Facilitated diffusion

Definition

Facilitated diffusion is a type of passive transport in which molecules move across the cell membrane through protein channels or carriers without the expenditure of cellular energy. It allows substances that are not able to directly pass through the lipid bilayer to enter or exit the cell based on concentration gradients.

Related terms

Passive Transport: The movement of substances across cell membranes without the need for energy input from the cell.

Protein Channels:

Protein structures embedded in cell membranes that provide passageways for molecules to travel into and out of cells.

Concentration Gradient:

The difference in the concentration of a substance between two areas, which drives substances from an area of higher concentration to an area of lower concentration during facilitated diffusion