Cell membrane

The cell membrane (also called the plasma membrane, plasmalemma, or phospholipid bilayer) is the interface between the cellular machinery inside the cell and the fluid outside.

It is a semipermeable lipid bilayer found in all cells. It contains a wide variety of biological molecules, primarily proteins and lipids, which are involved in a vast array of cellular processes such as cell adhesion, ion channel conductance and cell signaling. The plasma membrane also serves as the attachment point for both the intracellular cytoskeleton and, if present, the extracellular cell wall.