Question

How does osmosis differ from diffusion?

Answer 1

Osmosis and diffusion is the movement of molecules from the region of higher concentration to the region of lower concentration in a given medium. The movement of molecules takes place until the medium becomes homogeneous.

Complete answer:
The movement of molecules places a vital role in nature. The molecules like the solute and solvent move from one concentration to another so as to establish equilibrium. The movement of molecules takes place by several processes like osmosis and diffusion. Let us discuss the difference between the two.

Osmosis	Diffusion
Osmosis is the movement of the solvent molecules from the region of higher concentration to the region of lower concentration across a semipermeable membrane.	Diffusion is the movement of molecules(solid, liquid, gaseous) from the region of higher concentration to the region of lower concentration.
It requires a semi-permeable membrane for the movement of selective molecules.	It does not require any membrane barrier.
The direction of the movement depends on the number of solute molecules. If the solute present is more, then the solvent molecules will move towards the solution.	It depends on the presence of other particles.
The movement of particles is unidirectional.	The movement of particles can take place in all directions.
The process of osmosis can be stopped or reversed by applying force.	The process of diffusion cannot be stopped.
Example- Ion channel across the cell membrane.	Example- Oxygen produced in the photosynthesis diffuses from the plant cell to the atmosphere.

Note: The solution can be of three types-
1)Isotonic- The solution in which the concentration of solute and solvent is the same.
2)Hypotonic- The solution in which the solute concentration is less than that of solvent.
3)Hypertonic -The solution in which the solute concentration is greater than that of solvent.

Osmosis takes place from hypotonic solution to hypertonic solution till the concentration of the solvent becomes same in both the medium.