In comparing simple diffusion to facilitated diffusion, you note that _.
A) both require ATP
B) both require a specific carrier or protein channel
C) both can move substances up, as well as down, a concentration gradient
D) both require a concentration gradient

Question

Quizplus · Accepted Answer

Both simple and facilitated diffusion rely on a concentration gradient to move substances from an area of higher concentration to an area of lower concentration, without the use of ATP. Simple diffusion does not require a specific carrier or protein channel, while facilitated diffusion does. Neither can move substances up a concentration gradient.

In Comparing Simple Diffusion to Facilitated Diffusion, You Note That