Why Do Cell Membranes Have a Double Layer?

💡 The Answer

• The double layer, or bilayer, is composed of phospholipids with hydrophilic heads and hydrophobic tails.
• This structure spontaneously forms in water to create a stable barrier that separates the cell interior from the outside.
• The bilayer's fluid nature allows for the insertion and movement of proteins that perform critical functions.
• Selective permeability of the bilayer controls the passage of ions and molecules essential for cell survival.