Need help calculating ATP

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ayi
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Need help calculating ATP

Post by ayi » Mon Oct 04, 2010 3:29 am

How do you calculate the atp in 80 carbon fat in fatty acid party of the molecule? Can someone please break it down for me?

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JackBean
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Post by JackBean » Mon Oct 04, 2010 10:27 am

you mean fatty acid, which has 80 carbons? Whau!

Well, I think you would get NO energy from that, because any enzyme wouldn't be able to digest that :lol: Anyway, what you probably want and need to hear is that you run 39-times the beta-oxidation (you have 80 carbons /2 = 40, but the last acetyl-CoA is released already in 39. cycle), so calculate, how many NADHs and FADH2s will you get ;) And subsequently you have 40 acetyl-CoAs which go to TCA cycle and are degraded to CO2 and H2O ;)
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

ayi
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Post by ayi » Mon Oct 04, 2010 1:57 pm

Can you totally break it down for me? Sorry, I am not a microbiology major and it doesn't explain it very well in my text book.

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JackBean
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Post by JackBean » Tue Oct 05, 2010 11:11 am

OK, well, the fatty acids are broken down in beta-oxidation
http://en.wikipedia.org/wiki/Beta_oxidation

in this process, you always get off 2 carbons in the form of acetyl-CoA, so after one cycle you will have 78 carbons, after 2 cycles it's 76 carbons, after 3 cycles 74 carbons etc. etc. up to 38th cycle you get 4 carbons, which are split appart in 39th cycle (there's some calculation also on the Wiki). So, you end up with 39 cycles and 40 acetyl-CoAs.
In each cycle you get 1 NADH and 1 FADH2, each giving let's say 2.5 and 1.5 ATP respectively. So you have 39 NADHs and 39 FADH2s, so calculate the ATPs.
Well, the 40 acetyl-CoAs enter the TCA cycle
http://en.wikipedia.org/wiki/Citric_acid_cycle
in one cycle you get 1 ATP (equivalent of GTP), 3 NADHs, one FADH2 and 2 CO2
http://en.wikipedia.org/wiki/Citric_acid_cycle#Products
so, you end up with 40 ATPs, 120 NADHs, 40 FADH2 and you don't care about the CO2 (otherwise 80;).
Now just calculate, how many ATPs you get and sum with the previous ones ;)
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

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