Question

Assertion: Respiratory pathway is an amphibolic pathway.
Reason: In respiration, there is a breakdown of many substances (catabolism) and synthesis of many substances (anabolism) by respiration intermediates.
A. Both assertion and reason are correct and the reason is the correct explanation of the assertion.
B. Both assertion and reason are correct but the reason is not the correct explanation of the assertion.
C. Assertion is correct but reason is incorrect.
D. Both assertion and reason are correct.

Answer 1

Hint: Respiration is the process of breaking down complex molecules into smaller compounds for the production of ATP. It involves the Krebs cycle or tricarboxylic cycle(TCA cycle). Respiration is important for the cell because it releases energy in the form of ATP that is necessary for the occurrence of all cellular reactions.

Complete answer: Amphibolic pathway refers to the pathway which involves both anabolisms which means synthesis and catabolism which means break down.
In the catabolic path-
Carbohydrates are broken down into glucose which is the main substrate of the respiratory pathway. Fats are also broken down into fatty acids and glycerol. These fatty acids later get converted to acetyl Co-A which is also a part of the respiratory pathway. Similarly, proteins are also converted to amino acids which enter respiration after deamination.
In the anabolic path-
Respiration not only includes breakdown but synthesis as well. When energy is needed acetyl Co-A gets into the process of respiration but when the body requires fatty acids or proteins, the acetyl Co-A holds the respiratory pathway and goes on to synthesize fatty acids. Also, the production of ATP is synthesis. This synthesis of fatty acids is an anabolic process.
Therefore, from the explanation, we can conclude that the assertion and reason both are correct and the reason is the correct explanation of the assertion.
So, the correct answer is “Option A”.

Note:
Respiration is of two types- Aerobic respiration and Anaerobic respiration.
Aerobic occurs in presence of oxygen and releases 38 ATP molecules with carbon dioxide and water as end products. Anaerobic respiration does not occur in presence of oxygen and releases 2 ATP molecules with lactic acid as the end product.