Question

Terminal electron acceptors in lactic acid fermentation and ethanol fermentation, respectively are

• A. pyruvate and acetaldehyde
• B. acetaldehyde and pyruvate
• C. oxygen and pyruvate
• D. oxygen and acetaldehyde

Answer 1

The correct option is A pyruvate and acetaldehyde

In fermentation, the incomplete oxidation of glucose is achieved under anaerobic conditions. This can occur in two ways - lactic acid fermentation and ethanol fermentation.

In lactic acid fermentation, pyruvate from glucose after glycolysis is converted to lactic acid. Pyruvate is the terminal electron acceptor. Pyruvate receives electrons from NADH and gets itself reduced to lactic acid (lactate).

In ethanol fermentation, pyruvate from glucose after glycolysis is converted to carbon dioxide and ethanol. The terminal electron acceptor is acetaldehyde which receives electrons from NADH and gets itself reduced to ethanol.