Question

2) To study the fate of carbon during glycolysis under aerobic conditions, cultured cells are fed with 14C-glucose labeled in various positions. a) You use a radiolabeled form of glucose where the radioactive 14C occupies position 1.

Circle the correct statement and briefly explain your choice.

I. The carboxyl group of acetyl-CoA and CO2 become radiolabeled

II. The methyl group of acetyl CoA and CO2 become radiolabeled

III. The carbonyl group of acetyl-CoA becomes radiolabeled

IV. The methyl group of acetyl CoA becomes radiolabeled

V. CO2 becomes radiolabeled

VI. I don’t have enough information to conclude

b) You realize two independent experiments. In the first experiment, you use glucose where 14C occupies position 1. In the second experiments, 14C occupies position 2 and 6 in the glucose molecules. You use for each experiment 0.2 moles of radiolabeled glucose and you assume that all the pyruvate formed is converted to acetyl-CoA.

Circle the correct statements and explain your choices.

I. When glucose is labeled on carbon #1, 0.2 mole of acetyl-CoA is radiolabeled

II. When glucose is labeled on carbon #1, 0.1 mole of acetyl-CoA is radiolabeled

III. When glucose is labeled on carbons #2 and #6, 0.2 mole of acetyl-CoA is radiolabeled

IV. When glucose is labeled on carbons #2 and 6, 0.1 mole of acetyl-CoA is radiolabeled

V. When glucose is labeled on carbons #2 and 6, the carboxyl groups of half of the acetylCoA molecules are radiolabeled

VI. When glucose is labeled on carbons #2 and 6, the methyl groups of half of the acetyl-CoA molecules are radiolabeled