The alternative to active transport is passive transport, which uses kinetic energy only to move the molecules. Passive transport can only move molecules from a region of higher concentration to lower ...

The permeability of biological membranes is a key determinant of drug pharmacokinetics. Historically, passive diffusion through the lipid bilayer portion of a biological membrane was suggested as the ...

ACTIVE transport of sodium across cell membranes is now established as one of the fundamental physiological processes of most vertebrate cells. This process probably requires some sort of carrier ...