Ok AAMC? AAMC FL2 B/B #45

[sapientnarwhal]

So what the hell. This question asks for the amount of molecules of ATP that are produced. The question does NOT ask for the "net" ATP production. My first thought was 10 moles of ATP, but upon a closer examination of the question stem, I noticed that it did not mention "net" ATP production.
5 moles of glucose produces 20 moles of ATP and consumes 10 moles of ATP.
I thought AAMC was trying to trick me here.

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[verrager]

Just did AAMC FL2, had the EXACT same though process. Very frustrating

 

[mmchick]

Correct me if I've misunderstood where you diverged, but it is asking under anaerobic conditions, i.e. glycolysis, so net ATP production per glucose molecule would be 2.

5 glucose => 10 ATP

 

[sapientnarwhal]

Correct me if I've misunderstood where you diverged, but it is asking under anaerobic conditions, i.e. glycolysis, so net ATP production per glucose molecule would be 2.

5 glucose => 10 ATP

The question does not ask for net ATP production from anaerobic glycolysis. The question asks for # of ATP molecules produced. Technically 20 moles of ATP and 10 moles of ADP are produced from the anerobic catabolism of 5 moles of glucose via glycolysis.

 

[mmchick]

The question does not ask for net ATP production from anaerobic glycolysis. The question asks for # of ATP molecules produced. Technically 20 moles of ATP and 10 moles of ADP are produced from the anerobic catabolism of 5 moles of glucose via glycolysis.

Glycolysis would be the only process to proceed in anaerobic conditions, is my point. So given that, glycolysis produces 2 ATP per glucose molecule. Again, 5 glucose x 2 ATP = 10 ATP produced. I think you're misunderstanding the question.

 

[sapientnarwhal]

Glycolysis would be the only process to proceed in anaerobic conditions, is my point. So given that, glycolysis produces 2 ATP per glucose molecule. Again, 5 glucose x 2 ATP = 10 ATP produced. I think you're misunderstanding the question.

For 1 mole of Glucose
Hexokinase: 1 ATP => 1 ADP
PFK-1: 1 ATP => 1 ADP
Phosphoglycerate Kinase: 2 ADP => 2 ATP
Pyruvate Kinase: 2 ADP => 2 ATP

Net reactants: 2 ADP
Net products: 2 ATP
Moles ATP produced: 4
Moles ADP produced: 2

Because question did not ask for net ATP production, it is reasonable to answer based on the total moles of ATP produced, which is 4 per mole of glucose, and 20 for 5 moles of glucose. The fact that there is a net of 2 ATP does not necessarily mean that ONLY 2 moles of ATP are produced.

 

[westsidestoryz]

You have to reason why they would include the anaerobic portion on the question stem. You are right when you say that the TOTAL production of ATP is 20. But under anaerobic conditions (big hint to the "net" portion), its 10 ATPs. And it also states "consumption", which means the glucose has been converted all the way through glycolysis, so only a net of 10 ATPs remain.
Its tricky but they want to know the end-product, since all the glucose has been consumed.

 

[sapientnarwhal]

Whether it’s anaerobic or aerobic does not change the total amount of ATP produced from substrate level phosphorylation. “How many ... produced” is the major hint. They mention anaerobic to exclude the possibility that the 4 e- from 2 moles of NADH are shuttled into the ETC (just to clarify, there are a few pathways by which cytosolic NADH is “shuttled” into the mito). Instead we can assume that the NADH is expended in the reduction of pyruvate to lactate.