Biology molecular energetics

if a cell is able to synthesize 30 ATP molecules for each molecule of glucose completely oxidized to carbon dioxide and water, approximately how many ATP molecules can the cell synthesize for each molecule of private oxidized to carbon dioxide and water>
A. 8
B. 12.5
C. 16
D. 25

During oxidation of the pyruvate, a carboxyl group is eliminated from the pyruvate and released as CO₂.

Then the two carbon molecules oxidized produced in the first step and NAD+ accepts the electron and change into the NADH. The oxidized two carbon molecules attached to the coenzyme A and form acetyl CoA.

During the Krebs cycle, each molecule of the acetyl CoA OXIDIZES to generate ATP and carbon dioxide. This cycle produces 1 ATP, 1 FADH2, and 3 NADH. The total ATP production through this cycle is therefore around 12.

I do believe however 3 molecules of ATP are released when acetyl coA is formed so it would add up to 15 but I guess they are only considering from the Krebs cycle.

It technically should be 15 as two pyruvate is produced from 1 glucose therefore 15+15 = 30 or could be 32 ATP which is the value we learnt. So someone please clarify…

Does this help?


yess thank you so much! do you think we should know this much detail or more overall about this chapter? i haven’t seen questions about this chapter yet

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It’s all part of respiration which is part of the IMAT syllabus. Ari has made a great text lesson on it. I found it as a particularly difficult chapter to learn but there are ton of great videos online that helped me understand the products and reactants of each step!


I agree here, glucose is made of 2 pyruvates and each one generates exactly one half of the total ATP made. Therefore, should be 15:)