Question

Which one of the following is an incorrect statement about mitochondrial ETC and oxidative phosphorylation?

• A. Enzyme complex I accepts electrons and $H^{+}$ from NADH and $FAD{H}_2$
• B. Passage of protons through the channel is coupled to the catalytic site of the $F_0-F_1$ particle for ATP production
• C. Cytochrome-c is a mobile protein attached on the outer surface of the inner membrane
• D. $6H^{+}$ ions pass through $F_0$ from intermembrane space to the matrix down the electrochemical proton gradient to produce 3 ATP molecules

Answer 1

The correct option is A Enzyme complex I accepts electrons and $H^{+}$ from NADH and $FAD{H}_2$

Electron transport chain is responsible for oxidative phosphorylation in which $e^{–}$ and $H^{+}$ of NADH are accepted by complex I and then the electrons move through different carriers. 6 protons are pumped in intermembranous space which later diffuse to the matrix through $F_0-F_1$ (ATP synthase) to form 3 ATP. $FAD{H}_2$ always enters in ETS through complex II. Cytochromes $b–c_1,c,anda–a_3$ are arranged in ETS according to the order of redox potential. Cytochrome c is a mobile electron carrier.