What Is an Amphipathic Molecule?

Amphipathic molecules are molecules having both polar and non-polar portions in their structure. The chemical compounds that feature these molecules are essential to a host of biological and industrial processes.

Soaps, detergents and lipoproteins are examples of amphipathic molecules. The non-polar portion of an amphipathic molecule is hydrophobic, meaning that it is repelled from water molecules. This non-polar portion is also lipophilic, meaning that it is attracted to other organic molecules. The non-polar part is usually a long-chain hydrocarbon.

The polar portion of the molecule may be composed of different radical groups including carboxylates, sulfates, phosphates and sulfonates. This polar portion behaves in a way that is almost opposite to the non-polar part, as it is attracted to water and repelled by polar molecules.

Amphipathic compounds often have several lipophilic and several hydrophilic parts attached to a central carbon backbone. Phospholipids are a class of amphipathic molecule that is essential to life. These molecules are the main component of biological membranes. The specific amphipathic behavior of phospholipid molecules is determined by how they combine. Other important biosynthesized amphipathic molecules are cholesterol and glycolipids.

Artificial amphipathic molecules can be tailored to attract and exfoliate unwanted organic species, enabling them to function as surfactants.