law of independent assortment holds good for genes situated on the :

12th Standard CBSE Biology Public Exam Sample Question 2020 - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Which of the following statements is true of yeast?

  • 2)

    Choose the mismatched option

  • 3)

    In females, the hormone inhibin is secreted by

  • 4)

    The technique called Gamete Intra Fallopian Transfer (GIFT) is recommended for those females

  • 5)

    Male and female sex chromosomes are also called

12th Standard CBSE Biology Public Exam Important Question 2019-2020 - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Offsprings formed by sexual reproduction exhibit more variation than those formed by asexual reproduction because:

  • 2)

    Male gametes in angiosperms are formed by the division of

  • 3)

    If mammalian ovum fails to get fertilized, which one of the following is unlikely?

  • 4)

    Which of the following is the component of oral pills?

  • 5)

    Which one of the following conditions correctly describes the number of determining the sex?

12th Standard Biology Board Exam Sample Question 2020 - by Shweta Sharma - Anantapur - View & Read

  • 1)

    When seeds are attached to parent plant the type of germination is known as

  • 2)

    Chiropterophily means...

  • 3)

    The embryo at 16 celled stage is known as

  • 4)

    Which one of the following is the most widely accepted method of contraception in India at present?

  • 5)

    In a dihydrid cross where two parents differ in two pairs of contrasting traits like seed colour yellow (YY) and seed colour green (yy) with seed shape round (RR) and seed shape wrinkled (rr), the number of green coloured seeds (yy) among sixteen products of F2 generation will be

12th Standard Biology Board Exam Model Question 2019-2020 - by Shweta Sharma - Anantapur - View & Read

  • 1)

    External fertilization occurs in majority of

  • 2)

    While planning for an artificial hybridization programme involving dioecious plants, which of the following steps will be irrelevent:

  • 3)

    About which day in a normal human menstrual cycle does rapid secretion of LH (popularly called LH surge) normally occurs?

  • 4)

    Which of the following birth control measures can be considered as the safest?

  • 5)

    A human male produces sperms with the genotypes AB, ab, aB and ab pertaining to the diallelic characters in equal proportions. What is the corresponding genotype of this person?

12th CBSE Biology - Public Model Question Paper 2019 - 2020 - by Shweta Sharma - Anantapur - View & Read

  • 1)

     All data palm plants bear flowers but fruits are seen in some.  Explain.

  • 2)

    What is the figure given below showing in particular?

  • 3)

    What is LSD?

  • 4)

    Given below is the representation of a kind of chromosomal mutation

    What is the kind of mutation represented?

  • 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 Biology - Environmental Issues Model Question Paper - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Which one of the following is a pair of endangered species?

  • 2)

    India became a party to 'Convention on Biological Diversity'in the year

  • 3)

    the natural habitat of Indian Rhinoceros is found in which Indian state?

  • 4)

    Total number of identified biodiversity hotspots in the world is

  • 5)

    India has only 2-4% of the world's land area but its share of the global species diversity is

CBSE 12th Biology - Biodiversity and Conservation Model Question Paper - by Shweta Sharma - Anantapur - View & Read

  • 1)

    The noise produced in office is normally at the level of

  • 2)

    This acts as bioindicator of air pollution

  • 3)

    Which of the following is biogas?

  • 4)

    Which one of the following is an environment related disorder with the correct main cause?

  • 5)

    Greenhouse effect is due to

CBSE 12th Biology - Ecosystem Model Question Paper - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Secondary producers are

  • 2)

    Which of the following represents the sedimentary type of nutrient cycle?

  • 3)

    Which of the following is a free living nitrogen fixing bacteria present in soil?

  • 4)

    Maximum absorption of rainfall water is done by 

  • 5)

    Given is one of the types of ecological pyramids. This type represents

CBSE 12th Biology - Organisms and Populations Model Question Paper - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Maximum growth rate occurs in 

  • 2)

    Zone of atmosphere near the earth surface is 

  • 3)

    A terrestrial animal must be able to

  • 4)

    What is a keystone species?

  • 5)

    The term ecology was coined by

CBSE 12th Biology - Biotechnology and its Applications Model Question Paper - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Inseect resistance trangenic cotton has been produced by inserting a piece of DNA from

  • 2)

    Terminators gene

  • 3)

    Golden rice is a transgenic crop of the future with the following improved trail:

  • 4)

    Bacillus thuringiensis (Bt) strains have been used for designing novel

  • 5)

    Golden rice is a promising transgenic crop. When released for cultivation, it will help in

CBSE 12th Biology - Biotechnology: Principles and Processes Model Question Paper - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Viral genome incorporated into host DNA is called

  • 2)

    Plasmids are

  • 3)

    Which of the following is used as a best genetic vector in plants?

  • 4)

    The technique of genetic engineering includes

  • 5)

    The restriction enzyme(s) used in recombinant DNA technology that make staggered cuts in DNA leaving sticky ends is/are

CBSE 12th Biology - Microbes in Human Welfare Model Question Paper - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Lactic acid is formed by the process of

  • 2)

    A good example of organic fertilizer which improves phosphorus uptake is

  • 3)

    Which one of the following bacterium is used extensively as biopesticide?

  • 4)

    Cyclosporin-A an immunosuppressive drug is produced by

  • 5)

    Which one of the following is not used as a biopesticide?

CBSE 12th Biology - Strategies for Enhancement in Food Production Model Question Paper - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Which one of the following is not s secondary metabolite?

  • 2)

    In tissue cultural medium, the embryoids formed from pollen grains is due to

  • 3)

    Selection of homozygous plant is

  • 4)

    By which of the following methods, new and better varieties of plants can be formed? 

  • 5)

    The term 'totipotency' refers to the capacity of a:

CBSE 12th Biology - Human Health and Disease Model Question Paper - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Hashish and Ganja are got from

  • 2)

    Which of the following is not a component of innate immunity?

  • 3)

    Opiates (opium, heroin) are obtained from

  • 4)

    T-lymphocytes first mature in

  • 5)

    The term vaccine and vaccination were coined by

CBSE 12th Biology - Evolution Model Question Paper - by Shweta Sharma - Anantapur - View & Read

  • 1)

    The turtle and tortoise evolved from

  • 2)

    Which of the following walked upright?

  • 3)

    Which of the following is a living fossil?

  • 4)

    Which one of the following experiments suggest that simplest living organism could not having originated spontaneously from non-living matter?

  • 5)

    An important evidence in favour of organic evolution is the occurrence of

CBSE 12th Biology - Molecular Basic of Inheritance Model Question Paper - by Shweta Sharma - Anantapur - View & Read

  • 1)

    How many codons code for amino acids?

  • 2)

    How many base pairs are present in DNA cut by endonuclease

  • 3)

    DNA polymerase that helps in DNA replication is of

  • 4)

    During splicing, the exons are joined and the  enzyme which catalyzes this reaction is

CBSE 12th Biology - Principles of Inheritance and Variation Model Question Paper - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Heterozygous purple flower is crossed with recessive white flower. The progeny has the ratio :

  • 2)

    A self-fertilizing trihybrid plant forms

  • 3)

    A male human is heterozygous for autosomal genes A and B and is hemizygous for haemophilic gene h. What proportion of his sperms will be abh?

  • 4)

    Crossing over occurs between two homologous chromosomes in

  • 5)

    In a mutational event, when adenine is replaced by guanine, it is a case of

CBSE 12th Biology - Reproductive Health Model Question Paper - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Which of the following birth control measures can be considered as the safest?

  • 2)

    Which of the following is the component of oral pills?

  • 3)

    Choose the correct answer regarding the ZIFT procedure?

  • 4)

    It is a disease which mainly affects mucous membrane of urinogenital tract. In males, burning feeling on passing urine, after a yellow discharge occurs, that is accompanied by fever, headache and feeling of illness. Its name is

  • 5)

    Which one of the following groups includes all sexually transmitted diseases?

CBSE 12th Biology - Human Reproduction Model Question Paper - by Shweta Sharma - Anantapur - View & Read

  • 1)

    In human beings, the eggs are:

  • 2)

    Foetal ejection reflex in human female is induced by

  • 3)

    A change in the amount of yolk and its distribution in the egg will affect

  • 4)

    Which one of the following statements is false in respect of viability of mammalian sperm?

CBSE 12th Biology - Sexual Reproduction in Flowering Plants Model Question Paper - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Intraspecific incompatability can be overcome by

  • 2)

    Insect-pollinated flowers are characterized by

  • 3)

    An ovule which becomes curved so that the nucellus and embryo sac lie at right angles to the funicle is

  • 4)

    In some plants anthers and stigma grow and mature at the same time.This phenomenon is called

  • 5)

    Identify the wrong statement regarding post-fertilization development

CBSE 12th Biology - Reproduction in Organisms Model Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Which of the following statement is true of Hydra?

  • 2)

    Which of the following statements true of date plam?

  • 3)

    Spermatids are transformed into spermatozoa by

  • 4)

    Study of pollen grain is called

  • 5)

    vegitative propagation in mint occurs by 

CBSE 12th Biology - Full Syllabus One Mark Question Paper with Answer Key - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Which of the following statements is true of yeast?

  • 2)

    Which one of the following statements is true of cucurbits?

  • 3)

    Transverse binary fission occurs in

  • 4)

    In which of the following organism, self-fertilization is seen?

  • 5)

    Which of the following animal is having longitudinal binary fission?

CBSE 12th Biology - Full Syllabus Five Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Name the three events in the sexual reproduction of an angiosperm and mention what major events occur in each of them.

  • 2)

    Explain the development of the zygote into an embryo and of the primary endosperm nucleus into an endosperm in a fertilised embryo sac of a dicot plant. 

  • 3)

    Puneet used to like beautiful flowers but not the insects flying in the garden.He discussed his plan but his father advised him not to do so as it will affect seed formation in ornamental plants of the garden.
    Read the above passage and answer the following questions:
    (i) Was the decision of Puneet to kill insects of garden with insecticide right?
    (ii) Why did his father advise him not to do so?
    (iii) Are chemical insecticides safe for living organisms including human beings?

  • 4)

    Give the structure of simple type placenta.

  • 5)

    Let us assume in a given plant, the genotype symbol 'Y' stands for dominant yellow seed colour and 'Y' for recessive green seed colour; symbol 'R' for round seed shape and 'r' for wrinkled seeds.  Two homozygous parents (plant) with genotypes 'RRYY' and 'rryy' are crossed and their F1 generation progeny is then 
    (a) Phenotype of F1 progeny
    (b) Genotype of F1 Progeny
    (c) Gamete genotypes of F1 progeny
    (d) Phenotypic ratio of F2 population
    (e) Phenotypic ratio of yellow seeds to green seeds and round seeds to wrinkled seeds in F2 population.

CBSE 12th Biology - Full Syllabus Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Why do we refer to offspring, formed by asexual method of reproduction as clones?

  • 2)

    Name the three parts of pistil and mention one function of each of them.

  • 3)

    What are the major fuctions of male accessory ducts and glands?

CBSE 12th Biology - Full Syllabus Two Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    The cell division involved in gamete formation is not of the same type in different organisms.  Justify.

  • 2)

    How do homogameters differ from heteroga-metes?

  • 3)

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

  • 4)

    Define ornithophily, chiropterophily and malacophily.

CBSE 12th Standard Biology - Environmental Issues Five Marks Model Question Paper - by Sunitha Vipinchandran - Palakkad - View & Read

  • 1)

    Expand FOAM. Describe the project of integrated waste water treatment, it it responsible for the upkeep.

  • 2)

    (a) Why is the ozone layer required in the stratosphere? How does it get degraded? Explain
    (b) Why is the ozone depletion a threat to mankind?

  • 3)

    Discuss briefly Radioactive wastes.

  • 4)

    Discuss briefly the defunct ships and e-wastes.

  • 5)

    What are the basic characteristics of a modern landfill site. List any three and also mention the reasons for their use.

12th CBSE Biology - Biodiversity and Conservation Five Marks Model Question Paper - by Sunitha Vipinchandran - Palakkad - View & Read

  • 1)

    Describe in detail the species-area relationship of biodiversity

  • 2)

    Explain briefly the 'rivet popper hypothesis' of Paul Ehrlich.

  • 3)

    Explain effects of habitat fragmentation on biodiversity.

  • 4)

    List the three types of extinction processes.

  • 5)

    List the uses of biodiversity.

12th Standard CBSE Biology - Ecosystem Five Marks Model Question Paper - by Sunitha Vipinchandran - Palakkad - View & Read

  • 1)

    Explain the different steps involved in the process of decomposition of detritus.

  • 2)

    List the different steps and state their role in the process of decomposition in an ecosystem.

  • 3)

    Describe the components of an ecosystem.

  • 4)

    Give an account of energy flow in an ecosystem.

  • 5)

    "The energy flow in the ecosystem follows the second law of thermodynamics". Explain.

12th Standard CBSE Biology - Organisms and Populations Five Marks Model Question Paper - by Sunitha Vipinchandran - Palakkad - View & Read

  • 1)

    (a) Explain with the help of a graph, the population growth curve when resources are
    (i) limiting and
    (ii) not limiting.
    (b) 'Nature has a carrying capacity for a species'.  Explain.

  • 2)

    List the different ways by which organisms cope or manage with abiotic stresses in nature.  Explain any three ways listed.

  • 3)

    List any three important characteristics of a population and explain.

  • 4)

    Define commensalism.  Describe any four examples.

  • 5)

    What is mutualism? Describe any four examples.

12th CBSE Biology - Biotechnology and its Applications Model Question Paper - by Sunitha Vipinchandran - Palakkad - View & Read

  • 1)

    Name the process involved in the production of nematode - resistant tobacco plants, using genetic engineering. Explain the strategy adopted to develop such plants.

  • 2)

    (a) Name the nematode that infects and damages tobacco roots.
    (b) How are transgenic tobacco plants produced to solve this problem?

  • 3)

    What is ADA deficiency? Describe three methods to cure it.

  • 4)

    Explain the steps involved in the production of genetically engineered insulin why is the insulin thus produced preferred to the one produced from non- human sources?

  • 5)

    What are transgenic animals? Explain any four ways in which such animals can be beneficial to humans.

12th Standard CBSE Biology - Biotechnology: Principles and Processes Five Marks Model Question Paper - by Sunitha Vipinchandran - Palakkad - View & Read

  • 1)

    (a)With the help of diagrams show the different steps in the formation of recombinant DNA by action of restriction endonuclease enzyme EcoRI.
    (b)Name the technique that is used for separating the fragments of DNA cut by restriction endonucleases.

  • 2)

    Draw a labelled diagram of a simple stirred-tank bioreactor and describe its functionating.

  • 3)

    What is a bioreactor? Draw a labelled diagram of a sparged stirred-tank-bioreactor. Explain its functionating.

  • 4)

    Describe briefly the bioreactors.

  • 5)

    How do bioreactors help in production of recombinant proteins?

CBSE 12th Biology - Environmental Issues Five Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Describe the functioning of electrostatic precipitator along with a schematic diagram.

  • 2)

    Expand FOAM. Describe the project of integrated waste water treatment, it it responsible for the upkeep.

  • 3)

    Name the major atmospheric pollutants and their sources.

  • 4)

    What is air pollution? Write the preventive measures for air pollution. 

  • 5)

    Why is ozone layer in stratosphere called a protective layer?

CBSE 12th Biology - Biodiversity and Conservation Five Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Describe in detail the species-area relationship of biodiversity

  • 2)

    (a) What are the two types of desirable approaches to conserve biodiversity? Explain with examples bringing out the difference between the two types.
    (b) What is the association between the bumble bee and its favourite orchid,Ophrys? How would extinction or change of one would affect the other?

  • 3)

    Species diversity decrease as we move away from the equator towards the poles. what could be the possible reasons?

  • 4)

    Explain briefly the 'rivet popper hypothesis' of Paul Ehrlich.

  • 5)

    List the uses of biodiversity.

12th Standard CBSE Biology - Ecosystem Five Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    List the different steps and state their role in the process of decomposition in an ecosystem.

  • 2)

    Explain the carbon cycle with the help of a simplified model.

  • 3)

    'All successions proceed to a similar climax community,the mesic'.Explain.

  • 4)

    Describe the components of an ecosystem.

  • 5)

    (a) Draw a 'pyramid of numbers' of a situation, where a large population of insects fed upon a very big tree.The insects in turn are eaten by small birds,which in turns are fed upon by birds.

12th Standard CBSE Biology - Organisms and Populations Five Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    (a) Explain with the help of a graph, the population growth curve when resources are
    (i) limiting and
    (ii) not limiting.
    (b) 'Nature has a carrying capacity for a species'.  Explain.

  • 2)

    With the helps of a suitable diagram describe the logistic population growth curve.

  • 3)

    Define the following terms and give one example for each.
    (a) Commensalism    
    (b) Parasitism    
    (c) Camouflage    
    (d) Mutualism    
    (e) Interspecific competition.

  • 4)

    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?

  • 5)

    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.

12th Standard CBSE Biology - Biotechnology and its Applications Five Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Compare and constrast the advantages and disadvantages of production of genetically modified crops.

  • 2)

    What is gene therapy? Illustrate using the example of adenosine deaminase (ADA?) deficiency.

  • 3)

    (i) What are the three options that can be thought of, to increase food production?
    (ii) Mention the reasons for the success of green revolution in increasing food production.
    (iii) Why do we still search for other alternatives to increase food production?

  • 4)

    Define transgenic animals. Explain any four areas where they can be utilised.

  • 5)

    List the advantages of recombinant insulin.

CBSE 12th Biology - Biotechnology: Principles and Processes Five Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    (a)Mention the role of vectors in recombinant DNA technology. Give any two examples.
    (b)With the help of diagrammatic representation only, Show the steps of recombinant DNA technology.

  • 2)

    Can you list 10 recombinant proteins which are used in medical practice. Find where they are used as therapeutics.

  • 3)

    What are bioreactors? Sketch the two types of bioreactors. What is the utility? Which is the common type of bioreactors?

  • 4)

    How do bioreactors help in production of recombinant proteins?

  • 5)

    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 ?

CBSE 12th Biology - Microbes in Human Welfare Five Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    What are biofertilisers? Name the categories of used as biofertilisers with an example for each.How do they function in organic farming?

  • 2)

    Ganga has recently been declared the national river. Discuss the implication with respect to pollution of this river.

  • 3)

    (a) Discuss about the major programs that the Ministry of Environment and Forests, Government of India, has initiated for saving major Indian rivers from pollution.

  • 4)

    (a) What would happen if a large amount of untreated sewage is discharged into a river?
    (b) In what way anaerobic sludge digestion is important in sewage treatment?

  • 5)

    Which type of food would contain lactic acid bacteria? Discuss their useful application.

CBSE 12th Biology - Molecular Basic of Inheritance Five Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Enlist the salient features o the double helix strucutre of DNA.

  • 2)

    Describe the process of DNA replication.

  • 3)

    (i)What are the three types of RNA?
    (ii)Which one of these has the shape of a clover leaf in two-dimentional structure?
    (iii)How is each RNA related in the information during protein synthesis?Explain.

  • 4)

    What is genetic code?Name the scientists and their contribution in deciphering the genetic code

  • 5)

    Describe the steps involved in the sequencing of genome of an organism.

CBSE 12th Biology - Evolution Five Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Explain in detail the different theories of origin of life.

  • 2)

    Show that Darwin's natural selection is based on factual observations, with an example for each.

  • 3)

    State the hypothesis of Oparin and Haldane about the primeval Earth condition. What do you understand by Haldane's hot, dilute soup? State its significance.

  • 4)

    How did Louis Pasteur successfully demolish the popular theory of spontaneous generation? What were his conclusions?

  • 5)

    Distinguish between microevolution and macroevolution. Narrate the significance of population genetics in evolution.

CBSE 12th Biology - Strategies for Enhancement in Food Production Five Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Enumerate the points that have to be considered for successful bee-keeping.

  • 2)

    How are morphological and biochamical/physiogical charracteristics of plants associated with resistance to insect pets? Give any five examples of the features and the name of the pest, which each is resistant to.

  • 3)

    Discuss advantages of poultry farming.

  • 4)

    Write a brief account of procedure of Inland Fishery.

  • 5)

    Discuss the role of plant tissue culture in increasing food production.

CBSE 12th Biology - Human Health and Disease Five Marks - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Explain the different ways of diagnosing cancer.

  • 2)

    Describe the different methods of treatment of cancer.

  • 3)

    Why do some adolescent start taking drugs?How can this be avoided.

  • 4)

    In your locality, if a person is addicted to alcohol,what kind of behavioural changes do you observe in that person?Suggest measures to overcome the problem.

  • 5)

    Write the causative organism, mode of infection, symptoms and preventive measures of
    (1)Leprosy
    (2)Whooping cough

CBSE 12th Biology - Principles of Inheritance and Variation Five Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    (a) State the cause and symptoms of Down's syndrome.  Name and explain the event responsible for causing this syndrome.
    (b) Haemophilia and Thalassemia are both examples of Mendelian disorders, but show differences in their inheritance pattern.  Explain how.

  • 2)

    Differentiate between the following:
    (a) Polgenic inheritance and Pleiotropy
    (b) Dominance, Codominance and Incomplete dominance

  • 3)

    (a) Explain the genetic basis of ABO blood groups in human population.
    (b) How do ABO blood groups explain the phenomena of dominace and codominance?

  • 4)

    Describe the mechanism of pattern of inheritance of ABO blood groups in humans.

  • 5)

    Haemophilia and sickle-cell anaemia are blood related Mendelian disorders. Yet, they differ in their pattern of inheritance. Explain the difference.

12th Standard CBSE Biology - Reproductive Health Five Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Mention the different ways in which people are made aware of the significance of reproductive health and a reproductively healthy society.

  • 2)

    How can education help in building up a socially responsible and reproductively healthy society?
    (Enumerate the aspects that should be emphasised).

  • 3)

    STDs are a threat to reproductive health.Describe any two such diseases and suggest preventive measures.

  • 4)

    What is census? What is Indian population as per census of 2001?

  • 5)

    Define population density.What are consequences of high population density?

CBSE 12th Standard Biology - Microbes in Human Welfare Five Mark Model Question Paper - by Sunitha Vipinchandran - Palakkad - View & Read

  • 1)

    Arrange the following in the decreasing order (most important first) of their importance, for the welfare of human society. Give reasons for your answer. Biogas,citric acid,Penicillin and curd.

  • 2)

    Why is aerobic degradation more important than anaerobic degradation for the treatment of large volumes of waste water in organic matter. Discuss.

  • 3)

    (a) Discuss about the major programs that the Ministry of Environment and Forests, Government of India, has initiated for saving major Indian rivers from pollution.

  • 4)

    Which type of food would contain lactic acid bacteria? Discuss their useful application.

  • 5)

    Explain biological control of pests and plant pathogens with examples.

12th CBSE Biology - Strategies for Enhancement in Food Production Five Mark Model Question Paper - by Sunitha Vipinchandran - Palakkad - View & Read

  • 1)

    Name the methods employed in animal breeding.According to you which one of the methods is the best? Why?

  • 2)

    What are three option to increase food production? Discuss each giving the salient features, merits and demerits.

  • 3)

    Briefly give an account of common diseases of fishes and the control of such diseases.

  • 4)

    Discuss advantages of poultry farming.

  • 5)

    Discuss the role of plant tissue culture in increasing food production.

12th CBSE Biology - Human Health and Disease Five Mark Model Question Paper - by Sunitha Vipinchandran - Palakkad - View & Read

  • 1)

    Describe the asexual and sexual phases of life cycle of Plasmodium that causes malaria in humans.

  • 2)

    Why do some adolescent start taking drugs?How can this be avoided.

  • 3)

    What is Pulse Polio Programme of  Government of India? What is OPV? Why is it that India is yet to eradicate Pollio.

  • 4)

    Why is penicillin not effective in primary atypical pneumonia?

  • 5)

    Answer the following questions:
    (a) How are the cancer cells different from normals cells?
    (b) Pick out correct carcinogens out of the following :
    Asbestos, infra red rays, arsenic, polythene, casein, caffein, tobacco smoke, Gamma rays.
    (c) Write down three methods (write full forms wherever required) to detect cancer of internal organs.

12th CBSE Biology - Evolution Five Mark Model Question Paper - by Sunitha Vipinchandran - Palakkad - View & Read

  • 1)

    (a) List the various causes of variations in the progeny of a population.
    (b) Describe the three different ways in which natural selection operates in nature, with regard to organic evolution.

  • 2)

    (a) Name the primates that lived about 15 million years ago. List their characteristic features.
    (b) (i) Where was the first man-like animal found?
    (ii) Write the order in which Neanderthals, Homo habilis and Homo erectus appeared on the earth. State the brain capacity of each one of them.
    (iii) When did modern Homo sapiens appear on this planet?

  • 3)

    (a) Explain taking one example of vertebrate anatomy, that evolution of life has occurred on earth.
    (b) 'Nature selects for fitness'. Explain with suitable example.

  • 4)

    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?

  • 5)

    Two organisms occupying particular geographical area show similar adaptive strategies. Taking examples, describe the phenomenon.

12th Standard CBSE Biology - Human Reproduction Five Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Identify True/False statements.Correct each false statement to make it true:
    (a) Androgens are produced by Sertoli cells.(True/False)
    (b) Spermatozoa get nutrition from Sertoli cells. (True/False)
    (c) Leydig cells are found in ovary. (True/False)
    (d) Leydig cells synthesise androgens. (True/False)
    (e) Oogenesis takes place in corpus luteum. (True/False)
    (f) Mentrual cycle ceases during pregnancy. (True/False)
    (g) Presence or absence of hymen is not a reliable indicator of virginity or sexual experience. (True/False)

  • 2)

    (a) Humans reproduce ____________.((asexually/sexually)
    (b) Humans are ____________.(oviparous,viviparous,ovoviviparous)
    (c) Fertilisation is ____________.in humans.  (external/internal)
    (d) Male and female gametes are ____________. (diploid/haploid)
    (e) Zygote is ____________. (diploid/haploid)
    (f) The process of release of ovum from mature follicle,is called. ____________.
    (g) Ovulation is induced by a hormone,called ____________.
    (h) The fusion of male and female gametes,is called ____________.
    (i) Fertilisation takes place in ____________.
    (j) Zygote divides to form ____________. which is implanted in uterus.
    (k) The structure which provides vascular connection between foetus and uterus,is called ____________.

  • 3)

    What roles does pituitary gonadotrophins play during follicular and ovulatory phases of menstrual cycle? Explain the shifts in steroidal secretions. 

  • 4)

    The zygote passes through several development stages till implantation.Describe each stage briefly with suitable diagrams.

  • 5)

    Describe the formation of three germ layers in a mammalian embryo.

CBSE 12th Biology - Sexual Reproduction in Flowering Plants Five Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    How does a pollen mother cell develop into a mature pollen grain? Illustrate the stages with labelled diagrams.

  • 2)

    (a) Differentiate between: Autogamy, geitonogamy and xenogamy.
    (b) Explain the events that occur during pollen-pistil interaction.

  • 3)

    (a) Describe the process of syngamy and triple fusion in angiosperms.
    (b) Explain the development of a fertilised egg upto a mature embryo in a dicot plant. draw a labelled diagram of a mature dicot embryo,

  • 4)

    (a) Draw a labelled schematic diagram of the transverse section mature anther of an angiospermic plant. 
    (b) Describe the characteristic features of an insect-pollinated flower.

  • 5)

    (a) Describe in sequence the process of megasporogenesis in angiosperms.
    (b) Draw the seven-celled structure formed and label all the different cells.

12th Standard CBSE Biology - Reproduction in Organisms Five Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    You must have seen your mother adding 3-4 globules of yeast to the idli paste she has prepared.  Similarly, brewing industry uses yeast in the manufacture of alcohol.
    (a) How does such a small amount of yeast added help to produce thousands of litres of alcohol? Explain how yeast multiples so fast.
    (b) Name the process carried out by yeast in these cases.
    (c) What value is learnt from these?

  • 2)

    A farmer cultivates sugar cane and rose by usin stem cuttings.  He found that some of the cuttings did not continue to grow into new plants.  As a student of Agriculture; Shanu gives some points to be followed.
    (a) Can you suggest a reason for this?
    (b) Enlist the aspects that Shanu must have given for consideration, while preparing stem cuttings for propagation.
    (c) Name two other plants which are also propagated by stem cuttings.
    (d) What value (s) is/are shown by Shanu?

  • 3)

    Jagan has two mango trees in the backyard  of his house, which yielded fruits for the first time during this summer.  The fruits were small, fibrous and not so sweet.  In the next house, where his friend Ajay livers, there is a mango tree, which yields fruits that are fleshy/juicy, very sweet and bigger in size.  Ajay, a student of B.sc. (Botany) comes out with an idea and takes some branches from the jagan's garden to his garden and explains the procedure.
    (a) What method do you think Ajay has suggested for getting good quality fruits, on the trees of Jagan's house in a short period of time, i.e. during the next season?
    (b) Describe how it is carried out to help japan.
    (c) What are its advantages over growing a mango tree with the seeds obtained from Ajay's garden?
    (d) Mention the values expressed by Ajay in this case.

  • 4)

    In nature, i,e in the wild, birds lay eggs seasonally during a particular time of the year, but in a poultry farm, eggs are produced throughout the year.
    (a) Give reason for this observation.    
    (b) Is it ethically/morally correct in your opinion? Justiy your argument.

  • 5)

    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.

CBSE Class 12th Biology - Strategies for Enhancement in Food Production Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Name the prominent south indian and north indian species of sugarcane used for cross-breeding. List the desired qualities of the hybird cane obtained form this cross.

  • 2)

    Describe the technology that sucessfully increased the herd size of cattle in a short time to meet demands of growing human
    population.

  • 3)

    Mention the property of plant cells that cells help them to grow into a new plant in vitro conditions.Explain the advantages of micropropagation.

  • 4)

    IARI has released several varieties of crop plants that are biofortified. Give three examples of such crop and their biofortificatuions.

  • 5)

    Why are plants obtained through micro-propagation termed somaclones? Name three food plants produced on commerical scale using this method.

CBSE Class 12th Biology - Microbes in Human Welfare Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Explain the role of the following in increasing the soil fertility and crop yield :
    (a) Leguminous plants
    (b) Cyanobacteria
    (c) Mycorrhizae

  • 2)

    Name the two different categories of microbes naturally occuring in sewage water.Explain their role in cleaning sewage water into usable water.

  • 3)

    Explain the role of baculoviruses as biological control agents. Mention their importance in organic farming

  • 4)

    Explain the different steps involved in sewage treatment before it can be released into natural water bodies.

  • 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 Class 12th Biology - Biotechnology: Principles and Processes Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Name and describe the technique that helps in separation and isolation of DNA fragments

  • 2)

    Name and explain the technique used in the separation and isolation of DNA fragments to be used in recombinant DNA technology.

  • 3)

    Explain the basis on which the gel electrophoresis technique works. Write and two ways the products obtained through this technique can be utilised.

  • 4)

    How is the amplification of a gene of interest carried out using polymerase Chain Reaction(PCR)?

  • 5)

    Explain the process by which a bacterial cell can be made 'competent'. Why is it essential to make bacterial cells 'competent in recombinant' to take up plasmid/rDNA.

CBSE Class 12th Biology - Biotechnology and its Applications Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Differentiate between diagnostics and therapeutics. Give one example for each category.

  • 2)

    Mention any six fields of applications of biotechnology for human welfare.

  • 3)

    What are the three critical reaseach areas of biotechnology?

  • 4)

    Mention the advantages of recombinant therapeutics. How many of them have been approved world over for human buse and how many are marketed in India?

  • 5)

    Enlist with examples the different groups of insects to which the crystal proteins are toxic.

CBSE Class 12th Biology - Organisms and Populations Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Water is very essential for life.  Write any three features both for plants and animals, which enable them to survive in water-scarce environment.

  • 2)

    How do organisms cope with stressful environmental conditions, which are localised or of short duration?

  • 3)

    How do organisms like fungi, zooplanktons and bears overcome the temporary, short-lived climatic stressful conditions?  Explain.

  • 4)

    write a short note on adaptations of desert plants and animals.

  • 5)

    Give and example for:
    (a) An endothermic animal.
    (b) An ectothermic animal.
    (c) An organism of benthic zone.

CBSE Class 12th Biology - Ecosystem Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    What is primary productivity? Give a brief description of factors that affect primary productivity.

  • 2)

    Give two examples of each of:
    (i) Terrestrial ecosystem
    (ii) Aquatic ecosystem
    (iii) Man-made ecosystem

  • 3)

    Describe the different classes of consumers.

  • 4)

    What is humus?Mention its properties.

CBSE Class 12th Biology - Biodiversity and Conservation Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    List the reasons that account for the greater biological diversity in tropics.

  • 2)

    Give three reasons as to why the prokaryotes are not given any figures for their diversity by the ecologist.

  • 3)

    Write an account on biodiversity in India.

  • 4)

    Describe with an example the latitudinal gradients of biodiversity

  • 5)

    Mention the three attributes that a stable community has.

CBSE 12th Biology - Environmental Issues Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Mention any six harmful effects of noise on human health/ body

  • 2)

    What are heavy metals? Give four examples.

  • 3)

    Draw a schematic labelled sketch of a scrubber and mention its use to remove pollutions.

  • 4)

    Eutrophication is the natural ageing of a lake.Explain

  • 5)

    How does eutrophication of a lake take place? Explain

CBSE 12th Biology - Human Health and Disease Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Trace the life cycle of malarial parasite in the human body,when bitten by an infected female Anopheles.

  • 2)

    Give the scientific name of the parasite that causes malignant malaria in humans.At what stage does this parasite enter the human body?Trace its life cycle is human body?

  • 3)

    Why are lymph nodes and bone marrow called lymphoid organs? Explain the functions of each of them.

  • 4)

    (a) Name the stage of Plasmodium that gains entry into the human body.
    (b) Trace the stages of Plasmodium in the body of female Anopheles after its entry.
    (c) Explain the cause of periodic recurrence of chill and high fever during malarial attack in humans.

12th Standard CBSE Biology - Evolution Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

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

  • 2)

    State the views of Oparin and Haldane on evolution. How does S.L. Miller's experiment Support their views?

  • 3)

    Branching descent and natural selection are the two key concepts of Darwinian theory of evolution. Explain each concept with the help of a suitable example.

  • 4)

    Convergent evolution and divergent evolution are the two concepts explaining organic evolution. Explain each one with the help of an example.

  • 5)

    Discovery of lobefins is considered very significant by evolutionary biologists. Explain.

12th Standard CBSE Biology - Molecular Basic of Inheritance Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    How are the structural genes activated in the lac operon in E.coli?

  • 2)

    Unambiguous universal and degenerate and some of the terms used for the genetic code.Explain the salient features of each one of them.

  • 3)

    What is meant by R-cells and S-cells with which Fredrick Griffith carried out his experiments on Diplococus pneumoniae? What did he prove from these experiments?

12th CBSE Biology - Principles of Inheritance and Variation Five Mark Question Paper - by Sunitha Vipinchandran - Palakkad - View & Read

  • 1)

    (a) Explain the mechanism of sex determination in humans.
    (b) Differentiate between male heterogamety and female heterogamety with the help of an example of each.

  • 2)

    Why is thalassemia categorised as a Mendelian disorder?  Write the symptoms and explain the cause of the disease.  How does it differ from the sickle-cell anaemia?

  • 3)

    (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.

  • 4)

    Explain the causes, inheritance patterns and symptoms of any two Mendelian genetic disorders.

  • 5)

    Haemophilia and sickle-cell anaemia are blood related Mendelian disorders. Yet, they differ in their pattern of inheritance. Explain the difference.

12th CBSE Biology - Molecular Basic of Inheritance Five Mark Question Paper - by Sunitha Vipinchandran - Palakkad - View & Read

  • 1)

    How did Meselson and Stahl experimentally prove that DNA replication is semiconservative? Explain.

  • 2)

    Who proposed that DNA replication is semicoservative? How did Meselson and Stahl prove it experimentally?

  • 3)

    Name the scientists who proved experimentally that DNA is the genetic material. Describe their experiment.

  • 4)

    How did Hershey and Chase prove that DNA is the heredity material? Explain their experiment with suitable diagrams.

12th Standard CBSE Biology - Reproductive Health Five Mark Question Paper - by Sunitha Vipinchandran - Palakkad - View & Read

  • 1)

    How can education help in building up a socially responsible and reproductively healthy society?
    (Enumerate the aspects that should be emphasised).

  • 2)

    Discuss the mode of action and advantages/disadvantages of hormonal contraceptives.

  • 3)

    Enumerate and describe any five reasons for sex education to school-going children.

  • 4)

    Explain the aspects of Demography.

  • 5)

    Define population density.What are consequences of high population density?

12th CBSE Biology - Human Reproduction Five Mark Question Paper - by Sunitha Vipinchandran - Palakkad - View & Read

  • 1)

    Write two differences between spermatogenesis and oogenesis.

  • 2)

    What roles does pituitary gonadotrophins play during follicular and ovulatory phases of menstrual cycle? Explain the shifts in steroidal secretions. 

  • 3)

    Describe the Similarities between Spermatogenesis and Oogenesis.

  • 4)

    Show with graphic sketch the hormonal control over the menstrual cycle.

12th CBSE Biology - Sexual Reproduction in Flowering Plants Five Mark Question Paper - by Sunitha Vipinchandran - Palakkad - View & Read

  • 1)

    (a) Differentiate between: Autogamy, geitonogamy and xenogamy.
    (b) Explain the events that occur during pollen-pistil interaction.

  • 2)

    How does the megaspore mother cell develop into a 7-celled, 8-nucleate embryo sac in an angiosperm? Draw a labelled diagram of a mature embryo sac.

  • 3)

    Describe contrivances for cross-pollination.

  • 4)

    Write a note on the development of endosperm. Mention the types with examples.

  • 5)

    Describe the structure of pollen grain.

12th CBSE Biology - Reproduction in Organisms Five Mark Question Paper - by Sunitha Vipinchandran - Palakkad - View & Read

  • 1)

    Distinguish between oviparous and viviparous animals.

  • 2)

    In the following figures label the parts responsible for production of new plants

  • 3)

    Which is a better mode of reproduction, sexual or asexual? why?

  • 4)

    (i) What are the three clear-cut phases in the life of annual and biennial type of plants?
    (ii) Why is it difficult to define these phases in perennial species of plants?

  • 5)

    Enumerate the differences between asexual and sexual reproduction. Describe the types of asexual reproduction exhibited by unicellular organisms.

12th Standard CBSE Biology - Principles of Inheritance and Variation Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Why are human females rarely haemophilic? Explain.  How do haemophilic patients suffer?

  • 2)

    Recently a girl baby has been reported to suffer from haemophilia.  How is it possible? Explain with the help of a cross.

  • 3)

    Name the phenomemon that leads to situations lie 'XO' abnormality in humans.  How do humans with 'XO' abnormality suffer? Explain.

  • 4)

    Name the genetic disorder caused by an extra 'X' chromosome in a human male.  State the diagnostic features of the individual suffering from it.

12th Standard CBSE Biology - Reproductive Health Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Suggest and explain any three Assisted Reproductive Technologies(ART) to an infertile couple

  • 2)

    How are assisted reproductive technologies helpful to humans? How are ZIFT and GIFT different from intrauterine transfers?Explain

  • 3)

    Mention any six reproduction-related problems/issues.

  • 4)

    Describe the three different practices under natural methods of birth control?Explain

  • 5)

    Describe the three manners in which fertilisation of human ovum by a sperm can be prevented.

CBSE 12th Biology Human Reproduction Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    (a) Draw a diagram of the structure of a human ovum surrounded by corona radiata.Label the following parts:
    (i) Ovum
    (ii) Plasma membrane
    (iii) Zona pellucida.
    (b) State the function of Zona pellucida .

  • 2)

    Name the source of gonadotropins in human females.Explain the changes brought about in the ovary by these hormones during menstrual cycle.

  • 3)

    Name the pituitary hormones influencing Leydig cells and Sertoli cells present in human testes.Explain the functions of these cells.

  • 4)

    What are the major fuctions of male accessory ducts and glands?

  • 5)

    How many eggs are released by a human ovary in a month? How many eggs do you think would have been released if the mother gave birth to identical twins?Would your answer change,if the twins born were fraternal?

12th CBSE Biology - Sexual Reproduction in Flowering Plants Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

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

  • 2)

    List the adaptive features of water-pollinated flowers like Vallisneria.

  • 3)

    Cleistogamous flowers of Commelina are invariably autogamous. Mention its one advantage and one disadvantage to the plant. 

  • 4)

    Write the cellular contents carried by the pollen tube. How does the pollen tube. How does the pollen tube gain its energy into the embryo sac?

CBSE 12th Biology Unit 1 Reproduction in Organisms Three Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Distinguish between asexual and sexual reproduction.  Why is vegetative reproduction also considered as a type of asexual reproduction?

  • 2)

    How does yeast reproduce asexually?  Show it diagrammatically.

  • 3)

    Describe the process of sporulation seen in Amoeba.

  • 4)

    Differentiate between external fertilisation and internal fertilisation with an example for each.

12th Standard CBSE Biology - Environmental Issues Two Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Name any two sources of e-wastes and write two different ways for their disposal.

  • 2)

    Mention how e-waste is produced and disposed off. Write the solution for its treatment.

  • 3)

    Refrigerants are considered to be a necessity in morsern living, but are said to be responsible ozone holes detected in Antarctica.Justify.

  • 4)

    Chlorofluorocarbons (CFCs) are widely used as refrigerants. Then why is it suggested to reduce its emission as far as possible? Explain.

  • 5)

    Thermal power plants are inevitable in an industrial and densely populated country like ours.What harm do they do to the environment? Also mention any precautions that could be taken to save our environment.

12th Standard CBSE Biology - Biodiversity and Conservation Two Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Why have certain regions been declared as biodiversity ' hot spots' by environmentalist of the wpold? Name any two hot spot regions of india.

  • 2)

    Why should biodiversity be conserved? List any two eithical arguments in its support.

  • 3)

    Justify with the help of an example where a deliberate attempt by humans has led to the extinction of a particular species.

  • 4)

    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 grater diversification?

  • 5)

    Can you think of a situation where we deliberately wnt to make a species extinct? How would you justify it?

12th Standard CBSE Biology - Ecosystem Two Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    'It is possible that a species may occupy more than one trophic level in the same ecosystem time'.Explain with the help of an example.

  • 2)

    Explain with the help of two examples,how the pyramid of number and the pyramid of biomass can look inverted.

  • 3)

    Distinguish between grazing food chain and detritus food chain.

  • 4)

    Distinguish between upright and inverted pyramids.

CBSE 12th Biology Unit 13 Organisms and Populations Two Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    How does Monarch butterfly defend itself from predators? Explain.

  • 2)

    Why are a fig tree and its partner wasp considered a good example of mutualism?

  • 3)

    How do desert lizards cope with temperature variations in their environment? Explain.

  • 4)

    Write the normal body temperature of humans.  How is it maintained during summers?

12th Standard CBSE Biology - Biotechnology and its Applications Two Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Write the function of adenosine deaminase enzyme.State the cause of ADA defeciency in humans. Mention a possible permanent cure for an ADA deficiency patient?

  • 2)

    Why is proinsulin so called? How is insulin different from it?

  • 3)

    Explain how a hereditary disease can be corrected. Give an example of the first successful attempt made towards correction of such diseases

  • 4)

    Biopiriacy should be prevented. State why and how

12th Standard CBSE Biology - Biotechnology: Principles and Processes Two Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Name the source organism from which Ti plasmid is isolated. Explain the use of this plasmid in biotechnology.

  • 2)

    How are recombinant vectors created? Why is only one type of restriction endonuclease required for creating one recombinantvector?

  • 3)

    From what you have learnt can you tell whether enzymes are bigger or DNA is bigger in molecular size? How dis you know? Explain briefly chitinase.

  • 4)

    Describe briefly origin of replication.

  • 5)

    How is the gene  z used as a marker?

CBSE 12th Biology - Microbes in Human Welfare Two Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Why is Rhizobium categorised as a 'symbiotic bacterium'? How does it act as a biofertiliser?

  • 2)

    Name the GM bacterium whose product is used as a clot buster. Name the product.Specify its used in medical science.

  • 3)

    How do methanoges help in producing biogas?

  • 4)

    Name the blank spaces a,b,c and d given in the following table:

    Type of Microbe Name Commercial Product

    Bacterium

    Fungus

       c

    Fungus

        a

        b

    Monascus purpureus

    Penicillium notatum

    Lactic acid

    Cyclosporin A

    Stain

           d

  • 5)

    How do mycorrhizal fungi help the plants harbouring them?

12th Standard CBSE Biology - Strategies for Enhancement in Food Production Two Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Explain in brief the role of animal husbandry in human welfare.

  • 2)

    Discuss the role of fishery in enhancement of food production

  • 3)

    Mention the factors responsible for the success of Green Revolution.

  • 4)

    The steps in a programme are:
    Collection of germplasm
    Crossbreeding the selected parents
    Testing, releasing and marking new cultivars.
    (i) What is this programme related to?
    (ii) Name two special qualities as basis of selection of the progeny
    (iv) What is the popular term given to this outcome? Also name the indian scientist who is credited with chalking out of this programme.

  • 5)

    What is meant by germplasm collection? Why is it necessary?

12th Standard CBSE Biology - Human Health and Disease Two Marks Questions - by Shweta Sharma - Anantapur - View & Read

  • 1)

    Name the different types of cells that are responsible for producing the acquired immune response in a human body.How do these cells respond when a pathogen enters the body?

  • 2)

    Name the two special types of lymphocytes in humans.How do they differ in their roles in immune response?

  • 3)

    What are the various public health measures,which you would suggest to safeguared us against infectious diseases?

  • 4)

    Define immunity.What are its two broad categories?

View all

CBSE Education Study Materials

12th CBSE Biology 2019 - 2020 Academic Syllabus - by Shweta Sharma - Anantapur Aug 21, 2019

Biology 2019 - 2020 Academic Syllabus

Top Tips to score high marks in CBSE Class 12 Biology - by Bala Jan 23, 2019

Biology is one subject where students need to understand the physiology of all living creatures a...

Term I Syllabus - Important Questions Model Paper In 12th Biology - by ADMIN-ENGLISH May 28, 2018

Term I Exam Syllabus Chapter Covered: Unit VI & VII The chapter that covers the Unit is Chapter-1: ...

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CBSEStudy Material - Sample Question Papers with Solutions for Class 12 Session 2020 - 2021

Latest Sample Question Papers & Study Material for class 12 session 2020 - 2021 for Subjects Physics, Chemistry, Maths, Accountancy, Introductory Micro and Macroeconomics, Business Studies, Economics, Computer Science, Geography, English, History, Indian Society, Physical Education, Sociology, Tamil, Bio Technology, Engineering Graphics, Entrepreneurship, Hindi Core, Hindi Elective, Home Science, Legal Studies, Political Science, Psychology in PDF form to free download [ available question papers ] for practice. Download QB365 Free Mobile app & get practice question papers.

More than 1000+ CBSE Syllabus Sample Question Papers & Study Material are based on actual Board question papers which help students to get an idea about the type of questions that will be asked in Class 12 Final Board Public examinations. All the Sample Papers are adhere to CBSE guidelines and its marking scheme , Question Papers & Study Material are prepared and posted by our faculty experts , teachers , tuition teachers from various schools in Tamilnadu.

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