Question

How does a living cell behave in hypotonic and isotonic solutions?

Answer 1

Tonicity of solutions:

1. Hypotonic solution is the solution that has a lower solute concentration (more water molecules) and lower osmotic pressure than the solution from which it is separated through a semipermeable membrane.
2. Isotonic solution is the solution that has the same water concentration as inside the cell, so there will be no osmotic pressure.

Effect of tonicity of solutions on the living cell:

Condition 1: If a cell is placed in a hypotonic solution

• There will be inward movement of water molecules across the semipermeable membrane.
• The inward movement of water molecules through a semi-permeable membrane is known as endosmosis. This will result in swelling of the cell (turgid cell).

Condition 2: If a cell is placed in an isotonic solution:

• In this condition, the water concentration of the surrounding solution and the cell is the same.
• As a result, there will no net movement of water molecules across the semi-permeable membrane.