Question

b. is the movement of molecules down a concentration gradient, from areas of high concentration to areas of low concentration. 1. what is the difference between simple diffusion and facilitated diffusion?

Explanation:

Simple diffusion occurs without the help of transport proteins and is mainly for small, non - polar molecules passing through the lipid bilayer. Facilitated diffusion uses transport proteins (carrier or channel proteins) to move molecules (usually larger or polar) down the concentration gradient.

Answer:

1. Simple diffusion doesn't use transport proteins and is for small non - polar molecules; facilitated diffusion uses transport proteins for larger or polar molecules.