Question

Water potential of a cell , when it is placed in a hypotonic solution
A. Decrease
B. Increase
C. First increase then decrease
D. No change

Answer 1

Hint: Water potential is the tendency of water to move from one part to the other during various cellular processes like diffusion, osmosis etc. water potential is represented by Greek word Ψ(psi) and it is measured in bars or pascals.

Complete Answer:
- Highest water potential occurs in pure water. It is always 0 at standard temperature and pressure. When water is in liquid form the movement of its molecule is rapid and constant. The pure ware has the highest concentration of water molecules.
- Therefore, it has the highest water potential. When some solute dissolved in water the water potential of pure water decreases.
- Highest solution concentration is found in hypotonic solution. So the water molecules move out from the cell through osmosis.
- When water leaves the cell the concentration is increasing and the water potential decreases.

Hence from the given options a option is correct.

Additional information:
- Diffusion is the process of passive movement of molecules,ions and particles along the concentration gradient. It can occur in solid liquid and gases. It does not require a semipermeable membrane.
- Osmosis is the process in which the diffusion of solvent occurs across the semipermeable membrane. It occurs only in liquid medium. It requires a semipermeable membrane.

Note: A solution having low osmotic concentration as compared to another solution is known as hypotonic solution. A solution having high osmotic concentration as compared to another solution is termed as hypertonic solution.