Carry out the following osmosis experi ment. Take four peeled potato to halves and scoop each one out to make potato cups one of these potato cups should be made from a boiled potato. Put each potato cup in a tray containing water . Now
(a) Keep cup A empty
(b) Put one teaspoon sugar in cup B
( c) Put one teaspoon sugar in the boiled potato cup D. Keep these for two hours . The observe the four potato cups and answer the following : M
(i) Explain why water gathers in the hollowed portion of B and C .
(ii) Why is potato A necessary for the experiment .
(iii) Explain why water does not gather in the hollowed out portions of A and D.

Explanation

Water gather in the hollowed portions of set up B and C because water enters the potato as result of osmosis . Since the medium surrounding the cell has a higher water concentration than the cell the water moves inside by osmosis. Hence water gathers in the hollowed portions of the potato cup.
(ii) Potato A in the experiment acts as a control set up. No water gather in the hollowed portions of potato A .
(iii) Water does not gather in the hollowed portions of potato A because potato cup A is empty . It is a control / setup in the experiment. Water is not able to enter potato D because present in the cell membrane and thus disrupts the proteins present in the cell membrae and thus disrupts the cell membrane . For osmosis a semipermeable membrane is required which is disrupted in this case. Therefore osmosis will not occur. Hence water dose not enter the boiled potato cup.