Lipid Bilayers Are The Basis of Cell Membranes
- The lipid bilayer forms the foundation of all cell membranes, defining the boundary between a cell and its environment.
- This versatile structure controls the passage of substances into and out of the cell while maintaining compartmentalization within eukaryotic cells.
The Essential Structure of the Lipid Bilayer
- The lipid bilayer consists of two layers of phospholipids and other amphipathic molecules.
- These specialized molecules self-assemble into a bilayer due to their unique chemical properties:
- Hydrophilic heads (polar regions) face outward toward water.
- Hydrophobic tails (non-polar regions) cluster inward, away from water.
Structure of a Phospholipid
- Hydrophilic Head: The polar phosphate group forms the head, which readily interacts with water.
- Hydrophobic Tails: The nonpolar hydrocarbon chains make up the tails which avoid water.
- This amphipathic nature is key to the behavior of phospholipids in water.
- When introduced into an aqueous environment, they spontaneously arrange themselves to shield their hydrophobic tails while exposing their hydrophilic heads to water.
Definition
Amphipathic
Amphipathic: A molecule that has both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions.
