Facilitated Diffusion
Facilitated diffusion is also called carrier-mediated
diffusion
because a substance transported in this manner
diffuses through the membrane using a specific carrier
protein to help. That is, the carrier facilitates diffusion of
the substance to the other side.
Facilitated diffusion differs from simple diffusion in
the following important way: Although the rate of simple
diffusion through an open channel increases proportionately
with the concentration of the diffusing substance,