Concentration gradient

Definition

A concentration gradient exists when there is a difference in the concentration of molecules across a distance, such as across a cell membrane. This gradient drives the diffusion of substances from an area of higher concentration to an area of lower concentration until equilibrium is reached.

Related terms

Diffusion:

The passive movement of molecules or particles along a concentration gradient, from areas of high concentration to areas of low concentration.

Osmosis:

The movement of water molecules through a semipermeable membrane from an area of low solute concentration to an area of high solute concentration.

Cell Membrane:

A biological membrane that separates the interior of all cells from the outside environment and controls the movement of substances in and out of cells