Phospholipid Bilayer

The Cell Membrane a phospholipid bilayer

A Selectively Permeable Barrier

Cell Membrane The cell membrane protects the cell by controlling what can enter and exit the cell. (keeps the insides in and the outside out) It is also called the plasma membrane.

Phospholipids Cell membranes are made of a special type of lipid molecule called a phospholipid. The most important quality of phospholipids is that they have a hydrophilic head and hydrophobic tails.

Fig (b) Space-filling model (a)(c) Structural formula Phospholipid symbol Fatty acids Hydrophilic head Hydrophobic tails Choline Phosphate Glycerol Hydrophobic tails Hydrophilic head

Fig. 7-2 Hydrophilic head WATER Hydrophobic tail WATER

Fluid mosaic Bc Bc