CoQ10 is a 1,4-benzoquinone where Q refers to the quinone chemical group and 10 refers to the number of isoprenyl chemical subunits. This oil-soluble substance is present in most eukaryotic cells, primarily in the mitochondria. It is a component of the electron transport chain and participates in aerobic cellular respiration, generating energy in the form of ATP. CoQ10 is used as a dietary supplement. Its supplementation is used in very rare cases of mithocondrial disorders where patients are not capable of producing enough coenzyme Q10. Ubiquinone supplementation is also found to be useful in teratment of cancer and migraine.