Lipid bilayer

Definition

A lipid bilayer is a thin polar membrane made of two layers of lipid molecules. These layers are composed primarily of phospholipids, which have hydrophilic (water-attracting) heads and hydrophobic (water-repelling) tails, forming a barrier that separates the cell from its external environment.

Related terms

Phospholipid: A type of lipid molecule that is a major component of all cell membranes as it can form lipid bilayers due to its amphiphilic characteristics.

Hydrophilic:

Refers to molecules or parts of molecules that are attracted to water and can dissolve in it easily, such as the "head" part of a phospholipid in a lipid bilayer.

Hydrophobic:

Describes molecules or portions of molecules that repel water and do not dissolve in it, like the "tail" part of a phospholipid in a lipid bilayer.