A membrane lipid is a compound which belongs to a group of (structurally similar to fats and oils) which form the double-layered surface of all cells (lipid bilayer). The three major classes of membrane lipids are phospholipids, glycolipids, and cholesterol.
Membrane lipids are amphipathic molecules that spontaneously form bilayers. Lipids are insoluble in water, but easily dissolve in organic solvents. In most animal cells, they make up about 50% of the mass of the plasma membrane.
