beta oxidation/krebs cycle confusion

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beta oxidation/krebs cycle confusion

Post by TribeRugbyGirl » Wed Dec 07, 2005 8:27 pm

I am really confused on beta oxidation and the krebs cycle and how to caluclate the number of ATP, NADH, FADH2, O2, and CO2...

I know that in beta oxidation fats are broken down in mitochondria from acyl-CoA to Acetyl-CoA so it can enter in the Krebs many ATP are formed in beta oxidation...if given a 16 or 18 carbon molecule...more importantly than the answer how do you figure out what happens to this 18 carbon chain and the number of ATP, NADH, FADH2, O2 and CO2 that are produced.

Thanks (in advanced) for your help. :)

King Cobra
King Cobra
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Post by sdekivit » Wed Dec 07, 2005 9:27 pm

in each B-oxidation, 1 acetyl-CoA is produced, together with 1 NADH and 1 FADH2

--> thus each round in B-oxidation, the chain gets 2 shorter, resulting in 1 NADH and 1 FADH2 (and thus 4 ATP in the oxidative fosforylation)

remember that when we have a C18-chain we have 8 rounds of B-oxidation, resulting in 9 acetyl - CoA (the last round produces 2 acetyl CoA) together with only 8 NADH en 8 FADH2

thus for a C18-chain we get: 9 acetyl-CoA and 8 * 4 = 32 ATP

out of this acetyl-CoA is formed 3 * 9 = 27 NADH and 9 FADH2, resulting in 91 ATP, and 9 ATP from 9 GTP thus: 90 ATP

But to translocate the fatty acid, we use 2 ATP to form 2 ADP

thus the total yield of ATP of oxidation of a C18 is 120 ATP

the rest is easy now.

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