CBSE Class 12 Biology Sample Papers 2011 Set C

SECTION - A

1. The following statements describe the wind-pollinated plants. Which one of these statements is incorrect?

(i) The pollen grains are sticky.

(ii) Stamens are well exposed.

(iii) Flowers often have a single ovule.

2. Write 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. Give the name of the carcinogenic dye which is used to stain gel to make the DNA visible under UV light.

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

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

7. ‘Eutrophication’ is the natural aging of a lake. Mention another feature which defines this term.

8. How are standing crop and biomass related to each other?

SECTION–B

9. What do you understand by amniocentesis? Why is there a statutory ban on this? Give reason.

10. A non-haemophilic couple was informed by their doctor that there is possibility of a haemophilic child being born to them. Draw a checker board and find out the percentage of possibility of such a child among 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 is the introduction of genetically engineered lymphocytes into an ADA deficiency patient not a permanent cure? Suggest a possible permanent cure.

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