Question

Define Osmosis. What are the different types of osmosis? Give examples. [5 MARKS]

Answer 1

Definition: 2 Marks
Naming : 2 Marks
Examples :1 Mark

Osmosis:

1. Osmosis is diffusion of water or solvent through a semi-permeable membrane from the region of lower solute concentration to that of higher solute concentration, i.e., down the concentration gradient.
2. This involves the passage of water across a selectively permeable membrane, from a region of high water concentration to a region of low water concentration.
3. Osmosis is also a passive transport as no external energy is required.
4. There are two type of osmosis:

• Endosmosis : The process in which the water molecules enter into the cell.
• Exosmosis : The process in which the water molecules move out of the cell.
• Examples of Osmosis are :

1. Absorption of water by plant roots.
2. Absorption of water by alimentary canal.
3. Re-absorption of water by tubules of the nephron in the kidneys.