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 one mark each. Answer them in 1-20 words each.

Question 1. Name the process in which bacteriophage picks-up a piece of DNA from one bacterial cell and transfers the same to another bacterial cell on infection.

Question 2. Which fraction of soil water is readily available to plants for absorption?

Question 3. What protects nitrogenase?

Question 4. Name two plants that produce rhizomes.

Question 5. Why is oxytocin called as ‘Birth Hormone’?

Question 6. From which germ layers do the following organs differentiate :

(i) Kidney

(ii) Urinary bladder

Question 7. What provides energy for abiotic synthesis on the primitive earth?

Question 8. Name the two curable sexually transmitted diseases.

Section B

Q. Nos. 9-18 are short answer questions carrying 2 marks each.It is appropriate to answer them in about 20-30 words.

Question 9. In most plants the terminal bud suppresses the development of lateral buds. What is this phenomenon called? Name the phytohormone that can promote the phenomenon.

Question 10. Sieve tubes in angiosperms are associated with specialised parenchyma cells. Name those cells. How do they help sieve tube members?

Question 11. How is the digested fat absorbed?

Question 12. What are antagonistic muscles? Give one example.

Question 13. Describe the methods of birth control by which fertilisation of ovum by sperm is prevented.

Question 14. What is artificial selection in terms of evolution? Name one plant that has been produced as a result of artificial selection.

Question 15. ‘Birds have evolved from reptiles’. How does palaentology provide evidence in support of the above statement?

Question 16. Who discovered the coacervates? List the biological properties of co-acervates.

Question 17. What is mycorrhiza? How does it act as biofertiliser?

Question 18. Define autoimmune diseases. Give two examples.

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