Citric Acid Cycle Practice Exam 2026 – Comprehensive Test Prep

The connection between glycolysis and the Citric Acid Cycle (CAC) is established through the conversion of pyruvate to acetyl-CoA. During glycolysis, glucose is broken down into two molecules of pyruvate in the cytoplasm. Once pyruvate is formed, it cannot directly enter the CAC, which occurs in the mitochondria.

To bridge this gap, pyruvate undergoes a transformation where it is decarboxylated, producing acetyl-CoA, carbon dioxide, and a molecule of NADH in the process. Acetyl-CoA is the key substrate that enters the CAC, allowing the cell to continue harvesting energy from the original glucose molecule. This step is crucial because it not only links glycolysis with the CAC but also sets the stage for further energy extraction through a series of enzymatic reactions in the cycle.

The other options do not represent this connection accurately. The formation of glucose pertains to gluconeogenesis, which is not a direct link to the CAC. Direct conversion of acetic acid does not occur; instead, acetyl-CoA (derived from pyruvate) enters the CAC. Generating ketone bodies is a separate metabolic pathway primarily related to fat metabolism and is not directly linked to the