36ATP or 38ATP?

[Hopeful20]

Could someone please clarify whether or not we produce 36ATP per glucose or 38ATP/glucose during aerobic respiration?

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[ToZanarkand]

It is 36 ATPs.

 

[MrWilson]

From what I can remember, it's 36 ATP for eukaryotes, and 38 ATP for prokaryotes.

 

[tvndental]

In truth it could be both. Depends on which shuttle that is used to transport the electrons that you get from glycolysis into the mitochondria. If malate-aspartate shuttle is used then you get 38 ATP (trades cytoplasmic NADH for mitochondrial NADH). If you use the phosphero-glycerol shuttle you get 36 ATP (trades cytoplasmic NADH for mitochondrial FADH2). NADH yields ~ 3 ATP thats why you get 38 if you use the malate shuttle. FADH2 yields ~ 2 ATP thats why you get 36 if you use the phosphero-glycerol shuttle.

Also the membrane of the mitochondria in some cells can be leaky to H+ and not leaky. So you cant really predict how much ATP really comes out of aerobic respiration. But that is something you shouldn't worry about for the DAT. (I'm a bio major)

If the question is asked then I think it is safe to say to assume 36 ATP.

 

[jirotrom]

Cardiac muscle and one other muscle in the body makes 38ATP because they shuttle 3 NADHs instead of 2, normal skeletal muscle is about 36

 

[tvndental]

Cardiac muscle and one other muscle in the body makes 38ATP because they shuttle 3 NADHs instead of 2, normal skeletal muscle is about 36

It is cause they use different shuttles. Skeletal Muscle use primarily the phosphero-glycerol shuttle.

 

[blinktonheim]

if you really want to get technical and use 2 sig figs the number is 30 ATP
(2.5 ATP per NADH, 1.5 ATP per succinate)

at least that is what our biochem teacher taught

 

[tvndental]

if you really want to get technical and use 2 sig figs the number is 30 ATP
(2.5 ATP per NADH, 1.5 ATP per succinate)

at least that is what our biochem teacher taught

The thing is that there is no absolute number. Maybe averages but no absolute number of ATP per anything because the amount of ATP depends on the flow of H+ into ATP synthase which is affected by many factors. The mitochondria can be leaky and let H+ flow out. Not all membranes are the same. Not all are as fluid as the other. Also depending on the tissue. The shuttle used to ship the NADH from glycolysis will be different.

 

[OU11BB]

The thing is that there is no absolute number. Maybe averages but no absolute number of ATP per anything because the amount of ATP depends on the flow of H+ into ATP synthase which is affected by many factors. The mitochondria can be leaky and let H+ flow out. Not all membranes are the same. Not all are as fluid as the other. Also depending on the tissue. The shuttle used to ship the NADH from glycolysis will be different.

Which is exactly why i dont think there will be a "how many ATP total" questions. It should be fairly obvious if it is.

 

[blinktonheim]

i agree, that question would be way too vague, unless the choices were like
A)100 B)36 C)8 etc.

 

[crew09]

the Princeton Hyperlearning book mentions that older texts say 36-38 while the newer more accurate count is 30-32.

Wikipedia has a cited source that supports this:

Biology textbooks often state that 38 ATP molecules can be made per oxidised glucose molecule during cellular respiration (2 from glycolysis, 2 from the Krebs cycle, and about 34 from the electron transport system).[2] However, this maximum yield is never quite reached due to losses (leaky membranes) as well as the cost of moving pyruvate and ADP into the mitochondrial matrix and current estimates range around 29 to 30 ATP per glucose.[2] Aerobic metabolism is 19 times more efficient than anaerobic metabolism (which yields 2 mol ATP per 1 mol glucose).

http://en.wikipedia.org/wiki/Cellular_respiration#cite_note-Rich-1

I guess my question would be if DAT exam constructors rely on older texts or not...