Structural Organisation and Function of Cell Surface Membranes

Abstract

The surface membrane of a cell can be regarded as a phase boundary whose fundamental function is protective with respect to maintaining a fairly constant intracellular environment despite changes taking place in the external milieu. This membrane, whilst permitting selective communication between the interior of the cell and the outside medium, also controls the cell’s osmotic, electrical and chemical properties within a narrow range commensurate with the cell’s requirements for full metabolic integrity and functional competence. All of these properties depend heavily upon selective transport processes associated with the surface membrane, some of which regulate the movement of ions and charged molecules across the membrane, whilst others are concerned with maintaining the membrane electrical potential and with the passage of nutrients into the cell and unwanted metabolites out of the cell.