[Mitochondria in cell life, death and disease].

In animal cell, mitochondria are the main sites of the synthesis of ATP required for cell functioning and survival. On the other hand, mitochondria play a key role in initiating cell programmed death (apoptosis). In addition, defects in the mitochondrial genome and in the nuclear genome encoding mitochondrial proteins may result in malfunctioning of these organelles and, as result, in diseases of the whole organism. This article contains basic information on the functioning of oxidative phosphorylation and on mitochondrial production of reactive oxygen species. It also describes initiation of apoptosis at the mitochondrial level. Finally, it briefly presents some most common genetic defects responsible for "mitochondrial diseases".