Osmosis is a passive transport process that occurs across a semi-permeable membrane from a region of high water concentration to a region of low water concentration.


Osmosis is driven by the concentration gradient of water across the membrane. The concentration gradient exists due to the presence of solutes on one side of the membrane. Water molecules move from an area of low solute concentration to an area of high solute concentration to equalize the concentration of solutes on both sides of the membrane. This movement of water molecules is known as osmosis.


Several factors affect the rate and direction of osmosis, including:

• Concentration gradient: The greater the difference in solute concentration between the two sides of the membrane, the faster the rate of osmosis.


• Temperature: An increase in temperature increases the rate of osmosis due to the increased kinetic energy of the water molecules.


• Pressure: An increase in pressure on the side with the higher solute concentration can slow or reverse the direction of osmosis.


• Membrane permeability: The rate of osmosis is affected by the permeability of the membrane to water and solutes.

Osmotic pressure refers to the pressure that must be applied to the side with the higher solute concentration to stop the movement of water molecules. The greater the concentration gradient, the higher the osmotic pressure.


Osmosis has several practical applications, including:

• Water purification: Reverse osmosis is used to remove impurities from water.


• Food preservation: Osmosis is used to preserve food by dehydrating it.


• Medical applications: Osmosis is used in dialysis to remove waste products from the blood.

Movement of water molecules from higher concentration to lower concentration is called osmosis