what functions do memebrane serve what does it mean to say t

what functions do memebrane serve? what does it mean to say that memebrane proteins are distributed asymmetrically?how do we know this?

Solution

Function of Membranes

Membranes serve several important functions: compartmentation oi enzyme systems, receptor recognition of hormone signals, generation of chemical and electrical signals, selective transport of molecules. and cell-to-cell recognition and adhesion.

Assymetrical distribution of Membrane proteins

Membrane proteins are distributed asymmetrically to provide localization of enzyme activity, energy transduction
through ion pumps, facilitated transport, and receptors for extracellular signals. Assymetrical distribution of protein membranes indicate that they can be associated with one side or the other side of the lipid bilayer.

The outer and inner regions of the plasma membrane do not contain either the same types or equal amounts of the various peripheral and integral proteins. For ex­ample, the outer half of the erythrocyte membrane contains far less protein than does the inner half. Various membrane proteins may be present in significantly different quantities; the membranes of some cells contain a hundred times as many molecules of one protein species as another. Moreover, regard­less of absolute quantity, all copies of a given mem­brane protein species have exactly the same orienta­tion in the membrane.There is differential distribution of proteins in the various regions of the plasma mem­brane within a single cell.This irregular distribution of membrane proteins is known as membrane asymmetry.