Question

The last electron acceptor in ETS (Electron Transport System) is:

• A. Oxygen (\( \mathrm{O_2} \))
• B. NADH
• C. FADH
• D. Carbon dioxide (\( \mathrm{CO_2} \))

Hint:

The equation for the final step in ETS is: \[ \mathrm{4H^+ + 4e^- + O_2 \to 2H_2O}. \] This process is vital for maintaining the proton gradient for ATP synthesis.

Answer 1

The Correct Option is A

In the Electron Transport System (ETS), oxygen (\( \mathrm{O_2} \)) serves as the final electron acceptor. The process is as follows: Electrons are transferred through a series of complexes in the inner mitochondrial membrane. At the end of the chain, electrons combine with \( \mathrm{O_2} \) and protons (\( \mathrm{H^+} \)) to form water (\( \mathrm{H_2O} \)). This reaction maintains the proton gradient essential for ATP synthesis. Thus, oxygen is crucial for the efficient production of ATP in aerobic respiration.