AP BIOLOGY

Detailed explanation-1: -The three-carbon pyruvic acid molecules are converted to a two-carbon molecule attached to Coenzyme A, called acetyl CoA, via the process of pyruvate oxidation. It is the product, acetyl CoA, which enters the Krebs cycle.

Detailed explanation-2: -The Krebs cycle uses the two molecules of pyruvic acid formed in glycolysis and yields high-energy molecules of NADH and flavin adenine dinucleotide (FADH2), as well as some ATP.

Detailed explanation-3: -Answer and Explanation: The molecules that can enter the Krebs or Citric Acid cycle are Acetyl CoA. Acetyl CoA is made in an intermediate step between glycolysis and the Krebs cycle.

Detailed explanation-4: -Instead, the pyruvic acid breaks down to acetylcoenzyme A, which enters the Krebs cycle and the electron transport system and is eventually processed to form water plus carbon dioxide plus a large amount of ATP.