Hi Lydia,

Could you provide the question number for reference?

Thank you!

Katt

Hi Lydia,

I've drawn a picture of how proton transport through the ETC works:

https://ibb.co/25TppRy

In addition, it takes 3 H+ to make 1 ATP by ATP sythase on average, so you can always take the amount of ATP made per molecule if you know that and multiply it by three.

This is a question that can come up on the topic of oxidative phosphorylation. It is a little more advanced than the coverage in the CC.

Hope this helps!

Katt

Hi Lydia,

I'm not sure I understand this question - can you clarify as to where are you getting the 4 ATP from?


NADH is generated through the steps of glycolysis, and only really produces ATP when it goes through the ETC for aerobic respiration. It produces 2.5 ATP per NADH that enters the ETC. I would count any other ATP formed seperately from that of NADH.

Please let me know if I have misunderstood your question.

Katt

Hi Lydia,

I understand what you are getting at now, my mistake. The NADH produced in glycolysis requires 1 ATP/NADH to get transported into the mitochondrial matrix. This cost of getting into the matrix is deducted from the ATP it would produce in the ETC so you get 2 NADH producing 6 ATP, but you then subtract the 2 ATP you used to get them in there.

The Krebs cycle is already inside of the mitochondria and so does not have this same consideration.

Note that this is not a problem for the initial question as it is fair to assume all the NADH was already in the mitochondrial matrix.

Please let me know if this is unclear!

Katt