CBSE Class 12 Biology Sample Paper 2014 Set 03

Section A 

1. If the stamens are well exposed, usually which mode of pollination the plant is expected to follow?

2. If the frequency of one allele is ‘p’ and for another, it is ‘q’ for one gene, what will be the formula to calculate allele frequency in future generations according to Hardy - Weinberg genetic equilibrium?

3. “Pranay suffered from measles at the age of 10 years. There are rare chances of his getting infected with the same disease for the rest of his life.” Give reason for the statement.

4. Why EtBr is used in gel electrophoresis inspite of it being highly carcinogenic?

5. Which main technique and instrument is used to isolate DNA from any plant cell?

6. How is the action of restriction endonucleases different from that of normal endonucleases?

7. Eutrophication is the natural aging of a lake; mention any other feature which defines this term.

8. Standing crop and biomass are related to each other, how? 

Section B 

9. What does amniocentasis test? On what basis does it work? Is it justified to put is a statutory ban on this process? Give reason.

10. A non-haemophilic couple was informed by their doctor that there is possibility of a haemophilic child be born to them. Draw a checker board and find out the percentage of possibility of such child in the progeny.

11. How do Darwin’s finches illustrate adaptive radiation?

12. In a particular plant species, majority of the plants bear purple flowers. Very few plants bear white flowers. No intermediate colours are observed. If you are given a plant bearing purple flowers, how would you ascertain that it is a pure breed for that trait? Explain. 

13. Why the introduction of genetically engineered lymphocytes into an ADA deficiency patient is not a permanent cure? Suggest a possible permanent cure.

14. Where and why do we use Taq polymerase enzyme when it works exactly as DNA polymerase?

15. Differentiate between a detrivore and a decomposer giving one example of each. 

16. DDT content in the water of a lake that supplies drinking water to the nearby villages is found to be 0.004 ppm. The pelicans of that area are reported to have 2.6 ppm of DDT. Why has the concentration increased in these birds? What possible harm can this cause to the bird population? Also give the name the phenomenon.

17. The gradual and predictable change in the species composition of a given area is called ecological succession. Define the pioneer and climax community in this context?

18. Write the biological (binomial) names of causal organisms of the following diseases:

a) Typhoid

b) Pneumonia

OR

Write the biological (binomial) names of causal organisms of the following

diseases:

a) Elephantiatis (Filariasis)

b) Amoebiasis

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