Question

Consider the following two equations A and B.
Equation A
Glucose $\to$ Pyruvate $\to C{O}_2+H_{2}O+$ Energy
Equation B
Glucose $\to$ Pyruvate $\to C_2{H}_{5}OH+C{O}_2+$ Energy
Which one of the following is correct with respect to both the equations A and B?

• A. A is aerobic respiration consisting of glycolysis and Krebs cycle, B is anaerobic fermentation reaction.
• B. A is anaerobic respiration and B is aerobic fermentation reaction.
• C. A is aerobic respiration B is anaerobic lactic acid fermentation.
• D. In both A and B reactions, pyruvate undergoes complete oxidation.

Answer 1

Answer: (A)

A is aerobic respiration consisting of glycolysis and Krebs cycle, B is anaerobic fermentation reaction.

In aerobic respiration, pyruvate formed at the end of glycolysis enters the TCA cycle and is completely oxidized to produce carbon dioxide, water, and energy in the form of ATP. In anaerobic alcoholic fermentation which is seen in yeast, glucose (sugar) is broken down into pyruvic acid which is then converted to ethanol due to lack of oxygen (anaerobic conditions). Therefore, the correct answer is option A.