transmembrane proteins and membrane transport

diffusion

transportation of small, non-polar molecules directly through the lipid bilayer

channels

multipass proteins which form transmembrane pores, through which ions or small molecules pass selectively

aquaporins

chanel proteins that allow water molecules to cross through the plasma membranes

carriers

transmembrane proteins that bind small molecules and translocate them across the membrane

active transport

membrane pumps (enzymes) utilize ATP to move ions across membranes against concentration gradients

ATPases

The membrane pumps which allow for active transportation