Glycerophospholipids

The glycerophospholipids are made up of three parts:  a three-carbon glycerol backbone, a phosphorylated headgroup and two hydrocarbon fatty acid chains. The phosphorylated headgroup is attached to carbon-3 of the glycerol backbone, although the two fatty acid chains are attached to the other two carbon atoms.  The easiest glycerophospholipid is phosphatidate (diacylglycerol 3-phosphate) that has only a phosphoric acid collection esterified to carbon- 3 of the glycerol.  While phosphatidate itself is present in small amounts in membranes, the main glycerophospholipids are derived from it. In these other lipids the phosphate is additional esterified to the hydroxyl group of one of various alcohols ethanolamine, choline, serine, inositol or glycerol. The main glycerophospholipids found in membranes involve phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylserine. Diphosphatidylglycerol or cardiolipin is found predominantly in the inner mitochondrial membrane.

           Figure: Structures of membrane glycerophospholipids. R1 and R2 represent hydrocarbon chains of fatty acids.