During the continuous operation of the Krebs cycle, carbon is lost in the form of CO₂ . Which of the following intermediate conversions represents one of these decarboxylation events?

Step-by-step solution

In the Krebs cycle, decarboxylation (loss of CO₂ ) occurs at two specific steps: 1. Conversion of isocitric acid (a 6-carbon compound) to -ketoglutaric acid (a 5-carbon compound). 2. Conversion of -ketoglutaric acid (a 5-carbon compound) to succinyl-CoA (a 4-carbon compound). Among the given options, the conversion of -ketoglutaric acid to succinyl-CoA involves the release of CO₂ . The other conversions do not involve any change in the number of carbon atoms and thus do not represent decarboxylation events. Answer: