Question

Which option correctly describes glucose catabolism?

1. Glucose is broken down in glycolysis, yielding two ATP molecules; after the Krebs cycle, 34 molecules of ATP are formed in ETS reactions.

2. Glucose is broken down in glycolysis, yielding pyruvic acid; after the Krebs cycle, two molecules of ATP are formed in ETS reactions.

3. Glucose is broken down in glycolysis, yielding two ATP; after the Krebs cycle, NADH and FADH2 are formed, yielding NAD+ and FAD in ETS reactions.

4. Glucose is broken down in glycolysis, yielding pyruvic acid; after the Krebs cycle, NADH and FADH2 are formed, yielding 34 ADP in ETS reactions.

Answer 1

It's number 1, I'm positive

Answer 2

The right answer is 1.

We will consider here the catabolism of a glucose molecule by glycolysis and the Krebs cycle, without taking into account the associated pathways.

* Assessment of glycolysis: formation 6 ATP in theory (5 ATP actually).

* Assessment of the catabolism of pyruvate: formation of 3 ATP per molecule of pyruvate in theory (2.5 in reality) and therefore of 6 ATP in theory (5 ATP in reality) for a molecule of glucose.

* Review of the Krebs cycle (associated with ETS reactions) : theoretically 12 ATP per molecule of acetylcoenzyme A (10 ATP in reality) and thus in theory 24 ATP (20 ATP actually) for a molecule of glucose.

The overall theoretical balance is therefore 36 ATP (some books says 38) (30 ATP actually).