Question

8. The citric acid cycle requires acetyl-CoA to begin. Describe how acetyl-CoA is produced for the citric acid cycle.

Answer 1

The production of Acetyl-CoA depends upon the Glycolysis.

When Glycolysis occurs, it converts Glucose into Pyruvate via a metabolic pathway which consists of Ten enzyme catalyzed reactions.

The final product of Glycolysis cycle is Pyruvate which is then converted into Acetyl-CoA with CO₂ and NADH+H⁺ in the mitochondria with the help of enzyme complex Pyruvate Dehydrogenase Complex and the process is called Pyruvate Decarboxylation. That's how this resulting Acetyl-CoA enters the Citric Acid Cycle and then utilized in the cycle.

The reaction for the conversion of Pyruvate into Acetyl-CoA is - 1 Pyruvate + 1 NAD⁺ + CoA → 1 Acetyl-CoA + NADH + CO₂ + ​H⁺

^{For a Glycolysis cycle, single molecule of Glucose converts into 2 molecules of Pyruvate. Each single Pyruvate converts into only one Acetyl-CoA. So, from a 1 Glucose molecule or a single Glycolysis will results in 2 molecules of Acetyl-CoA.}