Phospholipids Are Amphiphatic Molecules
- Phospholipids are amphipathic molecules, meaning they have both hydrophilic and hydrophobic regions:
- Hydrophilic Head: The phosphate group forms the head, which is polar and interacts readily with water.
- Hydrophobic Tails: Two hydrocarbon tails that are non-polar and repel water.
- This dual nature allows phospholipids to form a bilayer in aqueous environments, with hydrophilic heads facing outward toward water and hydrophobic tails clustered inward, away from water.
Definition
Amphiphatic
A molecule with both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions, such as a phospholipid.
The Hydrophobic Core and Permeability
- The hydrophobic core formed by the phospholipid tails limits the membrane’s permeability to certain substances:
- Hydrophilic Particles: Ions and polar molecules, such as glucose, cannot easily cross due to their affinity for water.
- Large Molecules: Substances like glycogen and proteins are too large to pass through without assistance.
