Question

In alcoholic fermentation, $CO_2$ is evolved during
A)Decarboxylation of pyruvic acid
B)Formation of acetaldehyde
C)Oxidation of acetaldehyde
D)Both A and B

Answer 1

Hint: Fermentation is a metabolic process in which energy is extracted from carbohydrates under anaerobic conditions. It is used to make alcohol.

Complete answer:
Alcoholic fermentation, commonly called ethanol fermentation is a biologic process in which sugars like sucrose, fructose and glucose are converted into cellular energy, producing carbon dioxide and ethanol as by-products. This is a two step process in which the first step involves the conversion of glucose (6-carbons) into pyruvate (3-carbons) via glycolysis and the second step involves the conversion of pyruvate into ethanol (2 carbons) and carbon dioxide (1-carbon) with the help of a molecule of NADH.

Now, let us look at each step one by one.
Decarboxylation of pyruvic acid leads to the production of acetaldehyde by the removal of a carbon dioxide molecule. The acetaldehyde formed can then be hydrogenated to form ethanol. This is an important part of step 2 of alcoholic fermentation. Therefore, this is a relevant option.

Formation of acetaldehyde takes place by decarboxylation of pyruvic acid which leads to the release of carbon dioxide, Therefore, this is a relevant option.

Oxidation of acetaldehyde leads to the formation of acetic acid. This process does not evolve carbon dioxide. Therefore, this option is incorrect.

Since the options (A) and (B) are relevant, therefore, both (A) and (B) is the correct option.

Hence, the correct answer is option (D)

Note: Glycolysis, the step 1 of the alcohol fermentation process is a 10-step metabolically essential process which converts a single molecule of glucose into two molecules of pyruvate. This process results in the formation of ATP and NADH which are energy rich molecules used for the catalysis of several crucial steps in the different metabolic pathways in the body.