What is the role of NAD+/NADH and FAD/FADH2 in cellular respiration?

• A. They are electron carriers that cycle between oxidized and reduced forms to transfer electrons to the ETC, enabling proton pumping and ATP production.
• B. They are enzymes that catalyze glycolysis steps.
• C. They are membrane lipids that form the bilayer.
• D. They are structural proteins in mitochondria.

Answer: (A)