What reaction type occurs when isocitrate is converted to alpha-ketoglutarate?

The correct reaction type when isocitrate is converted to alpha-ketoglutarate is decarboxylation. This step in the citric acid cycle involves the removal of a carbon dioxide molecule from isocitrate, which results in the formation of alpha-ketoglutarate.

During this process, isocitrate undergoes an oxidation reaction where it is oxidized to form a transient intermediate, which then loses a carbon in the form of CO2. This decarboxylation not only reduces the carbon skeleton of the molecule but also facilitates the progression of the cycle by ensuring that the carbon atoms from the original substrate are gradually used in the formation of energy-carrying molecules.

Understanding this specific reaction is crucial, as it highlights how carbon atoms are efficiently removed in the cycle and how this contributes to the overall metabolic pathways that produce energy in aerobic respiration.