Which molecule is produced from pyruvate during the prep stage to enter the Citric Acid Cycle?

Which molecule is produced from pyruvate during the prep stage to enter the Citric Acid Cycle?

• A. Oxygen
• B. NADH
• C. Acetyl CoA
• D. CO2

Answer: (C)

The prep stage converts pyruvate into acetyl-CoA. In mitochondria, each pyruvate is decarboxylated and attached to CoA, forming acetyl-CoA, while CO2 is released and NAD+ is reduced to NADH. This acetyl-CoA then enters the Citric Acid Cycle by combining with oxaloacetate to form citrate, supplying the cycle’s substrate. Oxygen isn’t produced in this step, and NADH is made here but it goes on to fuel the electron transport chain rather than enter the Citric Acid Cycle. CO2 is released as a waste product and does not feed the cycle. The molecule that actually feeds the CAC is acetyl-CoA.

The prep stage converts pyruvate into acetyl-CoA. In mitochondria, each pyruvate is decarboxylated and attached to CoA, forming acetyl-CoA, while CO2 is released and NAD+ is reduced to NADH. This acetyl-CoA then enters the Citric Acid Cycle by combining with oxaloacetate to form citrate, supplying the cycle’s substrate.

Oxygen isn’t produced in this step, and NADH is made here but it goes on to fuel the electron transport chain rather than enter the Citric Acid Cycle. CO2 is released as a waste product and does not feed the cycle. The molecule that actually feeds the CAC is acetyl-CoA.