In the Krebs cycle, for the formation of α-ketoglutarate, the following changes occur, EXCEPT:

Explanation

In the formation of α-ketoglutarate during the Krebs cycle, several key changes occur that contribute to the cycle's energy yield. Isocitrate undergoes NAD-mediated oxidation, where electrons are transferred to NAD⁺, forming NADH. This step is crucial because it captures high-energy electrons that will later be used in ATP production. Simultaneously, the reaction involves decarboxylation, releasing a molecule of carbon dioxide and reducing the carbon count from six in isocitrate to five in α-ketoglutarate. Both the NAD-mediated oxidation and decarboxylation are essential for the proper transformation of isocitrate into α-ketoglutarate. The formation of NADH also occurs as a direct result of this oxidation, providing the reducing power necessary for the electron transport chain. Hydration, however, does not take place in this step. Hydration reactions occur in other parts of the Krebs cycle, such as the conversion of fumarate to malate, but the formation of α-ketoglutarate specifically involves only oxidation and decarboxylation, making hydration incorrect in this context.