What is the basic reaction for anaerobic respiration/fermentation described?

What is the basic reaction for anaerobic respiration/fermentation described?

• A. Glucose => acetyl-CoA + NADH
• B. Glucose => CO2 + H2O + 36 ATP
• C. Glucose => ethanol + CO2 + 2 ATP
• D. Glucose => pyruvic acid + 2 ATP => Lactic Acid

Answer: (D)

Under anaerobic conditions, cells make a small amount of ATP by glycolysis and must regenerate NAD+ so glycolysis can continue. This happens when pyruvate, the end product of glycolysis, is reduced to lactate, using electrons from NADH. That way, NAD+ is replenished and glycolysis can keep producing ATP without oxygen. So glucose is first converted to pyruvate (via glycolysis), yielding 2 ATP, and then pyruvate is converted to lactic acid. This sequence—glucose to pyruvic acid with 2 ATP, followed by conversion to lactic acid—captures how fermentation sustains ATP production in the absence of oxygen. Options that describe full oxidation to CO2 and H2O or production of ethanol point to other metabolic routes (aerobic respiration or alcoholic fermentation) that aren’t the described lactate-forming anaerobic pathway.

Under anaerobic conditions, cells make a small amount of ATP by glycolysis and must regenerate NAD+ so glycolysis can continue. This happens when pyruvate, the end product of glycolysis, is reduced to lactate, using electrons from NADH. That way, NAD+ is replenished and glycolysis can keep producing ATP without oxygen. So glucose is first converted to pyruvate (via glycolysis), yielding 2 ATP, and then pyruvate is converted to lactic acid. This sequence—glucose to pyruvic acid with 2 ATP, followed by conversion to lactic acid—captures how fermentation sustains ATP production in the absence of oxygen.

Options that describe full oxidation to CO2 and H2O or production of ethanol point to other metabolic routes (aerobic respiration or alcoholic fermentation) that aren’t the described lactate-forming anaerobic pathway.