bigballer27

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In the absence of oxygen, oxidation of glucose produces which of the following products?

I. C02
II. H20
III. ATP


i picked I and III, because fermentation produces C02, and glycolysis produces ATP, but the answer is III only

why doesnt the C02 get factored in...are they referring to only the glycolysis cycle when they say oxidation of glucose, because i feel its kinda ambiguous, especially when they throw absence of oxygen in there (anaerobic), makes you think of pyruvate being broken down to C02 through fermentation

anyone?
 

loveoforganic

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Fermentation doesn't take place in people, the pyruvate is reduced to lactate. That's all I can think of
 

StIGMA

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CO2 is not generated until pyruvate (3C) loses a carbon and becomes acetyl CoA (2C).

Lactic acid (3C) fermentation is the alternative pathway in the absence of oxygen and does not produce CO2 (hence retaining its 3 carbons). I think H2O should also be included in the answer (2 phosphoglycerate to phosphoenolate generates water for glycolysis, and pyruvate to lactate does not utilize water).
 

bigballer27

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CO2 is not generated until pyruvate (3C) loses a carbon and becomes acetyl CoA (2C).

Lactic acid (3C) fermentation is the alternative pathway in the absence of oxygen and does not produce CO2 (hence retaining its 3 carbons). I think H2O should also be included in the answer (2 phosphoglycerate to phosphoenolate generates water for glycolysis, and pyruvate to lactate does not utilize water).

but to oxidize glucose, don't you need to regenerate NAD+, so i thought you can also run fermentation, because nowhere in the passage did it say anything about it being only in humans. it was about Oxidative phosphorylation in general, and looking in my book, fermentation DOES produce C02 as pyruvate is converted into ethanol

and yeah, now i agree that H20 should have been included too, what a dumb question
 

StIGMA

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In organisms that ferment pyruvate to ethanol, you obviously lose a carbon (ethanol is 2C). Unless ethanol fermentation is specifically mentioned, assume lactic acid fermentation. Note that both are referred to as fermentation, and the whole point of lactic acid fermentation is to also regenerate NAD+.
 
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bigballer27

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princeton review practice test #3 bio section