Science (English Medium) Class 12 - CBSE Question Bank Solutions

Name and describe the technique that helps in separating the DNA fragments formed by the use of restriction endonuclease

Explain, giving three reasons, why tropics show greatest levels of species diversity.

In which way have microbes played a major role in controlling diseases caused by harmful bacteria?

Name any two species of fungus, which are used in the production of the antibiotics.

Find out the name of the microbes from which cyclosporin A (an immunosuppressive drug) and statins (blood cholesterol lowering agents) are obtained.

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

Make a chart (with diagrammatic representation) showing a restriction enzyme, the substrate DNA on which it acts, the site at which it cuts DNA and the product it produces.

Do eukaryotic cells have restriction endonucleases? Justify your answer.

Collect 5 examples of palindromic DNA sequences. Better try to create a palindromic sequence by following base-pair rules.

Explain briefly:

Restriction enzymes and DNA

Distinguish between exonuclease and endonuclease.

List the attributes that populations but not individuals possess.

If a population growing exponentially double in size in 3 years, what is the intrinsic rate of increase (r) of the population?

Give three hypotheses for explaining why tropics show greatest levels of species richness.

What is the significance of the slope of regression in a species-area relationship?

What initiatives were taken for reducing vehicular air pollution in Delhi? Has air quality improved in Delhi?

What role does an individual organism play as per Darwin's theory of natural selection?

Describe the structure of a nucleosome.

Mention the evolutionary significance of the Shrews

Mention the evolutionary significance of the Lobefins