Among the following, the maximum redox
potential is for:
a) NADH/NAD
b) Succinate/Fumarate
c) Ubiquinone
d) Fe+3/ Fe+2
Correct Answer - D
Ans. D i.e. Fe+3/ Fe+2
Because electrons tend to flow spontaneously from carries of lower
redox potential (E°) to carries of higher redox potential. The order
(sequence) of electron carriers in ETC of mitochondria (and so the
increasing order of redox potential) is
Substrate → NADP+ /NADPH —> NADVNADH —› NADH
dehydrogenase (FMN) / NADH dehydrogenase (FMNH2) —>
FAD/FADH2 —> Ubiquinone or Coenzyme Q —> Fe3+ / Fee* in
cytochromes b —> C —> a -+ a3 —> 02