<prompt> Which complex of ETC is not associated with liberation of energyComplex IComplex IIComplex IIIComplex IV  <response>: Components of ETCProsthetic group Features Complex I NADH dehydrogenase NADH Co-Q reductase NADH Ubiquinone FMN , FeSEnergy - 12 KcalmolTo pump 4 protons out of mitochondria into inter membranous spaceComplex IISuccinate dehydrogenase Succinate Q reductaseFAD , FeSNot a proton pump as energy is liberated Coenzyme Q Ubiquinone Q Non protein member of ETC For transferring to complex III it accepts hydrogen atoms from 1.FMNH2 produced in complex I2.FADH2 produced in complex II3.FADH2 produced in beta oxidation by acyl CoA dehydrogenase glycerol 3 phosphate dehydrogenase Complex IIICytochrome bC1 complex Ubiquinone cytochrome C oxidoreductase Cytochrome reductase FeS , Heme Energy - 10 KcalmolTo pump 4 protons out of mitochondria into inter membranous spaceCytochrome C Soluble carrier protein of intermembranous space Complex IV Cytochrome C oxidase Cytochrome oxidase 2 Heme , 2 Copper ions of CuA , CuBTo pump 2 protons out of mitochondria into inter membranous spaceHarpers illustrated Biochemistry , 30th ed , page 131 