Question

Fate of pyruvic acid during aerobic respiration is

• A. lactic acid fermentation
• B. alcoholic fermentation
• C. oxidative decarboxylation
• D. oxidative phosphorylation

Answer 1

Answer: (C)

oxidative decarboxylation

Answer 2

During aerobic respiration, pyruvic acid which is formed during glycolysis enters mitochondrial matrix. It undergoes oxidative decarboxylation to produce $CO_2$ and $NADH$. The product combines with sulphur containing coenzyme $A$ to form acetyl $CoA$. This reaction is catalysed by an enzyme complex pyruvate dehydrogenase. This step is called link reaction or gateway step as it links glycolysis with Krebs' cycle. Pyruvic acid $+ CoA + NAD^+$ ${->[Mg^{2+}][\text{Pyruvate dehyrogenase}] }$ Acetyl $CoA + CO_2 + NADH + H^+$