Question

In: Biology

11. Ethanol fermentation at a brewery is most likely limited by a. the availability of a...

11. Ethanol fermentation at a brewery is most likely limited by

a.

the availability of a carbohydrate source

b.

the availability of ATP

c.

the build up of carbon dioxide

d.

the build up of alcohol

e.

the availability of reductant

Expert Solution

11. Ethanol fermentation at a brewery is most likely limited by

Ans: (d) the build up of alcohol

Explanation:

a. the availability of a carbohydrate source: This option is not correct because the availability of the carbohydrate source is up to the brewery. What that essestially means is that if the use of more sugars yeilded more more alcohol, that would be done and it would not be the rate limiting step of the entire process.

b. the availability of ATP: Fermentation is a process that yeilds ATP. If we take glucose as an example, it first undergoes glycolysis to for pyruvate and then fermentation to form ethanol, CO2 and ATP. While in normal conditions when yeast undergoes regular aerobic respiration, the availability of ATP would stop the process as the yeast would no longer require fermentation process to survive, in a brewery they are forced to be in anaerobic conditions because they will only produce alcohol in anaerobic contitions. Hence, this step is not the rate limiting step either.

c. the build up of carbon dioxide: Carbon dioxide is a gas and it escapes the solution once produced. Since the yeast were already in anaerobic condition to begin with, they are not affected by CO2 build up. Thus, this is also not the answer.

e. the availability of reductant: There are no non-organic reductants in the process of alcoholic fermentation. Hence this option is the most incorrect.

d. the build up of alcohol: This is the rate limiting step mainly because at higher alcoholic percentages, the yeast would not be able to survive. This is the reason why distillation is necessary to make alcoholic liquors and fermentation alone is not enough.

gladiator answered 2 years ago

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