Question

The NADH formed in glycolysis must be recycled to regenerate NAD⁺, under anaerobic conditions. Yeast regenerates NAD⁺ by 

(a) transferring electrons from NADH to pyruvate 

(d) transferring electrons from NADH to O₂ in mitochondrial respiration 

(c) reducing pyruvate to ethanol and CO₂ 

(d) None of the above

Answer 1

Correct option: (c) reducing pyruvate to ethanol and CO₂ 

In anaerobic respiration (fermentation), there is no net oxidation or reduction of the carbons of glucose.

The anaerobic regeneration of NAD is called fermentation. In yeast, the regeneration of NAD from NADH takes place under anaerobic conditions. Here pyruvate is converted into ethanol and CO₂ in a two steps reaction.