Difference between Osmosis and Diffusion

Osmosis and diffusion are the two different types of passive transport which play an important role in moving molecules in and out of the cell.


The process of moving of solvent particles across a semipermeable membrane from a dilute solution into a concentrated solution to equalize concentration. The complete process does not require energy in order to take place.

For example, The absorption of water molecules from the soil through the roots of the plant.

More to Explore: Reverse Osmosis


The process of moving particles from a region of higher concentration to the region of lower concentration until equilibrium is reached. The complete process does not require energy in order to take place.

For example, The diffusion of the perfume sprays into the air by spreading the aroma.

Difference between Osmosis and Diffusion

Osmosis Diffusion
It is limited only to the liquid medium. Occurs in all mediums – Solid, Liquid and gas.
Requires a semipermeable membrane. Do not require a semipermeable membrane.
Depends on the number of solute particles dissolved in the solvent. Depends on the presence of other particles.
Requires water for the movement of particles. Do not require water for the movement of particles.
Only the solvent molecules can diffuse. Both the molecules of solute and solvent can diffuse.
The flow of particles occurs only in one direction. The flow of particles occurs in all the directions.
The entire process can either be stopped or reversed by applying additional pressure on the solution side. This process can neither be stopped nor reversed.
Occurs only between similar types of solutions. Occurs between the similar and dissimilar types of solutions.
It involves the movement of only solvent molecules from one side to the other. It involves the movement of all the particles from one region to the other.
The concentration of the solvent does not become equal on both sides of the membrane. The concentration of the diffusion substance equalizes to fill the available space.
Depends on solute potential. Does not depend on solute potential, pressure potential, or water potential.
Only water or another solvent moves from a region of high energy or concentration to a region of lower energy or concentration. Any type of substance moves from area of highest energy or concentration to region of lowest energy or concentration.
Not associated with uptake of minerals and nutrients. It helps in the uptake of minerals and nutrients.
Evaporation is not controlled by any such process. Transpiration is controlled by the processes, such as osmotic potential and water potential.
Evaporation provides dryness to the free surface. Transpiration makes the surface of leaves and young stems wet and protects them from sunburn.

Further Reading: Cell Wall

To know more about the Osmosis and Diffusion, explore BYJU’S


To incorporate the movement of molecules in and out of the cell, two types of transport systems exist, namely osmosis and diffusion. These two systems are passive transport systems as they do not require any additional energy to function. The primary differentiating factor between the two systems is the medium in which they are employed. Osmosis can only function in a liquid medium, but diffusion can occur in all three mediums (solid, liquid and gas). Furthermore, osmosis requires a semi-permeable membrane while diffusion does not. The intake of water in plants is an example of osmosis. Diffusion is observed when a drop of food colouring is added to a glass of water, where eventually, the entire water content becomes coloured.

Extended Reading: Passive Transport



Practise This Question

The plants are attached to the soil by the structures known as____.