External fertilization occurs in majority of

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

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

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

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?

If Meselson and Stahl's experiment is continued for four generations in bacteria, the ratio of 15_N/15_N :15_N/14_N : 14N/14_N containing DNA in the fourth generation would be:

The turtle and tortoise evolved from

Which one of the following cannot be used for preparation of vaccines against plague?

Name the cytologist who cultured anthers for the first time.

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

Significance of 'heat-shock' method in bacterial transformations is to facilitate:

Which of the following combinations of risk are associated with genetically modified food?
I. Toxicity
II. Allergic reaction
III. Antibiotic resistance in micro-organisms present in the alimentary canal.

Cuscuta is an example of 

Which of the following fixes atmospheric N₂ ?

Which of the following disease is related to cadmium pollution?

The term alpha diversity refers to

Write a note on the need and significance of pollination in plants.

(a) Where do the signals for parturition originate from in humans?
(b)Why is it important to feed the newborn babies on colostrum?

Generally it has been seen that male refuses for vasectomy. As they think that it will affect their health and strength. What will you do in that condition?

Define Genome, Gene pool, Factors, Punnett square.

Why does hnRNA need to undergo splicing ? Where does splicing occur in the cell ?

Convergent evolution leads to analogous structures. Explain with the help of an example.

List a few features that characterise AIDS

Give a brief account of cultivation of sugarcane and millets.

Why are cyanobacteria considered useful in paddy fields?

A foreign DNA fragment is introduced into the plasmid at the ‘Bam H-1’ site of the tetracycline resistant gene in the vector ‘pBR 322’.
a) How does it affect the recombinant plasmid?
b) What is this mechanism known as?
c) Mention its advantages?

Name the insect pest that is killed by the product of cry IAc gene.

List the different kinds of plant communities.

Distinguish between primary and secondary productivity.

Name any four regions in India, where sacred groves are found.

List some of the waste which is generated at home. Which of them can you avoid or reduce easily?

Select out any four animals to demonstrate examples of bisexual organism:
Frog, Earthworm, Cockroach, Spider, Sponge, tapeworm, leech, honey, bee, Rat, Rabbit, House fly.

Write the name of pollinating agent and mode of pollination.

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?

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

A couple with normal vision bear a colorblind child. Workout a cross to show how it is possible and mention the sex of the affected child.

Name the type of linkage between
(i) Nitrogen base and pentose sugar
(ii) Pentose sugar and phosphate
(iii) Twoadjacent nucleotides
(iv) N-bases of both the strands of DNA

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

Write the scientific name of the pathogen that causes amoebic dysentery.Enumerate four symptoms of the disease.How is the disease transmitted?

(a) Name the tropical sugar cane variety grown in South India. How has it helped in improving the sugar cane quality grown in North India?
(b) Identify 'a', 'b' and 'c' in the following table:

Explain how are microbes important for humans.

A vector is engineered with three features which facilitate its cloning within the host cell. List the three features and explain each one of them.

Name the nematode that damages the roots of tobacco plants. How is a transgenic tobacco plant made resistant to nematode using biotechnology?

"Man can be primary as well as secondary consumer". Justify this statement.

Many plant and animal species are on the verge of their extinction because of loss of forest land by indiscriminate use by the humans. As biology student what method would you suggest along with its advantages that can protect such threatened species from getting extinct?

Though the conflict between humans and wildlife started with the evolution of man, the intensity of conflict has increased due to the activities of modern man. Justify your answer with suitable examples.

Rose plants produce large, attractive bisexual flowers but they seldom produce fruits. On the other hand Lady's finger produces plenty of fruits. Analyse the reasons for failure of fruit formation in rose.

List at least five flowers of ornamental value that are commonly cultivated at homes and in gardens. List out the names of five more flowers that are used in social and cultural celebrations in your family.

Define cleavage. Write down its characteristics.

Differentiate natality rate and mortality rate.

A snapdragon plant homozygous for red flower when  crossed with a white flowered plant of the same species produced pink flowers in F₁ generation.
(A) what is this phenotypic expression called?
(B) work out the cross to show the F₂ generation when F₁ was self pollinated.Give the phenotypic and genotypic ratios of F₂ generation.C
(C)How do you compare the F₂ phenotypic and genotypic ratios with those of Mendelian monohybrid F₂ ratio?

(i) Explain the process of DNA replication with the help of a schematic diagram.
(ii) In which phase of the cell does rep[lication occur in eukaryotes?What would happen if cell division is not followed after DNA replication?

Describe the origin of first cells from the coacervates.

How are the withdrawal symptoms of drugs managed by a physician?

Write notes on (i) Single cell protein (ii) Titipotency.

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

For selection of recombinants, insertional inactivation of antibiotic marker had been superceded by insertional inactivation of a marker gene coding for a chromogenic substrate. Give reasons.

List the disadvantages of insulin obtained from the pancreas of slaughtered cows and pigs.

What is competition? Why it is not true always? Explain competitive release and Gause's competitive exclusive principle. Write contribution of Mac Arthur.

Give an account of energy flow in an ecosystem.

Describe various devices used to remove particulate matters from air.

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