Question

Why do phospholipids form a bilayer in water?

Answer 1

Phospholipids are the molecule that makes up the membranes of cells. Cellular membranes are formed from a double layer of phospholipids, which is called the phospholipid bilayer. This layer helps the cell regulate what materials move in and out of the cell.

Phospholipids form a double layer because of their structure. They are made up of a hydrophilic head and a hydrophobic tail. The heads of the phospholipids are attracted to the fluid inside and outside of the cell, so the molecules orient themselves so that there is a layer of heads facing the inside of the cell and a layer of heads facing the outside of the cell. The tails form a double layer in the middle, away from the fluid.