AP BIOLOGY

Detailed explanation-1: -The Krebs cycle starts with condensation of acetyl group with oxaloacetic acid (OAA) and water to yield citric acid. This reaction is catalysed by the enzyme citrate synthase and a molecule of CoA is released.

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. The Krebs cycle occurs in the mitochondrion of a cell (see Figure 6-1).

Detailed explanation-3: -What is true about the Krebs cycle? It occurs in the cytoplasm of the cell. It is an anaerobic process and thus does not require oxygen. It is the final stage of cellular respiration and produces the most ATP.

Detailed explanation-4: -In eukaryotes, the Krebs cycle reactions take place in the mitochondrial matrix, a dense solution that surrounds the mitochondria crests: in addition to water, the matrix contains all the enzymes necessary for the biochemical reactions of the cycle, coenzymes, and phosphates.