Which statement best describes the Krebs cycle?

Which statement best describes the Krebs cycle?

• A. The series of reactions in which pyruvate is broken down into carbon dioxide.
• B. The process by which photosynthesis occurs.
• C. The energy is captured in the form of ATP during glycolysis.
• D. Glycolysis step producing pyruvate directly.

Answer: (A)

The Krebs cycle is the stage in cellular respiration where the carbon atoms that came from glucose are fully oxidized to carbon dioxide in the mitochondria, while energy carriers NADH and FADH2 (and a small amount of ATP) are produced. Pyruvate from glycolysis is first converted to acetyl-CoA, and then acetyl-CoA enters the cycle to be oxidized to CO2. The idea captured by the statement is that CO2 is produced from the carbon units derived from pyruvate as part of this main oxidation process. The other descriptions refer to photosynthesis, glycolysis ATP production, or glycolysis producing pyruvate, which are not descriptions of the Krebs cycle itself.

The Krebs cycle is the stage in cellular respiration where the carbon atoms that came from glucose are fully oxidized to carbon dioxide in the mitochondria, while energy carriers NADH and FADH2 (and a small amount of ATP) are produced. Pyruvate from glycolysis is first converted to acetyl-CoA, and then acetyl-CoA enters the cycle to be oxidized to CO2. The idea captured by the statement is that CO2 is produced from the carbon units derived from pyruvate as part of this main oxidation process. The other descriptions refer to photosynthesis, glycolysis ATP production, or glycolysis producing pyruvate, which are not descriptions of the Krebs cycle itself.