Diffusion, Osmosis and Active Transport

Diffusion

The movement of molecules from an area of greater concentration to an area of lower concentration. Does not require energy.

Osmosis

The movement of water across a semi-permeable membrane through diffusion.

Passive Transport

The movement of molecules (matter) from an area of high concentration to an area of low concentration; does NOT require energy. Diffusion is a kind of passive transport.

Equilibrium

A system in which things become equal; all particles (molecules or matter) become equal

Active Transport

The movement of substances into/out of cell through the membrane, against the concentration gradient (from low to high). Requires ATP.

solute

Substance dissolved in a solution

solvent

Substance in which something is dissolved - often WATER

Surface area

The amount of surface of the object that touches the outside world

concentration gradient

Difference in concentration of a substance from one place to another.