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Diffusion vs. Osmosis: Understanding the Differences

May 30, 2023
written by Sidra Batool

The main difference between diffusion and osmosis is that diffusion is the movement of particles from high to low concentration, while osmosis is the movement of solvent molecules to equalize concentration through a semipermeable membrane.

image showing Difference Between Diffusion and Osmosis

Diffusion vs. Osmosis

Here are the main Differences Between Diffusion and Osmosis:

FactorsDiffusionOsmosis
DefinitionThe movement of particles (solutes) from an area of high concentration to an area of low concentration until equilibrium is reachedThe movement of water molecules across a selectively permeable membrane from an area of low solute concentration to an area of high solute concentration
NatureCan involve the movement of any type of particles (solutes), including gases, liquids, and solidsSpecifically refers to the movement of water molecules
Driving ForceConcentration gradient (difference in solute concentration)Difference in solute concentration (osmotic gradient)
MembraneCan occur through any type of membrane, including cell membranes and artificial barriersOccurs specifically through a selectively permeable membrane
DirectionOccurs in all directions, from areas of high concentration to areas of low concentration until equilibrium is reachedSpecifically occurs in the direction of higher solute concentration
Role in Living SystemsEssential for various biological processes, including nutrient absorption, gas exchange, and waste removalVital for maintaining water balance in cells and tissues, osmoregulation, and maintaining cell shape
ExamplesPassive diffusion of oxygen and carbon dioxide across lung membranesMovement of water into plant roots from the soil
DependencyNot dependent on the presence of a solventRequires the presence of a solvent, typically water