Question

series of experiments in which 32P-labeled inorganic phosphate were introduced to erythrocytes (red blood cells) undergoing glycolysis. Would you expect to see the labeled phosphate in any glycolytic intermediates

Answer 1

The labeled inorganic phosphate will be found in 1,3-bisphosphoglycerate

Step-by-step explanation:

In the fifth reaction step of glycolysis, glyceraldehyde-3-phosphate is oxidized by the enzyme glyceraldehyde-3-phosphate dehydrogenase to 1,3-bisphosphoglycerate. Two molecules of NAD+ are reduced to form two NADH + 2H⁺. The energy released by the oxidation process is used to add an inorganic phosphate group to position 1 of two molecules of glyceraldehyde-3-phosphate to form two molecules of 1,3-biphosphoglycerate.

In the sixth step, the two molecules of 1,3-biphosphoglycerate are converted to 3-phosphoglycerate, with the high-energy phosphate group in position 1 added to ADP producing 2 ATP through substrate-level phosphorylation.

Since in the experiments,32-P-labelled inorganic phosphate were introduced to erythrocytes undergoing glycolysis, the inorganic phosphates would be expected to seen in the molecules of 1,3-biphosphoglycerate. However, since, the phosphate group is subsequently added to ADP to form ATP, it will no longer appear in other intermediates.