Fatty acids

Fatty acids are an important source of energy for many organisms and excess glucose can be stored efficiently as fat. Triglycerides yield more than twice as much energy, for the same mass, as carbohydrates or proteins. All cell membranes are built up of phospholipids, each of which contains two fatty acids. The metabolism of fatty acids consists of catabolic processes which generate energy from fatty acids, and anabolic processes which create biologically important molecules from fatty acids.