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Question : 9
Total: 10
(a) A gas is released during photosynthesis. Name the gas and also state the way by which the gas is evolved.
(b) What are stomata ? What governs the opening and closing of stomata ?
OR
(a) Draw a diagram of human alimentary canal and label - gall bladder, pancreas, liver and small intestine on it.
(b) Give two reasons to explain why absorption of digested food occurs mainly in the small intestine.
(b) What are stomata ? What governs the opening and closing of stomata ?
OR
(a) Draw a diagram of human alimentary canal and label - gall bladder, pancreas, liver and small intestine on it.
(b) Give two reasons to explain why absorption of digested food occurs mainly in the small intestine.
Solution:
Oxygen gas is released during the process of photosynthesis. Carbon dioxide and water present in the air takes the light energy from the sun and in the presence of the chlorophyll pigment converts the CO 2 H 2 O
The reaction of photosynthesis is as follows:6 CO 2 + 6 H 2 O → C 6 H 12 O 6 + 6 O 2
The oxygen during the process of photosynthesis mainly comes from the splitting of the water molecule in the presence of the sunlight and during the process of photosynthesis the plants absorb water and carbon dioxide. The excess oxygen gathered is released into the atmosphere which is utilised by the humans for the breathing.
(b) The small openings or pores on the lower surface of the leaves are called stomata. Stomatal pores in plants regulate the amount of water and solutes within them by opening and closing their guard cells using osmotic pressure. In order for plants to produce energy and maintain cellular respiration. The exchange of the gases occurs across the surface of the stems, roots and leaves as well. Also the large amount of water can also be lost through the stomata, thus to prevent this the plant closes these pores when carbon dioxide is not needed for photosynthesis. The opening and closing of the pores is the function of the guard cells. The guard cells swell when water flows into them, causing the stomatal pore to open similarly the pore closes if the guard cells shrink. The opening and closing of stomata is regulated by the guard cells can be depicted diagrammatically as follows :
OR
(i) Digestion is completed in the small intestine because the inner lining of the small intestine is provided with villi which increase the surface area for absorption of digested food.
(ii) Villi of the intestine is richly supplied with blood vessels which assimilate the absorbed food to the other parts of the body.
The reaction of photosynthesis is as follows:
The oxygen during the process of photosynthesis mainly comes from the splitting of the water molecule in the presence of the sunlight and during the process of photosynthesis the plants absorb water and carbon dioxide. The excess oxygen gathered is released into the atmosphere which is utilised by the humans for the breathing.
(b) The small openings or pores on the lower surface of the leaves are called stomata. Stomatal pores in plants regulate the amount of water and solutes within them by opening and closing their guard cells using osmotic pressure. In order for plants to produce energy and maintain cellular respiration. The exchange of the gases occurs across the surface of the stems, roots and leaves as well. Also the large amount of water can also be lost through the stomata, thus to prevent this the plant closes these pores when carbon dioxide is not needed for photosynthesis. The opening and closing of the pores is the function of the guard cells. The guard cells swell when water flows into them, causing the stomatal pore to open similarly the pore closes if the guard cells shrink. The opening and closing of stomata is regulated by the guard cells can be depicted diagrammatically as follows :
OR
(b) The small intestine is the most important part of the digestive system. Maximum absorption occurs in the small intestine because of the following reasons:
(i) Digestion is completed in the small intestine because the inner lining of the small intestine is provided with villi which increase the surface area for absorption of digested food.
(ii) Villi of the intestine is richly supplied with blood vessels which assimilate the absorbed food to the other parts of the body.
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