Question

Differentiate between members of each of the following pairs with reference to the phrases in brackets.

1. Osmosis and diffusion (flow of solvent molecules).

Answer 1

Diffusion:

Diffusion is defined as the main means of transport of substances or molecules from a region of higher concentration to a region of lower concentration.

Osmosis:

Osmosis is the passage of solvent molecules across a semipermeable membrane from a region of high water potential towards a region of low water potential.

Diffusion	Osmosis
1. Diffusion involves the movement of both solute and solvent molecules along the concentration gradient.	1. Osmosis involves the movement of only solvent molecules along the concentration gradient of solvent.
2. It does not involve a semipermeable membrane.	2. It involves a semipermeable membrane.
3. The flow of molecules can occur in all directions.	3. The flow of solvent molecules can only occur in a specific direction.
4. Significance of diffusion: transpiration of water in form of water vapor, gaseous exchange by respiration, etc.	4. Significance of osmosis: absorption of water molecules by roots, opening and closing of stomata, etc.