Fig. 3.

Mitochondria as a source of ATP production and reactive oxygen species (ROS). The figure shows the electron transport chain present in the inner mitochondrial membrane and the process of ATP synthesis and production of ROS as a byproduct. The complexes (I-IV) transfer electrons and reach oxygen, the final electron acceptor. This flow of electrons also pumps protons out of the matrix concomitantly, creating an electrochemical gradient that helps synthesise ATP from ADP and inorganic phosphate (Pi). The ROS such as ONOO- and ^•OH generated due to leak of electrons can lead to oxidative damage and mitochondrial dysfunction, which play a central role in the pathogenesis of many diseases.