CBSE Guess > Papers > Question Papers > Class XII > 2005 > Biology > Compartment Delhi Set-I

BIOLOGY 2005 (Set I—Compartment Delhi)

SECTION - A

Q. 1. Where are the pigments forming the photosystem located in the chloroplasts? 1

Q. 2. What does “leg” in leghaemoglobin refer to? Why is this pigment called oxygen-scavenger? 1

Q. 3. Name the category of regeneration, which involves the repatterning of the whole body from small fragments. Name one animal in which it occurs. 1

Q. 4. Name the antifreeze compounds that help the fishes living in Antarctica in seawater even at temperature below 0⁰ C. 1

Q. 5. What is tissue-typing in organ transplantation in humans’? 1

SECTIONS - B

Q. 6. What is oxidative decarbxylation of pyruvic acid? When does it occur? 2

Q. 7. A person is suffering from calcium deficiency in spite of taking a calcium rich diet. Explain how this condition may have occurred. 2

Q. 8. What is chloride shift? Explain. 2

Q. 9. How are the two heart sounds produced during cardiac cycle? Which one of these is of longer duration? 2

Q. 10. Mention any two differences between auxetic growth and multiplicative growth. 2

Q. 11. Give the collective term for chemicals such as hyaluronidase and acrosin. Where are they contained? Give the function of any one of them. 2

Q. 12. Name the two basic types of competition found amongst organisms. Which one these is more intense and why? 2

Q. 13. What does the term biodiversity refer to? Mention any two factors which pose pose threat to bio-diversity. 2

Q. 14. What is acne? How is acne considered the commonest problem of almost all adolescents? 2

Q. 15. Define mutation. List the three way in which mutations can arise. 2

Or

How is mutation breeding carried out for developing crop varieties?

SECTION - C

Q. 16. What is thermal stratification in deep water bodies? Metion one advantage of autumn and spring turnover. How are organisms living in temperate takes benefited by it? 3

Q. 17. Which one gas is most abundant out of the four comment green house gases? Discuss the effect of this gas on the growth of plants. 3

Q. 18. What is a transgenic crop? State two advantage of the technique involved in the production of transgenic crop over breeding activities. 3

Q. 19. Enumerate three properties of cancer cells, which distinguish them from normal cells. 3

Q. 20. A sperm has just fertillised human egg in the fallopian tube. Trace the events that the fertillised egg will undergo up to the implantation of the blastocyst in the uterus. 3

Q. 21. Draw a diagram of the L.S. of mature angiospermic (anatropous) ovule. Label any six parts. 3

Or

Draw a diagram of the transverse section of an angiosperm another. Label any six parts.

Q. 22. How are myelinated axons more efficient than the non-myelinated axons for the conduction of nerve impulse? 3

Q. 23. Why is uricotelism considered advantageous to the vertebrates that lay shelled eggs? 3

Q. 24. What causes wilting and drooping of leaves during a hot summer after noon? Explain. 3

Q. 25. State three criteria of essentiality of an element in plant nutrition. 3

SECTION - D

Q. 26. Describe the biosynthetic Phase of photosynthesis. 5

Or

What is oxidative phosphorylation? Explain the same with the help of a flow-chart.

Q. 27. List any five hormones secreted by adenohypophysis (anterior pituitary). Mention the principal action of each hormone and its target organ. 5

Or

Name a gland in humans acting both a endocrine and exocrine, mention the three endocrine secretions from this gland giving two principal actions each secretion.

Q. 28. What is meant by Ozone shield? Name two ozone-depleting substances. Hoe are you the Ozone-depleting substances affect the ozone shield? Write one damaging effect of ozone-depletion on humans and plants repectively. 5

Or

List any four factors which determine the amount of dissolved oxygen in water. Explain in brief the harmful effects of nitrate, fluoride and arsenic salts in ground water, on humans.