Question

Question 3

Glucose labeled with 14C in C-3 and C-4 is completely converted to acetyl-CoA via glycolysis and the pyruvate dehydrogenase complex. What percentage of the acetyl-CoA molecules

formed will be labeled with 14C, and in which position of the acetyl moiety will the 14C label be found? Select the correct answer and explain your reasoning

1. 100% of the acetyl-CoA will be labeled at C-1 (carboxyl).

2. 100% of the acetyl-CoA will be labeled at C-2.

3. 50% of the acetyl-CoA will be labeled, all at C-2 (methyl).

4. No label will be found in the acetyl-CoA molecules.

5. Not enough information is given to answer this question

Answer 1

The answer is that 50 per cent of acetyl co a will be labelled all at C 2. Glucose labelled with 14C is there in two parts. C 3 and C 4 so both will contribute equally and produce 50.