Question

Which of the following accurately summarizes the substrate-level phosphorylation strategy of ATP synthesis in glycolysis?

a. Electrons and hydrogen atoms are transferred to NAD+, which then transfers a phosphate to ADP to make ATP.
b. Phosphate groups are transferred exergonically from high-energy phosphorylated intermediates to ADP to make ATP.
c. Electrons are transported through a series of carriers to reduce substrates and drive the phosphorylation of ADP to ATP.
d. Energy from the sun is used to create a proton gradient that is used by an ATP synthase to phosphorylate ADP to ATP.

Answer 1

Substrate-level phosphorylation in glycolysis is a direct method of generating ATP by transferring a phosphate group from a phosphorylated intermediate to ADP, particularly during the catalytic conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate.

Step-by-step explanation:

The mechanism of substrate-level phosphorylation in glycolysis involves the transfer of a phosphate group from a high-energy phosphorylated intermediate directly to ADP, forming ATP. This process is catalyzed by enzymes known as kinases.

During glycolysis, an example of substrate-level phosphorylation is when 1,3-bisphosphoglycerate donates a phosphate to ADP, catalyzed by phosphoglycerate kinase, to form ATP. This conversion also involves the oxidation of the aldehyde group to a carboxyl group, transitioning 1,3-bisphosphoglycerate to 3-phosphoglycerate. This reaction occurs twice per glucose molecule, producing two ATPs in the process.