The biomolecules that are made up of fatty acids are called lipids. Lipids are a diverse group of molecules that include fats, oils, phospholipids, and steroids. Fatty acids are the building blocks of lipids and consist of a long hydrocarbon chain with a carboxyl group (-COOH) at one end. When fatty acids combine with other molecules, such as glycerol or an alcohol, they form different types of lipids.
