Integral proteins act as ion channels, ion pumps and structural support; the peripheral proteins act as cell identity markers.
Structure of a cell membrane :
Proteins of the cell membrane is divided into two groups : Integral proteins (directly incorporated within the lipid bi-layer) and Peripheral proteins (loosely associated with membrane surface).
Functions of the integral proteins :
- making transport channels for small dissolved ions;
- acting as enzymes for the active transport of materials into the cell against a concentration gradient;
- acting as receptor sites for hormones to gain entrance into the cell;
- acting as structural supports inside the cell attaching to cytoskeleton structures, which hold organelles in place in the cytoplasm;
- makeing up the structure of the sodium-potassium pump;
Function of peripheral proteins :
- acting as cell identity markers;
Some facts about cell membrane proteins :