key term - Semipermeable membrane

Definition

A semipermeable membrane is a type of biological or synthetic membrane that allows certain molecules or ions to pass through while restricting the passage of others.

Related terms

Diffusion:

The passive movement of molecules from an area of higher concentration to an area of lower concentration.

Osmosis:

The diffusion of water across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Active Transport:

The movement of ions or molecules across a cell membrane against their concentration gradient, requiring energy in the form of ATP.