How much ATP/NTP do you get from Anerobic/ Aerobic Respiration?

[PremedSurvivor]

NTPs are basically a general term for ATP, GTP etc.
Alright so in TBR Bio Book II, Chapter VIII, Passage I:

Question 2 points out that if oligomycin (ATPase inhibitor) is added, you get only 2 NTP from substrate-level phosphorylation because the cell can no longer rely on aerobic respiration and switches to anaerobic respiration.

THEN, in Question 3, TBR says that with oligomycin & 2,4-NDP (decouples the electron transport chain), you get 4 NTP because you get 2 ATP from glycolysis and 2 GTP from Krebs.

Why wasn't the calculation from Krebs included in question 2? Which is it? And I thought the Krebs cycle was considered an aerobic process?

Can someone please sum up the net gains from Glycolysis (anaerobic), Krebs, and the ETC??

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[Captain Sisko]

NTPs are basically a general term for ATP, GTP etc.
Alright so in TBR Bio Book II, Chapter VIII, Passage I:

Question 2 points out that if oligomycin (ATPase inhibitor) is added, you get only 2 NTP from substrate-level phosphorylation because the cell can no longer rely on aerobic respiration and switches to anaerobic respiration.

THEN, in Question 3, TBR says that with oligomycin & 2,4-NDP (decouples the electron transport chain), you get 4 NTP because you get 2 ATP from glycolysis and 2 GTP from Krebs.

Why wasn't the calculation from Krebs included in question 2? Which is it? And I thought the Krebs cycle was considered an aerobic process?

Can someone please sum up the net gains from Glycolysis (anaerobic), Krebs, and the ETC??

Bear with me since I'm on a phone.

The tca cycle doesn't actually require oxygen, but the etc does. What happens is that if the etc is stopped, its reactants, namely nadh and fadh2, will accumulate, feeding back and turning off the cycle. Lactate can then get made for anaerobic respiration.

The question you're asking has to do with the internals of the etc itself. Atp generation is coupled to reduction of nadh and fadh2, so if you turn off atp synthase, nadh and fadh2 are going to build up. However if you decouple atp synthesis from reduction, nadh and fadh2 can still be reduced without making additional atp, and since your electron carriers don't back up, tca can keep going. So you get 2 atp from glycolysis and 2 gtp from tca.

Fun fact, if you temporarily decouple the etc you have a weight loss drug!

I probably got a couple minor details wrong but that's the gist. It's probably beyond the scope of mcat though.

 

[pacer]

During ETC, the NADH and FADH^2 from glycolysis, pyruvate dehydrogenase complex and Kreb's Cycle are converted into ATP by creating a proton (H+) gradient across the mitochondrial inner membrane and coupling the highly spontaneous flow of H+ back into the mitochondrial matrix along its concentration gradient with the highly unfavorable reaction of ATP synthesis. So, if ETC is disrupted and can not occur, there will be a decrease in the amount of ATP made because the NADH and FADH^2 will not get converted into ATP. So the answer is correct that you will only have 2 NTP from glycolysis and 2 NTP from Kreb's Cycle. The rest come from the conversion of high energy electron carriers during ETC which in this case is not able to occur.