Question

The numbers of ATP molecules generated by one $NADH$ and one $FAD{H}_2$ are respectively

• A. 3, 2
• B. 2, 3
• C. 3, 5
• D. 5, 3

Answer 1

The correct option is A 3, 2

NADH donates its electrons to complex I. When electrons move from complex I through the ETS, protons are pumped across the membrane, which powers the ATP synthase and give 3 ATPs per molecule of NADH. $FAD{H}_2$ gives its electrons to complex II, bypassing complex I. So, in this case, only 2 ATP molecules are formed.