AP BIOLOGY

Detailed explanation-1: –In the very last stage where phosphoenolpyruvate is switched to pyruvate. The creation of ATP, by the transport of phosphate from an organic compound to ADP, is known as substrate-level phosphorylation. Hence, the correct answer is option (B).

Detailed explanation-2: -The last step in glycolysis is catalyzed by the enzyme pyruvate kinase (the enzyme in this case is named for the reverse reaction of pyruvate’s conversion into PEP) and results in the production of a second ATP molecule by substrate-level phosphorylation and the compound pyruvic acid (or its salt form, pyruvate).

Detailed explanation-3: -In the pay-off phase of glycolysis, a net of 2 ATP are produced by substrate-level phosphorylation.

Detailed explanation-4: -Substrate-level phosphorylation, which is a process of forming ATP by the physical addition of a phosphate group to ADP can take place in the cytoplasm during glycolysis or inside the mitochondrial matrix during the Krebs cycle.

Detailed explanation-5: -Substrate-level phosphorylation is the production of ATP from ADP by a direct transfer of a high-energy phosphate group from a phosphorylated intermediate metabolic compound in an exergonic catabolic pathway.