What molecules does the plasma membrane composed primarily of

The cell membrane is primarily composed of phospholipids and proteins and is referred to as a phospholipid bilayer.

Phospholipids make up the basic structure of a the cell membrane. A single phospholipid molecule has two different ends namely a head and a tail. The head contains a phosphate group and is hydrophilic which means it is attracted to water molecules.

The tail end is made of two strings of hydrogen and carbon atoms called fatty acid chains. These chains are hydrophobic or do not mingle with water molecules.