Which statements describe the Krebs cycle as presented?

Which statements describe the Krebs cycle as presented?

• A. Pyruvic acid combines with acetyl CoA to form citric acid
• B. Hydrogen is removed from citric acid
• C. Carbon dioxide is produced
• D. All of the above

Answer: (D)

In the Krebs cycle, the acetyl group from acetyl-CoA is oxidized to CO2 in the mitochondrial matrix, while energy carriers NADH and FADH2 are produced to drive the electron transport chain. The cycle begins with acetyl-CoA combining with oxaloacetate to form citrate, and the acetyl group ultimately comes from pyruvate after it is converted to acetyl-CoA—so describing citrate formation reflects what happens when entering the cycle. Hydrogen is removed from intermediates as they are oxidized, transferring to NAD+ and FAD to make NADH and FADH2, and carbon dioxide is released during decarboxylation steps. Since all these events occur in the Krebs cycle, the combined description is correct.

In the Krebs cycle, the acetyl group from acetyl-CoA is oxidized to CO2 in the mitochondrial matrix, while energy carriers NADH and FADH2 are produced to drive the electron transport chain. The cycle begins with acetyl-CoA combining with oxaloacetate to form citrate, and the acetyl group ultimately comes from pyruvate after it is converted to acetyl-CoA—so describing citrate formation reflects what happens when entering the cycle. Hydrogen is removed from intermediates as they are oxidized, transferring to NAD+ and FAD to make NADH and FADH2, and carbon dioxide is released during decarboxylation steps. Since all these events occur in the Krebs cycle, the combined description is correct.