Osmosis vs Diffusion – Difference and Comparison

What is Osmosis?

Osmosis is a process that occurs at the cellular level. They involve the movement of water molecules from an area of high water concentration to an area of low water concentration.

Water travels from a high-water concentration location to a low-water concentration area through osmosis. In other words, osmosis is the diffusion of water.

Osmosis is a vital process in the human body. They help to regulate cell hydration, which is essential for many cellular processes. A semipermeable membrane is one that enables only certain molecules to pass through.

When water molecules move from an area of high concentration to an area of low concentration, this is known as moving from a hypotonic solution to a hypertonic solution.

Osmosis is a passive process that requires no energy from the cell. They allow only water molecules to pass through.

What is Diffusion?

Diffusion is the process by which molecules move from an area of high concentration to an area of low concentration.

The process is driven by the tendency of molecules to move from areas of higher energy to areas of lower energy. They occur in the lungs. 

Oxygen diffuses from the air into the blood and into the kidneys, whereas waste products diffuse from the blood into the urine. This process is responsible for the transport of oxygen, carbon dioxide, and water.

Diffusion is a vital process that helps to maintain homeostasis in the body. They are used to transport materials through membranes, as well as mix different substances.

For example, if there is an area with a high concentration of a molecule within the body, diffusion will help to spread that molecule out so that its concentration becomes more equal to the surrounding areas. Diffusion can be passive or active.

Difference Between Osmosis and Diffusion

The main difference between osmosis and diffusion is:

Osmosis is the movement of water through a semipermeable membrane. Diffusion is the movement of molecules from an area of high concentration to an area of low concentration.

Osmosis is driven by the difference in water potential. Diffusion is driven by the difference in chemical potential

Osmosis is a passive process, while diffusion is an active process. Osmosis occurs across a semi-permeable membrane. Diffusion can occur across any type of membrane.

Comparison Between Osmosis and Diffusion

Parameters of comparison  OsmosisDiffusion  
MediumIt is only available in medium.It can be found in liquids, gases, and even solids.
Semipermeable membraneA semipermeable membrane is required.It is not necessary to use a semipermeable membrane.
Number of particlesThis is determined by the number of solute particles dissolved in the solvent.It is affected by the presence of other particles.
Water requiredWater is required for particle mobility.Water is not required for particle movement.
Diffuse moleculeA solvent molecule can only diffuse.Solvents and solvent molecules can both diffuse.
DirectionParticles can only move in one direction.The movement of particles occurs in all directions.
ProcedureThe procedure can be interrupted or reversed.This procedure cannot be interrupted or reversed.
Types of solutionsThese occur between solutions of similar kinds.This happens between solutions that are similar and ones that are dissimilar.
Mineral and absorptionIt has nothing to do with mineral and nutritional absorption.It promotes mineral and nutrient absorption.


  1. https://www.sciencedirect.com/science/article/pii/S0376738806003838
  2. https://academic.oup.com/qje/article-abstract/124/2/469/1905073