phospholipids
The plasma membrane is composed mainly of phospholipids, which consist of fatty acids and alcohol. The phospholipids in the plasma membrane are arranged in two layers, called a phospholipid bilayer . As shown in Figure below , each phospholipid molecule has a head and two tails. The head loves water hydrophilic and the tails hate water hydrophobic . The water-hating tails are on the interior of the membrane, whereas the water-loving heads point outwards, toward either the cytoplasm or the fluid that surrounds the cell.