ICSE Set Qa1 Year Icse Biology97 Qa1.php Biology Exam Paper for students online
Section
- II
(i)Why are capillaries thin walled? (ii)Mention two functions of the choroid coat in the eye. (iii)What is meant by gestation period? (iv)What is the effect of shivering? (v)What is meant by photolysis of water? Ans. 4 (b) (i) Capillaries are thin walled because these have to exchange the material present in blood and tissue fluid. (ii) CHOROID COAT :- Function:- It contains numerous blood vessels that supply nutrients and Oxygen(O2) to the other tissues especially of retina . It also contains pigmented cells that absorb light and prevent it from being reflected within the eyeball. (iii) Gestation period:- It is the time from conception to birth. (iv) Effect of shivering :- Heat generates and a heating effect occurs. (v) Photolysis of water :- It is the break down of water in the presence of light into Hydrogen and Oxygen(O2) in the illuminated chloroplast. 4H2O « 4 H+ + 4OH- |
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Q 5 (a) Given below is the simplified pathway of the circulatory system of man :- (i) Name the blood vessels marked 1 to 8. (ii) Name the chamber of the heart which :- 1. receives blood from '1', 2. pumps blood into blood vessel '8'. (iii) Mention two structural differences between blood vessels '7' and '2'.
(ii) (iii) Blood vessel '7'- The blood vessels
that goes from the liver to heart is known as Hepatic vein. This does not
bring blood directly to heart but forms a network of capillaries in
another organ before reaching the heart. Actually it is a part of hepatic
portal system. It carries blood from liver to inferior vena cava . Flow of
blood is slow. It has valves. Q
5 (b) |
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Q
6(b) Give
appropriate terms for the following : |
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Q
7 Explain briefly the idea contents in any five of the following
statements : (i) Oxygen given out during photosynthesis comes from water. (ii) The need to limit the size of family is more vital today than ever before. Give two reasons. (iii) Root hairs becomes flaccid , when fertilizer are added to the moist soil around it. (iv) Transplanting of seedlings to a flower bed in the evening is better than doing so in the morning. (v) In summer urine is slightly thicker than in winter . (vi) The man can live without food for a number of days but he can not survive without Oxygen for more than a few minutes. (vii) Environmental pollution is a recent problem . Do you agree ? Give two reasons to support your answer. |
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Ans.
7 (i) Yes Oxygen given out during photosynthesis comes from water.
Ruben and Kamer et. al. suspended chlorella in water having
non-radioactive heavy isotope of Oxygen instead of natural Oxygen. The
suspension was illuminated. Oxygen evolved was tested by mass
spectrometer. It was found be heavy isotope. This is possible only if
Oxygen evolved during photosynthesis comes from splitting of water. Light / Chlorophyll 6CO2 + 12H218O -------------------------- C6H12O6 + 6H2O + 618O2 (ii) To maintain the standard of life, to provide necessary resources to the family , to provide education to the children. (iii) Fertilizers act as hypersonic solution. So the root hairs become flaccid because the water from root hairs move out and their protoplasm shrinks and the root hair become flaccid. (iv) Because during morning, the rate of transpiration will be higher so there are the chances that the seedlings may become flaccid. (v) In summer due to sweating, a lot of water evaporates from the body and so in summer urine is slightly thicker than in winter. (vii) Man shows aerobic respiration and oxygen is required for the breakdown of food. So, without oxygen respiration cannot occur and brain cells will get damaged without oxygen. (vii) Yes, environmental pollution is a recent problem. Because due to industrial revolution , industries come in existence, and new means of transport like motors , cars, truck, etc. also evolved , which further lead to environmental pollution. |