Here's why:
* Phospholipid bilayer: The cell membrane is primarily composed of a phospholipid bilayer. These phospholipids have a distinct structure:
* Head: The head of a phospholipid is hydrophilic (water-loving). It contains a phosphate group, which is polar and interacts readily with water molecules.
* Tail: The tail of a phospholipid is hydrophobic (water-fearing). It consists of fatty acid chains, which are nonpolar and repel water.
* Attraction: The hydrophilic heads of the phospholipids face the watery environment inside and outside the cell. They form hydrogen bonds with water molecules, attracting them to the cell membrane.
* Barrier: The hydrophobic tails of the phospholipids face each other in the middle of the membrane, forming a barrier that prevents water-soluble substances from passing through easily. This selective permeability is crucial for maintaining the cell's internal environment.
In summary, the hydrophilic head of the phospholipid in the cell membrane attracts water molecules, contributing to the cell's ability to maintain its internal environment and interact with its surroundings.
