Question

In the cell membrane/plasma membrane/phospholipid bilayer, what do the peripheral and integral protein do?

Answer 1

Integral proteins act as ion channels, ion pumps and structural support; the peripheral proteins act as cell identity markers.

Explanation:

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 :

1. making transport channels for small dissolved ions;
2. acting as enzymes for the active transport of materials into the cell against a concentration gradient;
3. acting as receptor sites for hormones to gain entrance into the cell;
4. acting as structural supports inside the cell attaching to cytoskeleton structures, which hold organelles in place in the cytoplasm;
5. makeing up the structure of the sodium-potassium pump;

Function of peripheral proteins :

1. acting as cell identity markers;

Some facts about cell membrane proteins :