What is the composition of the plasma membrane?

The plasma membrane, also known as the cell membrane, is composed of a phospholipid bilayer, which consists of two layers of phospholipid molecules. The phospholipid bilayer is embedded with proteins, which have various functions such as transporting molecules in and out of the cell, cell signalling, and structural support. Therefore, the plasma membrane is composed of both proteins and lipids. Carbohydrates are also present on the outer surface of the plasma membrane, but they are not a major component of its structure.