Question

Carry out the following osmosis experiment:

Take four peeled potato 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 trough containing water. Now,

(a) Keep cup A empty.
(b) Put one teaspoon sugar in cup B.
(c) Put one teaspoon salt in cup C.
(d) Put one teaspoon sugar in the boiled potato cup D.

Keep these 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 portions of A and D.

Answer 1

(i) Since sugar and salt was present in B and C respectively, water from the trough gathered in the hollowed portions of potato in B and C by the process of osmosis.
(ii) Potato A is necessary for carrying out this experiment because it acts as a control experiment. Control helps us to check what changes occurred during the course of the experiment and helps us to compare the results.
(iii) Water does not gather in the hollowed portion of potato A as it was empty. Water also does not gather in the cup D because the potato used was boiled which makes it inactive as after boiling its protein structure were denatured, resulting in the disruption of the cell membrane.