Question

Explain ETS?

Answer 1

• ETS or electron transport system is located in the inner mitochondrial membrane. It helps in releasing and utilizing the energy stored in NADH${}_2$ and FADH${}_2$.
• NADH${}_2$ which is formed during glycolysis and the citric acid cycle gets oxidized by an NADH dehydrogenase (complex I). The electrons so generated get transferred to ubiquinone through FMN.
• In a similar manner, FADH${}_2$ (complex II) generated during the citric acid cycle gets transferred to ubiquinone. The electrons from ubiquinone are received by cytochrome bc1 (complex III) and further get transferred to cytochrome c.
• The cytochrome c acts as a mobile carrier between complex III and cytochrome c oxidase complex, containing cytochrome a and a${}_3$, along with copper centres (complex IV).
• During the transfer of electrons from each complex, the process is accompanied by the production of ATP from ADP and inorganic phosphate by the action ATP synthase (complex V).
• The amount of ATP produced depends on the molecule, which has been oxidized. 3 ATP molecules are produced by the oxidation of one molecule of NADH. One molecule of FADH${}_2$, on oxidation, gives 2 ATP molecules.