During a single turn of the tricarboxylic acid (TCA) cycle, there are exactly three points where NAD ⁺ is reduced to NADH + H ⁺ . Which of the following represents the correct set of substrates that undergo oxidation at these three specific points?

Step-by-step solution

In the TCA cycle, there are three specific steps where NAD ⁺ acts as an electron acceptor and is reduced to NADH + H ⁺ . These steps involve the oxidation of the following substrates: 1. Isocitrate is oxidised to -ketoglutaric acid. 2. -ketoglutaric acid is oxidised to Succinyl-CoA. 3. Malic acid is oxidised to Oxaloacetic acid. Succinic acid oxidation reduces FAD to FADH ₂ , not NAD ⁺ . The conversion of Succinyl-CoA to Succinic acid involves substrate-level phosphorylation, and Fumaric acid undergoes hydration to