Question

Select the incorrect statement with respect to the given representation.

A. X is the enzyme pyruvate dehydrogenase and Y is the enzyme ethanol decarboxylase
B. This process is involved in the brewing industry for producing beverages like beer, rum, whisky etc.
C. Accumulation of the end product (i.e ethanol) during this process, in a culture of yeast, stops the multiplication of yeast cells and may even lead to death of cells.
D. None of these

Answer 1

Ethanol fermentation, also called alcoholic fermentation, is a biological process that converts sugars such as glucose, fructose, and sucrose into cellular energy, producing ethanol and carbon dioxide as by-products. Alcoholic fermentation is considered an anaerobic process.

Step by step answer: In the above reaction X is the enzyme pyruvate decarboxylase and Y is the enzyme ethanol dehydrogenase. The production of alcohol(ethanol) occurs best in the absence of oxygen. However, from the yeast's point of view, alcohol and carbon dioxide are waste products, and as the yeast continues to grow and metabolize in the sugar solution, the accumulation of alcohol will become toxic when it reaches a concentration between 14-18%, thereby killing the yeast cells. This is the reason why the percentage of alcohol in wine and beer can only be approximately 16%.
In order to produce beverages (liquor) with higher concentrations of alcohol, the fermented products must be distilled.
Hence, the correct answer is option A

Note: Ethanol fermentation causes bread dough to rise. All ethanol contained in alcoholic beverages (including ethanol produced by carbonic maceration) is produced by means of fermentation induced by yeast.