Fatty acids have four main biological roles:
1. They are used to create sphingolipids and glycerophospholipids which are necessary elements of biological membranes;
2. Numerous proteins are covalently modified by fatty acids. palmitate (C16:0) and Myristate (C14:0) are straightly attached to some proteins, thus phosphatidylinositol is covalently connected to the C terminus of other proteins by a complex glycosylated structure;
3. Fatty acids act as fuel molecules, being collected as triacylglycerols and broken down to make energy;
4. Derivatives of fatty acids serve as hormones (like as the prostaglandins) and intracellular second messengers (like as DAG and IP3).