Question.
Carry out the following osmosis experiment. Take four peeled potato halves and hollow each one out to make potato cups. One of these potato cups should be made from the boiled potato. Put each potato cup in the trough containing water. Now (a) Keep cup A empty. (b) Put one tea spoon sugar in cup B. (c) Put one tea spoon of salt in cup C. (d) Put one tea spoon sugar in boiled cup D. Keep this set up for two hours. Then observe the four potato cups and answer the following:
(i) Explain why water gathers in the hollowed portion of B and C.
(ii) Why is potato A necessary for this experiment.
(iii) Explain why water does not gather in the hollowed out portion of A and D.
Carry out the following osmosis experiment. Take four peeled potato halves and hollow each one out to make potato cups. One of these potato cups should be made from the boiled potato. Put each potato cup in the trough containing water. Now (a) Keep cup A empty. (b) Put one tea spoon sugar in cup B. (c) Put one tea spoon of salt in cup C. (d) Put one tea spoon sugar in boiled cup D. Keep this set up for two hours. Then observe the four potato cups and answer the following:
(i) Explain why water gathers in the hollowed portion of B and C.
(ii) Why is potato A necessary for this experiment.
(iii) Explain why water does not gather in the hollowed out portion of A and D.
Solution:
(i) Sugar and salt increase osmotic concentration which results in passage of water osmoti cally from the trough through the cells of potato into its cavity.
(ii) Potato A functions as control experiment which indicates that the cavity of potato does not induce movement of water.
(iii) Water does not gather in the hollowed out portion of A because it does not have a higher osmotic concentration than the cells of potato tuber. Potato tuber D does not have living cells. Osmosis does not occur in dead cells. Therefore, despite presence of sugar in the cavity of D. no water passes from through dead potato cells into cavity of the tuber.
(i) Sugar and salt increase osmotic concentration which results in passage of water osmoti cally from the trough through the cells of potato into its cavity.
(ii) Potato A functions as control experiment which indicates that the cavity of potato does not induce movement of water.
(iii) Water does not gather in the hollowed out portion of A because it does not have a higher osmotic concentration than the cells of potato tuber. Potato tuber D does not have living cells. Osmosis does not occur in dead cells. Therefore, despite presence of sugar in the cavity of D. no water passes from through dead potato cells into cavity of the tuber.
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