Question

How does the formation of NAD+ differ between aerobic and anaerobic respiration?

A. NAD+ is formed in aerobic respiration by a fermentation process and formed in anaerobic respiration by oxidation of NADH.

B. NAD+ is formed by a fermentation process in anaerobic respiration by the conversion of pyruvate into lactate and by simple oxidation of NADH in aerobic respiration.

C. Under aerobic conditions, the electron acceptor is a molecule other than oxygen for NAD+ production, whereas under anaerobic conditions the electron acceptor is oxygen.

D. NAD+ is formed by the breakdown of pyruvate to form oxaloacetate in anaerobic respiration whereas in aerobic respiration it is formed by the breakdown of pyruvate into lactic acid or alcohol.

Answer 1

B. NAD+ is formed by a fermentation process in anaerobic respiration by the conversion of pyruvate into lactate and by simple oxidation of NADH in aerobic respiration.

Step-by-step explanation:

Nicotinamide adenine dinucleotide (NAD) is an important coenzyme that may exist in two different forms: oxidized (NAD+) and reduced (NADH). The fermentation is an anaerobic oxidation-reduction reaction where pyruvate and NADH are reactants, while lactate and NAD+ are products generated by the oxidation of NADH to NAD+ and pyruvate to lactate, respectively. On the other hand, during aerobic respiration, NADH generated by glycolysis is oxidized to form NAD+ by the donation of its electrons to reduce pyruvate to lactate. Subsequently, NAD+ is reused in glycolysis (again) in order to generate more molecules of ATP.