alleryStart learning →In alcohol fermentation, what is produced when a carboxyl group leaves pyruvic acid?
AEthanol and water together
BLactate and oxygen together
CCarbon dioxide and acetaldehyde
DAcetyl coenzyme A and hydrogen
Answer & Solution
Correct answer: C. Carbon dioxide and acetaldehyde
1. The first reaction of alcohol fermentation removes a carboxyl group from pyruvic acid.
2. That releases carbon dioxide as a gas.
3. Losing that carbon reduces the molecule by one carbon, making acetaldehyde.
4. Ethanol appears only in the second reaction, when acetaldehyde is reduced.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 7 "Cellular Respiration", section 7.5 Metabolism without Oxygen_
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