(b) : Chemically a biomembrane consists of lipids (20−70%), proteins (20−70%), carbohydrates (1−5%) and water (20%). The important lipids of the membrane are phospholipids (some hundred types), sterols, (e,g. cholesterol), glycolipids, sphingolipid (e,g⋅) sphingomyelin, cerebrosides). Protein can be fibrous or globular structural carrier, receptor or enzymatic.