CBSE Guess > Papers > Question Papers > Class XII > 2005 > Biology > Outside Delhi Set-II

BIOLOGY 2005 (Set II—Outside Delhi)

Except for the following questions all the remaining questions have been asked in Set I.

SECFION - A

Q. 1. What is a model in mimicry? 1

Q. 2. Why is Hydra said to be virtually immortal? 1

Q. 3. Drosera carres out photosynthesis and still traps insects. Why? 1

Q. 4. What is the total number of bones present in the left pectoral girdle and the left arm respectively in a normal human ? 1

Q. 5. How does Colchicine induce polyploidy? 1

SECI’ION - B

Q. 6. What is accretlonary growth? Give one example. 2

Q. 7. An Rh-negative mother has safely delivered her first Rh-positive child. Discuss the problems that can arise as a result of it and can affect a subsequent pregnancy. 2

Q. 8. Describe the function of phosphofructokinase in glycolysis.

Q. 11. How are fungal pathogens disseminated from one plant to another? Give two symptoms of fungal infections in plants. 2

Q. 12. Why do temperate regions show a tower value of primary productivity as compared to tropical regions ? Give two reasons. 2

Q. 13. What is the end product of glycolysis in aerobes, and where does this pro- cess occur? List the conditions under which fermentation occurs in plant cells. 2

Or

Where exactly does electron transport system operate in Mitochondria? What is the role of oxygen and F0 — F1 in this pathway? How many molecules of ATP are produced when one molecule of NADH goes through this path?

Q. 14. Name the disorders caused due to undersecretion and oversecretion of in- sulin respectively in humans. Mention their symptoms. 2

Q. 15. Explain symbiotic nitrogen fixation in leguminous plants. 2

SECTION - C

Q. 17. In what form is Boron absorbed by plants from the soil? Mention its two uses in the plants and give two deficiency symptoms of Boron in them. 3

Q. 20. Distinguish between Alpha and Beta diversity in an ecosystem. What is the significance of large genetic diversity in a population? 3

Or

What are Algal Blooms? How are they formed? Give two harmful effects of formation of Algal Blooms in an aquatic body.

Q. 23. Name one enzyme of gastric juice and one of pancreatic juice that are released as proenzymes in the human alimentary canal Give the substrate and the end products of each. 3

Q. 24. Differentiate between quiescent and dormant seeds. Give any four reasons why some seeds need to undergo dormancy. 3

Q. 25. What are the two intrinsic mechanisms that provide autoregulation of glomerular filtrate? Explain any one of these. 3

SECTION – D

Q. 26. Distinguish between Natural and Artificial Pacemaker of the human heart. Explain the events that occur in the human heart during ventricular systole and ventricular diastole in a single cardiac cycle. 5

Or

Explain how the respiratory gases are transported in the human body.

Q. 27. Explain the mechanism of closing and opening of stomata. Name the cat- egory of plants which keep their stomata open during the night and closed during the day. 5
Or
Explain the mechanism of C4 photosynthetic carbon cycle. Name any two plants where it occurs. Mention the difference in the structure of chloroplasts in the mesophyll cells and bundle sheath cells in such plants.

Q. 28. Draw labelled diagrams of the following:
a) T.S. of bibbed anther of an angiosperm
b) Internal structure of a pollen grain of an angiosperm 5
Or
Draw a flow-chart showing hormonal control of human female reproductive system. Highlight the positive and negative feedback mechanism in it.