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    anaerobic respiration in yeast

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    Step 1 of anaerobic respiration in yeast provides chemical energy in the form of ATP. Step 2 (alcaholic fermentation) produces no further energy;
    however it is essential for anaerobic respiration to continue. Explain why this is the case, in a few sentances.

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    © BrainMass Inc. brainmass.com December 24, 2021, 8:58 pm ad1c9bdddf
    https://brainmass.com/biology/anaerobic-respiration/anaerobic-respiration-yeast-331402

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    ANSWER:
    Generation of ATP during anaerobic metabolism is accomplished through glycolysis. For every mole of glucose that enters the glycolytic pathway, 2 moles of ATP are generated. The pyruvate, which is the end product of glycolysis then proceeds to alcoholic fermentation to produce ethanol and carbon dioxide in a 2-step process shown below:
    Pyruvate CO2 + acetaldehyde

    Ethanol + NAD+
    The fermentation step does not produce additional ATP for the cell. However, it is important that pyruvate proceeds to fermentation during anaerobic metabolism for the purpose of regenerating the NAD+ (reaction 2 of fermentation). The concentration of NAD+ in the cytosol of the cell is very limiting. NAD+ is important because it is used in glycolysis (reaction 6 of glycolysis as catalyzed by glyceraldehydes-3-phosphate dehydrogenase). Glycolysis is the main energy-producing pathway of the cell during anaerobic conditions. Hence, it must keep going. But once NAD+ is depleted, glycolysis will eventually stop, and the cell will not be able to generate ATP to fuel its metabolic needs. This will lead to the eventual death of the cell. Hence, fermentation is a mechanism of ensuring that NAD+ is continuously replenished. Thus, the cell goes through it, although from the standpoint of energy generation, it does not get additional ATP from it.

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    © BrainMass Inc. brainmass.com December 24, 2021, 8:58 pm ad1c9bdddf>
    https://brainmass.com/biology/anaerobic-respiration/anaerobic-respiration-yeast-331402

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