Question

The product obtained by the anaerobic respiration of yeast is
A. Lactic acid
B. Pyruvic acid
C. Ethanol
D. Acetic acid

Answer 1

Hint:- In the cytoplasm of the cell, anaerobic respiration takes place. In order to generate energy, most prokaryotes, including bacteria and archaea, rely on anaerobic respiration.

Complete Answer:-Anaerobic respiration does not require oxygen, unlike aerobic respiration. It is the release, in the absence of oxygen, of a comparatively limited amount of energy in the cells by the breakdown of food substances. During intense exercise, anaerobic respiration occurs in the muscles. Glucose is not entirely broken down, so it absorbs even less energy than it does during aerobic breathing. During physical activity, there is a build-up of lactic acid in the muscles.
In plant cells and certain microorganisms, anaerobic respiration also occurs. During fermentation and bread-making, anaerobic respiration of yeast is used. The alcohol used in alcoholic beverages like beer and wine is ethanol. In bread-making, carbon dioxide gas bubbles stretch the dough and make the bread flourish.

From these discussions we can conclude that Ethanol is produced by the anaerobic respiration of yeast.
Additional information:Yeast is used in food processing to cause fermentation and leavening. The fungi feed on sugars, contain alcohol (ethanol) and carbon dioxide; the former is the ideal commodity in beer and wine production, the latter in baking. Part of the carbon dioxide in sparkling wines and beer is preserved in the finished drink. When the dough is fried, the alcohol created in bread making is pushed off.Naturally occurring yeasts found in the air also start the fermentation of wine and sourdough breads. One yeast cell can ferment glucose per hour at approximately its own weight.

Therefore the correct answer is option (C).

Note:- Energy is also provided by anaerobic respiration. Anaerobic respiration generates less energy compared to aerobic respiration which does not require oxygen. Aerobic respiration releases 19 times more energy from the same amount of glucose than anaerobic respiration.