Cross references:  Succinate dehydrogenase       

Mitochondrion (Wiki) 
    "In cell biology, a mitochondrion  (plural mitochondria) is a membrane-enclosed organelle found in most eukaryotic cells.[1] These organelles range from 0.5 to 1.0 micrometer (μm) in diameter. Mitochondria are sometimes described as "cellular power plants" because they generate most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy.[2] In addition to supplying cellular energy, mitochondria are involved in other tasks such as signaling, cellular differentiation, cell death, as well as the control of the cell cycle and cell growth.[3]
Although most of a cell's DNA is contained in the cell nucleus, the mitochondrion has its own independent genome. Further, its DNA shows substantial similarity to bacterial genomes.[12]"