Compare and contrast facilitated diffusion and osmosis.

Facilitated diffusion is the process whereby substances are move down a concentration gradient, from a region of high concentration to a region of low concentration, using a protein as a carrier or a channel. Active transport is the process whereby substances are moved up a concentration gradient, from a region of low concentration to a region of high concentration, using a protein as a carrier or channel. Facilitated diffusion is a passive process, so no energy is required whereas active transport is an active process, requiring energy from ATP. Both process require a protein to act as a carrier or channel to move the substances.