explanation
Mitochondria are cytoplasmic organelles that perform many important functions. The best known of these functions is the metabolism/oxidation of small substrates and fatty acids to ultimately produce the cell's major energy source, ATP. In addition, mitochondria participate in initiation of an important version of programmed cell death, and in some bio-synthetic steps resulting in steroid biosynthesis. Mitochondria participate indirectly in cell replication, and are capable of both fusion and fission, processes that are connected to their ability to generate ATP. In order to coordinate their capabilities with overall cellular needs, mitochondria interact with a number of cellular regulatory pathways, a very active area of current research.