Simple Diffusion: molecules move across the membrane unaided
Facilitated Diffusion: molecules move across the membrane through protein channels
What is the basic difference between simple diffusion and facilitated diffusion across a cell membrane?
a) In facilitated diffusion, molecules only move with the aid of a protein in the membrane.
b) In simple diffusion, molecules move down the concentration gradient but in facilitated diffusion molecules move up the concentration gradient.
c) Simple diffusion is passive but facilitated diffusion is an active process that uses energy.
d) Simple diffusion requires molecules to move through special doorways in the cell membrane.