Phospholipids are esters of glycerol with two carboxylic acid residue and one phosphate group. Hence, phospholipids may be regarded as derivative of glycerol in which two hydroxyl groups are esterified with fatty acid, while third is esterified with phosphoric acid. Related Theory The platform on which phospholipids are built may be glycerol, a 3- carbon alcohol, or sphingosine, a more complex alcohol. Phospholipids derived from glycerol are called phosphoglycerides.