The plasma membrane or the cell
membrane is the one that protects the cytoplasm of a cell. It is mostly
composed of lipids and proteins. It has a phospholipid bilayer that controls
the entering and exiting of molecules in the cell and at the same time,
provides protection for the cell or plasma membrane. It has polar head and a
nonpolar tail. Proteins embedded within the phospholipid bilayer have the same
function of the plasma membrane that includes selective transport. The
phospholipid bilayer consists mainly of the lipid molecules.
