Question

A plant cell placed in pure water will

• A. expand until the osmotic potential or solute potential reaches that of water.
• B. becomes more turgid until the pressure potential of cell reaches its osmotic potential.
• C. become more turgid until the osmotic potential reaches that of pure water.
• D. becomes less turgid until the osmotic potential reaches that of pure water.

Answer 1

Answer: (B)

Plant cells are enclosed by a rigid cell wall. When the plant cell is placed in a hypotonic solution, it takes up water by osmosis and starts to swell, but the cell wall prevents it from bursting. The plant cell is said to have become "turgid" i.e. swollen and hard. The pressure inside the cell rises until this internal pressure is equal to the pressure outside. This liquid or hydrostatic pressure called the turgor pressure prevents further net intake of water. So the correct answer is 'becomes more turgid until the pressure potential of the cell reaches its osmotic potential'.