AP BIOLOGY

Detailed explanation-1: -The cycle continues in the presence of different enzymes through the production of different intermediates and the release of carbon dioxide and water as end products. So, the correct answer is, ‘Citric acid’.

Detailed explanation-2: -Overview of the Krebs or citric acid cycle, which is a series of reactions that takes in acetyl CoA and produces carbon dioxide, NADH, FADH2, and ATP or GTP.

Detailed explanation-3: -Answer and Explanation: The Krebs cycle produces three molecules of NADH, one molecule of FADH2, and one molecule of GTP as energy molecules and two carbon dioxide molecules during one cycle.

Detailed explanation-4: -Answer and Explanation: Oxaloacetate is an intermediate of the Krebs cycle but not an end product of the cycle. Oxaloacetate is catalyzed by the enzyme known as citrate synthase and produces citrate with the reaction of acetyl coenzyme A.