In: Biology
How does the electron transport chain and ATP synthase generate ATP? Where does this occur in a eukaryotic cell?
Mitochondria is known as power house of cell. Electron transport chain is located in the inner mitochondrial membrane. ETC contain 5 complex, arranged from more negative to more positive redox potential.
Complex I , NADH coQ reductase
Complex II succinate CO Q reductase
Complex III cytochrome reductase
Complex IV cytochrome oxidase
Complex V ATP synthase.
During catabolism of molecules in various metabolic pathways ( glycolysis, TCA etc.) Energy is released in form of reducing equivalents ( NADH and FADH2). These reducing equivalents enter in to ETC at either complex I or complex II level. ATP is produced by oxidative phosphorylation means oxidation ( oxidation of MADH and FADH2) followed by phosphorylation. These NADH and FADH2 transfer their electron to complex I and complex II respectively. As these electron transfer through the chain energy is released and this released energy is used to transport protons in to inter membrane space. So she to accumulation of H + in to enter membrane space , there is generation of PMF ( proton motive force). These H + re enter in to mitochondria matrix by ATP synthase complex. As protons enter through ATP synthase complex. There is rotation in F1 subunit of this complex, which catalyze the synthesis of ATP.
So ATP synthase is the main enzyme which is involved in synthesis of ATP. While protons accumulated in inter membrane space will provide or act as immediate energy source for synthesis of ATP.