Bilayers

Bilayers are structures made up of two layers of molecules, primarily phospholipids, that form the fundamental framework of cell membranes. Each phospholipid has a hydrophilic (water-loving) head and hydrophobic (water-fearing) tails. In a bilayer, these molecules arrange themselves so that the heads face outward toward water and the tails face inward, creating a flexible, semi-permeable barrier. This setup allows cells to protect their internal environment, regulate substances entering and leaving, and communicate with their surroundings. The bilayer's structure is essential for maintaining life by providing both protection and controlled exchange with the environment.