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#1
04-15-2011
 USMLE Forums Addict Steps History: Step 1 Only Posts: 102 Threads: 15 Thanked 86 Times in 50 Posts Reputation: 96
How many ATPs

Hello, hope someone can clear this up for me.
FA 2010 p.97...under...Glycolysis/ATP production: Aerobic metabolism of glucose produces 32 ATP via malate-aspartate shuttle or 30 ATP via glycerol-3-phosphate. I have looked at Kaplan LN and it says 36-38 (depending on the shuttle used)......but anyway, why the big number difference? What am i missing here? Thanks for your reply.

#2
04-15-2011
 USMLE Forums Scout Steps History: 1+CK+CS Posts: 37 Threads: 4 Thanked 37 Times in 14 Posts Reputation: 47

First Aid counts ATP as follows:
Glucose --> 2pyrovate: yielding 2 ATP and 2 NADH
these 2 NADH will produce 6 ATP if utilized through the malate-asp. shuttle.

2actyl CoA via Kreb's cycle will yield 24 ATP
so total production = 2+6+24 = 32 ATP

but they're missing the conversion of 2pyrovate to 2acetyl CoA which will yield 2NADH = 6 ATP which is then added to 32 to yield 38ATP as calculated in kaplan's notes
 The above post was thanked by: Triquetrum (04-16-2011)
#3
04-15-2011
 USMLE Forums Master Steps History: 1+CK+CS+3 Posts: 742 Threads: 137 Thanked 2,462 Times in 441 Posts Reputation: 2565

Also have a look at these two threads:
How many ATPs per Glucose Molecule
32 ATPs per glucose molecule?
 The above post was thanked by: noothan (04-15-2011)

#4
04-16-2011
 USMLE Forums Addict Steps History: Step 1 Only Posts: 102 Threads: 15 Thanked 86 Times in 50 Posts Reputation: 96

Thanks very much carisma_200x and Rasheed..
I noticed soon after posting that this q had already been asked in the forum.. Great help!

Quote:
 Originally Posted by carisma_200x First Aid counts ATP as follows: Glucose --> 2pyrovate: yielding 2 ATP and 2 NADH these 2 NADH will produce 6 ATP if utilized through the malate-asp. shuttle. 2actyl CoA via Kreb's cycle will yield 24 ATP so total production = 2+6+24 = 32 ATP but they're missing the conversion of 2pyrovate to 2acetyl CoA which will yield 2NADH = 6 ATP which is then added to 32 to yield 38ATP as calculated in kaplan's notes

 Tags Biochemistry-

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