Which step of the Citric Acid Cycle is associated with the production of FADH2?

In the Citric Acid Cycle, Step 6 is where FAD (flavin adenine dinucleotide) is reduced to FADH2. This step involves the enzyme succinate dehydrogenase, which catalyzes the oxidation of succinate to fumarate. During this reaction, two hydrogen atoms are removed from succinate, leading to the formation of FADH2. This production of FADH2 is significant because it plays a crucial role in the electron transport chain, where it helps to generate ATP through oxidative phosphorylation.

FADH2 acts as an electron carrier, donating electrons to the electron transport chain, ultimately contributing to the synthesis of ATP. The efficiency and energy yield of the cycle enhance significantly due to the involvement of FADH2.

In contrast, the other steps do not involve the production of FADH2. Step 5 involves the conversion of succinyl-CoA to succinate and production of GTP or ATP. Step 7 involves the hydration of fumarate to malate, and Step 8 involves the oxidation of malate to oxaloacetate, which produces NADH. Thus, Step 6 is specifically recognized as the step that produces FADH2, highlighting its role