NADH FADH2 problem

[sbesbesbe]

Hi there SDN

this is very frustrating....
Some books (Cliff's AP biology) is using
1 NADH = 3 ATP
1 FADH2 = 2 ATP

while some books (including my biochem class) is using
1 NADH = 2.5 ATP
1 FADH2 = 1.5 ATP

Chad used
1 NADH = 2.5 ATP
1 FADH2 = 1.5 ATP in the videos BUT used
1 NADH = 3 ATP
1 FADH2 = 2 ATP for the quizzes! argghh

which one should i go with? I leaning towards
1 NADH = 3 ATP
1 FADH2 = 2 ATP since this is from cliff's AP biology.

Isn't this a problem since on DAT, apparently they have asked in the past to calculate number of ATP yield...

Which one is right?
Thanks!

---

Members don't see this ad.

 

[Josh779]

I would imagine they would give you the numbers they want you to use. At least that is what I have encountered on practice tests.

 

[sbstrat27]

Hi sbesbesbe,

The question you are asking has to do with how NADH made during glycolysis (in the cytoplasm) is transported into the mitochondrion for oxidative phosphorylation. It takes 1 ATP per NADH to shuttle it into the mitochondrion. Prokaryotes lack mitochondria, so they do not need this extra expenditure of energy per molecule of NADH formed from glycolysis. This distinction of NADH FROM GLYCOLYSIS is important, since the NADH yielded from pyruvate decarboxylation and the Krebs cycle remains at 3 ATP/NADH. These NADH are synthesized within the mitochondrion, and thus do not require an energy expenditure for transport. The yield for FADH2 is 2 ATP per molecule. Some books try to keep track of the ATP's without considering the shuttle while some do. Others try to average the values. Though there is still much research on the matter, the most accepted breakdown of the ATP yield is:

Per glucose molecule in eukaryotes

Glycolysis:
Substrate level phosphorylation- 2 ATP
2 NADH x 2 ATP (3 ATP in prokaryotes) /NADH= 4 ATP (6 ATP in prokaryotes)

Pyruvate Decarboxylation:
2 NADH x 3 ATP/NADH= 6 ATP

Krebs Cycle:
6 NADH x 3 ATP/NADH= 18 ATP
Substrate level phosphorylation- 2 ATP
2 FADH2 x 2 ATP/FADH2= 4 ATP

Total = 36 ATP (38 ATP in prokaryotes)

 

[sbesbesbe]

Hi sbesbesbe,

The question you are asking has to do with how NADH made during glycolysis (in the cytoplasm) is transported into the mitochondrion for oxidative phosphorylation. It takes 1 ATP per NADH to shuttle it into the mitochondrion. Prokaryotes lack mitochondria, so they do not need this extra expenditure of energy per molecule of NADH formed from glycolysis. This distinction of NADH FROM GLYCOLYSIS is important, since the NADH yielded from pyruvate decarboxylation and the Krebs cycle remains at 3 ATP/NADH. These NADH are synthesized within the mitochondrion, and thus do not require an energy expenditure for transport. The yield for FADH2 is 2 ATP per molecule. Some books try to keep track of the ATP's without considering the shuttle while some do. Others try to average the values. Though there is still much research on the matter, the most accepted breakdown of the ATP yield is:

Per glucose molecule in eukaryotes

Glycolysis:
Substrate level phosphorylation- 2 ATP
2 NADH x 2 ATP (3 ATP in prokaryotes) /NADH= 4 ATP (6 ATP in prokaryotes)

Pyruvate Decarboxylation:
2 NADH x 3 ATP/NADH= 6 ATP

Krebs Cycle:
6 NADH x 3 ATP/NADH= 18 ATP
Substrate level phosphorylation- 2 ATP
2 FADH2 x 2 ATP/FADH2= 4 ATP

Total = 36 ATP (38 ATP in prokaryotes)

Thanks for your response
so on the DAT, these values will probably be given?