Amphipathic

Definition

Amphipathic molecules have both hydrophilic (water-loving) and hydrophobic (water-fearing) regions. This unique characteristic allows them to interact with both water and lipid environments.

5 Must Know Facts For Your Next Test

1. Amphipathic molecules are crucial components of cell membranes, forming the lipid bilayer.
2. The hydrophilic head typically faces outward towards water, while the hydrophobic tail faces inward away from water.
3. Common examples include phospholipids, detergents, and certain proteins.
4. The amphipathic nature is essential for the formation of micelles and liposomes in aqueous solutions.
5. The arrangement of amphipathic molecules in a bilayer creates a semi-permeable membrane that regulates the passage of substances.

Review Questions

• What structural feature makes a molecule amphipathic?
• How do amphipathic molecules contribute to the formation of cell membranes?
• Name two examples of amphipathic molecules commonly found in biological systems.

Related terms

Phospholipid: A type of lipid molecule that is a major component of cell membranes, consisting of two fatty acids and a phosphate group attached to glycerol.

Micelle: An aggregate of surfactant molecules dispersed in a liquid colloid, where the hydrophobic tails are oriented inward and the hydrophilic heads face outward.

Lipid Bilayer:

A thin polar membrane made of two layers of lipid molecules; these layers form a continuous barrier around cells.