What type of reaction occurs when succinate is converted to fumarate in the Citric Acid Cycle?

The conversion of succinate to fumarate in the Citric Acid Cycle is classified as a dehydrogenation reaction. This type of reaction involves the removal of hydrogen atoms from a molecule, which in this context results in the conversion of the saturated four-carbon compound succinate into the unsaturated four-carbon compound fumarate.

During this transformation, succinate loses two hydrogen atoms, which are transferred to a molecule of FAD (flavin adenine dinucleotide), reducing it to FADH2. This step is crucial because the electron carriers are integral to the pathway, facilitating the subsequent steps in the Citric Acid Cycle by contributing to the electron transport chain where ATP is ultimately produced. Thus, identifying this reaction as a dehydrogenation emphasizes the role of electron transfer and oxidation-reduction processes in the cycle.