Question

The ultimate electron acceptor of respiration in an aerobic organism is

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

Answer 1

Answer: (B)

The electron transport chain catalyses an electron flow from $NADH(FAD{H}_2)$ to oxygen, which is the final electron acceptor of the respiratory process. It produces water in the mitochondrial matrix.
$NADH+H^{+}\rightleftharpoons NA{D}^{+}+2H^{+}+2e^{-}$
$FAD{H}_2\rightleftharpoons FAD+2H^{+}+2e^{-}$
$\frac{1}{2}{O}_2+2H^{+}+2e^{-}\to H_{2}O$