In the conversion of pyruvic acid to acetyl coenzyme-A, pyruvic acid gets:
Correct answer: C. Oxidized
- A. Reduced
- B. Broken into carbon fragments
- C. Oxidized
- D. Isomerized
Explanation
The conversion of pyruvic acid to acetyl-CoA is a critical step in cellular respiration. In this process, pyruvic acid is oxidised: it loses a carbon dioxide molecule and transfers electrons to NAD+, forming NADH. This results in the formation of acetyl-CoA, a key molecule for the Krebs cycle. The option 'Reduced' is incorrect because reduction involves electron gain, not loss. 'Broken into carbon fragments' is misleading because, although decarboxylation occurs, the molecule is not fragmented. 'Isomerised' is incorrect, as no rearrangement of atoms into different isomers takes place.
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About Bioenergetics
Cellular respiration explains how cells release energy from glucose through glycolysis, the link reaction, Krebs cycle and electron transport chain. It includes ATP production, substrate-level and oxidative phosphorylation, aerobic versus anaerobic respiration, and the roles of mitochondria, oxygen and fermentation in energy transfer.
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