Answer
A small part of the cell membrane is made up of two types of proteins: integral and peripheral. Integral proteins, are those that go through the membrane completely or penetrate the lipid bilayer. Peripheral proteins, unlike integral proteins, simply stick to one side of the membrane, often being attached to other regions of the cell.
Work Step by Step
Because of the amphiphilic structure of the phospholipid bilayer, integral proteins have hydrophilic areas in contact with the extracellular and intracellular parts of the cell, and hydrophobic areas in contact with the tails of the phospholipids. These proteins usually float around freely in the membrane, but some are attached to the cell's cytoskeleton. Peripheral proteins are usually attached to transmembrane proteins, which are proteins that completely go through the membrane. Peripheral proteins, like integral proteins, can also be attached to the cytoskeleton.
