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biochem q - biochem2
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07-03-2007, 04:05 PM
A person eats cookies made with coconut oil. The predominant fatty acid in the triglycerides contained in the coconut oil is lauric acid, which is a saturated 12-carbon fatty acid. Starting with free lauric acid within the mitochondria, what is the net energy yield in high-energy phosphate bonds from each molecule of lauric acid?
A. 83 B. 85 C. 95 D. 97 E. 110
07-03-2007, 04:30 PM
D 97 ATP . 12 C yield 6 acetyl coA which makes 72 ATP
5 NADH 15 ATP 5 FAD 10ATP is it like that????
07-03-2007, 04:30 PM
D. 95
From the 12C fatty acid we end up getting 6 molecules of Acetyl Co A. This produces a nett of 23 ATP. From each molecule of Acetyl co A, each turn of beta oxidation produces 12ATP. Therefore.. From oxidation 6x12=72 ATP Prior to oxidation to produce ACetyl Co A= 25 ATP Total is 95 ATP. or so i think. Where is this question from biochem2?
07-03-2007, 04:37 PM
sorry, my mistake, i think the nett production of ATP from breakdown for lauric acis bonds is only 23 ATP . some ATP is used for the conversion of FA to FA CoA by FA Co Synthetase right?
07-03-2007, 05:16 PM
The correct answer is C.Here is the calculation you need to perform.
Activation of the laurate requires two high-energy phosphate bonds as ATP is converted to AMP. The 12 carbon lauryl CoA is then split 5 times to produce 6 acetyl CoAs, and 5 ATPs (obtained from 1 FADH2 and 1 NADH), that are produced by each β-oxidation cycle. The resulting 6 acetyl CoA each produce 12 ATP equivalents (one is GTP, which is converted to ATP) when processed by the citric acid cycle. u were right lucid interval. this is from kaplan q bank. i was clueless abt it. ty for the explanaiton.
07-03-2007, 05:35 PM
i understand that 12C produces 6 acetyl co A and 72 ATPs. can u explain rest of the part.thnx
07-03-2007, 05:52 PM
For Beta Oxidation to begin the fatty acid must be converted to its corresponding Fatty Acyl Co A by the enzyme Fatty Aceyl Co A synthetase. This reaction requires the conversion of ATP to AMP utilizing 2 high energy bonds.
hence you have to subtract these 2 from the gross production of ATP which is 97 (from 6 actely co and 5 NADH and % FAHD2) hence 97-2= 95
07-03-2007, 06:20 PM
ok thnx lucid,thats how i ended up makin 97.thnx
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