You are here
Question
Carry out the following 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. Place each of the potato cups in a beaker containing water (Fig. 2.22). Now, set up the experiment as follows: (a) Keep Cup A empty. (b) Add one teaspoon sugar in Cup B. (c) Add one teaspoon salt in Cup C. (d) Add one teaspoon sugar in the boiled potato in Cup D. Observe the four potato cups at least two hours and answer: (i) Explain why water gathers in the hollowed portion of Cup B and Cup C. (ii) Why is Cup A necessary for this experiment? (iii) Explain why water does not gather in the hollowed portions of Cups A and D.
Show answer
Answer
Osmosis through living cells explains the results.
Explanation
- (i) Sugar and salt make the cup contents concentrated.
- (i) Water enters by osmosis through living potato cells and gathers.
- (ii) Cup A is the control, showing no movement without solute.
- (iii) Cup A has no solute; Cup D's boiled cells are dead, so no osmosis.
Osmosis needs living cells and a concentration difference.
← Back to concept: 2.2.1 Cell membrane
