Every living organism on Earth uses coenzymes in various important enzyme-catalyzed reactions, for example, ones that are involved in the central metabolic pathways such as glycolysis and the Krebs cycle. Many species can synthesize their own coenzymes from simple precursors, which is very important in four out of five kingdoms: prokaryotes, protozoa, fungi, and plants. On the other hand, animals don't have the ability to produce some of the coenzymes, hence they have to consume it through their diet.