What is the lipid bilayer?

The lipid bilayer is a thin, flexible, semi-permeable, fluid-like membrane that encloses a cell, marking its boundaries and separating the interior of the cell from its extracellular environment.

It is called ‘lipid bilayer’ because it is made up of two layers of lipid molecules. Each lipid molecule consists of a hydrophilic head and a hydrophobic tail.

The lipid bilayer is embedded throughout with proteins such as receptor proteins, carrier proteins, and ion channels. It is a universal component of all cell membranes and performs several critical functions including:

• Providing cellular rigidity and support
• Maintaining ionic homeostasis
• Facilitating cell communication and signaling
• Regulating the transport of substances in and out of the cell
• Transporting nutrients into the cell and expelling toxic substances out of the cell