Natural uncoupler is-

Ans. is 'a' i.e., Thermogenin o Amongst the given options, a, b and c are uncouplers. o However, only thermogenin, among these three is a natural (physiological) uncoupler. Uncouples o As the name suggests, these compounds block the coupling of oxidation with phosphorylation. These compounds allow the transfer or reducing equivalents in respirators chain but prevent the phosphorylation of ADP to ATPy by uncoupling the linkage between ETC and phosphorylation. Thus the energy instead of being trapped by phosphorylation is dissipated as heat. Uncouplers may be NaturalThermogenin, thyroxine Synthetic 2, 4-dinitrophenol (2, 4-DNP), 2, 4-dinitrocresol (2, 4-DNC), and CCCP (chlorocarbonylcyanidephenyl hydrazone).