Question

Ammonia is the end product of
A) Glucose breakdown
B) Fatty acid metabolism
C) Protein metabolism
D) Breakdown of biogenic amines

Answer 1

Hint: As the end product of protein metabolism (transamination and deamination), ammonia is continuously emitted. It is toxic to the body. So, it is detoxified in the liver of the animals.

Complete answer:
Ammonia is detoxified to form urea by the ornithine cycle. Urea, relatively, is quite less in toxicity than ammonia. Thus, it can remain inside the body for longer durations, without being harmful.
Dietary protein intake also has significant effects on the metabolism of ammonia.

>Option A) Glucose breakdown - In the aerobic respiration, glucose from the food is completely broken down into - water and carbon dioxide, by oxidation. Thus, this option is incorrect.
>Option B) Fatty acid metabolism - Fatty acid degradation converts an aliphatic compound into activated acetyl units (Acetyl CoA to Acetyl Coenzyme A). This can be further processed by the citric acid cycle.
Thus, this option is incorrect.
>Option C) Protein metabolism - In general, high-protein diets, specifically high in sulfur-containing amino acids - increase the acid production - simultaneously causing an increase in ammonia excretion, while, low-protein diets decrease the excretion of ammonia.This is the correct option.
>Option D) Breakdown of biogenic amines happens in presence of alcohol as it can increase absorption rate. Monoamine oxidase is an enzyme which helps in breaking down biogenic amines. This option is incorrect.

Note:In the human body, Urea is the largest circulating pool of nitrogen. Hypokalemia and glucocorticoids can alter the transport of urea as well as ammonia. These conditions also have an impact on the protein metabolism.