<unk>  consists of various metabolic processes involving or closely related to<unk> <unk> s, a family of molecules classified within the lipid macronutrient category. These processes can mainly be divided into (1) catabolic processes that generate energy and (2) anabolic processes where they serve as building blocks for other compounds. In catabolism,<unk> <unk> s are oxidized via beta oxidation and the citric<unk>  cycle to produce energy, mainly in the form of adenosine triphosphate (ATP). Compared to other macronutrients (carbohydrates and proteins) on a per gram basis, oxidation of<unk> <unk> s to CO and water yields the most ATP because they contain fewer oxygen atoms and unlock the energy of more O.<unk> <unk> s (mainly in the form of triglycerides) are therefore the foremost storage form of fuel in most animals, and to a lesser extent in plants. In anabolism, intact<unk> <unk> s are important precursors to triglycerides, phospholipids, second messengers, hormones and ketone bodies. For example, phospholipids form the phospholipid bilayers out of which all the membranes of the cell are constructed from<unk> <unk> s. Phospholipids comprise the plasma membrane and other membranes that enclose all the organelles within the cells, such as the nucleus, the mitochondria, endoplasmic reticulum, and the Golgi apparatus. In another type of anabolism,<unk> <unk> s are modified to form other compounds such as second messengers and local hormones. The prostaglandins made from arachidonic<unk>  stored in the cell membrane are probably the best-known of these local hormones.
Fatty acid metabolism
Lipid metabolism
Ethanol metabolism
Purine metabolism
Mitochondrial biogenesis
Glucose uptake
Pyrimidine metabolism
Drug metabolism