Electron transport chain is a vital process that occurs within the inner mitochondrial membrane (also found in the plasma membrane of prokaryotes) during cellular respiration. It is a series of protein complexes and coenzymes involved in the transfer of electrons from energy-rich molecules, such as NADH and FADH2, to molecular oxygen (O2), thereby generating ATP (adenosine triphosphate), which is the main energy currency of the cell.
During the electron transport chain, electrons are passed sequentially through a series of protein complexes, including NADH dehydrogenase (Complex I), succinate dehydrogenase (Complex II), cytochrome bc1 complex (Complex III), and cytochrome c oxidase (Complex IV). These complexes are embedded in the mitochondrial membrane and play a crucial role in receiving, donating, and transferring electrons through redox reactions.
Each complex in the electron transport chain actively pumps protons (H+) across the membrane, establishing an electrochemical potential gradient. This gradient drives the synthesis of ATP through oxidative phosphorylation. Finally, the terminal electron acceptor, molecular oxygen, combines with the electrons and protons to form water (H2O) in Complex IV.
Overall, the electron transport chain is a highly efficient process that enables the generation of large amounts of ATP by utilizing the energy released from the transfer and flow of electrons. It is an essential component of aerobic metabolism and plays a pivotal role in sustaining energy production in all living organisms.
