destroyer question 274 2011 version

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xtra333

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hello users of sdn,
I have a question on destroyer 2011 version bio section. which statement is false?
lactate is produced in a fatigued muscle.
fermentation utilizes the reactions of glycolysis to produce ethanol anaerobically.
Under aerobic conditions, most of the pyruvate from glycolysis is oxidized by the krebs cycle.
actively contracting muscle has a high rate of pyruvate formation
In yeast cells that grow anaerobically, pyruvate is converted into ethanol

I thought the second statement is false because to produce ethanol, the reactions of alcohol dehydrogenase are different than the reactions of glycolysis.

But the answer key says that "actively contracting muscle" statement is false. I understand that contracting muscle needs more ATP, so they can get the ATP by glycolysis. Also, the answer key says that lactate formation is high in contracting muscle. However, is not pyruvate a by product for lactate formation ? Therefore, compared to normal cells, I believe contracting muscle should have a higher rate of pyruvate formation.
 
Lactate (and Ethanol) is made from Fermentation (Anaerobic). Pyruvate is not a byproduct of lactate. Pyruvate is used either for Alcohol fermentation, lactate fermentation, or for the Krebs cycle for aerobic respiration. Fermentation is anaerobic so that is why lactate is high in contracting muscles to make fast ATP (glycolysis makes ATP faster and causes lactate buildup in muscles.)
 
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