Biology Class XII

You are on questions of Section A,B,C,D

Max. Marks : 70

Time allowed : 3 hrs

Section - A

Q.Nos. 1-8 are of very short answer type carrying 1 mark each. Answer them in one word/one sentence having 1-20 words each.

Question 1. What is meant by trisomic condition?

Question 2. State the presence or absence of sinus venous in a fish and a mammal.

Question 3. Which type of cartilage is present between vertebrae to allow limited movement?

Question 4. Name any two breeds of wild rock pigeon that have been developed through artificial selection. 1 mark Q 5. Which chromosomes are called autosomes?

Question 6. When is a tumour referred to as malignant?

Question 7. What are the two factors that contribute for the dissociation of oxyhaemoglobin in the arterial blood to release molecular oxygen in an active tissue?

Question 8. Which one of the following is fatal unless oral rehydration therapy is administered:

(i) Whooping cough

(ii) Cholera

(iii) Tetanus

Section B

Q. Nos. 9-18 are of short answer type carrying 2 marks each. Answer them in approximately 20-30 words each.

Question 9. What are the two functions of DNA polymerase?

Question 10. Stanley Miller and Harold C. Urey performed an experiment by recreating in the laboratory the probable conditions of the atmosphere of the primitive earth.

(i) What was the purpose of the experiment?

(ii) In what forms was the energy supplied for the chemical reactions to occur?

(iii) For how long was the experiment run continuously?

Question 11. How does the mustard inflorescence differ from the banana inflorescence in arrangement? Give the technical term for each.

Question 12. Name the basic nitrogenous catabolite of proteins produced in birds. In what form is it eliminated from their body? What is the advantage of this type of excretion?

Question 13. Describe the theory of inheritance of acquired characters. Who disproved it experimentally?

Question 14. Differentiate between morula and blastula of mammals.

Question 15. What is the biological significance of Azolla pinnate in agriculture?

Question 16. Give any two reasons to justify that ginger is a modified stem.

Question 17. Define biogeography. How do Darwin's Finches provide the biogeographical evidence in favour of evolution?

Question 18. Explain the structural and functional significance of fovea in the human eye.