At which stage of the Krebs cycle does oxidative decarboxylation take place?
Correct answer: B. Isocitrate → α-Ketoglutarate
- A. Citrate → Isocitrate
- B. Isocitrate → α-Ketoglutarate
- C. Succinyl-CoA → Succinate
- D. Succinate → Fumarate
Explanation
The correct answer is option B, Step 3, where isocitrate is converted to α-ketoglutarate. This stage involves both oxidation and the release of carbon dioxide, fulfilling the definition of oxidative decarboxylation. The other options are incorrect because option A involves only isomerization, option C involves energy generation through substrate-level phosphorylation, and option D involves oxidation without carbon dioxide release.
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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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