Question

The ultimate electron acceptor of respiration in an aerobic organism is

• A. cytochrome
• B. oxygen
• C. hydrogen
• D. glucose

Answer 1

Answer: (B)

oxygen

Answer 2

The electron transport chain catalyses an electron flow from $NADH\, (FADH_2)$ to oxygen, which is the final electron acceptor of the respiratory process. It produces water in the mitochondrial matrix. $NADH + H^{+} \rightleftharpoons NAD^{+} + 2H^{+}+2e^{-}$ $FADH_{2} \rightleftharpoons FAD + 2H^{+} + 2e^{-}$ $\frac{1}{2}O_{2} + 2H^{+} + 2e^{-} \to H_{2}O$