Question

Nitrogenous wastes are formed in the body because of the digestion of
A. Proteins
B. Carbohydrates
C. Fats
D. All of the above

Answer 1

Hint: The main nitrogenous waste produced in the body is Urea. Urea helps in the metabolism of compounds which contain Nitrogen.

Complete Answer:
The production of nitrogenous wastes occurs in Liver after the absorption of compounds containing Nitrogen in the intestine. The waste is excreted via Kidney with urine and other protein products also. The basic biomolecules present in our food are carbohydrates, proteins and lipids. Out of all this Nitrogen is present in proteins.
Amino acids contain nitrogen in the amino group and amino acids are the building blocks of proteins. Proteins are broken down into both nitrogenous and non- nitrogenous waste. Nitrogenous waste is Urea which is formed in the Urea Cycle that takes place in the liver.

Let us analyse the options to find the correct answer
Option A: Protein digestion contributes to nitrogenous waste. Hence, this is the correct option.
Option B: Carbohydrates do not contain nitrogen. Hence, this is the incorrect option.
Option C: Lipids are composed of fatty acids and glycerol. Hence, this is an incorrect option.
Option D: This is an incorrect option.

Thus, the correct answer is option A) proteins.

Additional Information:
- Urea cycle converts ammonia to Urea.
- Mammals like Humans are ureotelic animals because they excrete urea as their primary nitrogenous waste.
- Amphibians like fish also excrete urea.
- Nitrogenous waste produced in birds and reptiles is uric acid which is less toxic than urea.

Note: Nitrogenous wastes cannot be consumed by the body as they are toxic and hence need to be excreted out. The important nutrients from proteins are absorbed during digestion.