Ammonium ions (NH4+) are always produced during intracellular digestion of which food molecule?
A. carbohydrate
B. fatty acid
C. glycerol
D. amino acid
E. polysaccharide
The correct answer and explanation is:
The correct answer is D. amino acid.
Explanation:
Ammonium ions (NH4+) are primarily produced during the breakdown of amino acids in intracellular digestion, especially in the process known as deamination. Deamination is the removal of the amino group (-NH2) from amino acids, which typically occurs in the liver.
Amino acids are the building blocks of proteins. When proteins are consumed and digested, their constituent amino acids are released into the bloodstream and taken up by various cells in the body for various functions. However, the body cannot store excess nitrogen, which is present in the amino group of amino acids. To deal with this, the amino group is removed from the amino acid molecule through the process of deamination.
The removal of the amino group results in the formation of ammonia (NH3), a toxic substance. Since ammonia is harmful to cells and tissues, it is quickly converted to ammonium ions (NH4+) in the body, which is less toxic than ammonia. These ammonium ions are then processed by the liver and excreted in the urine as urea, a much less toxic form of nitrogen waste, through the urea cycle.
The breakdown of carbohydrates, fatty acids, glycerol, and polysaccharides does not involve the direct production of ammonium ions. Instead, these macronutrients are broken down into glucose, fatty acids, and other intermediates, which do not contain nitrogen in the same way proteins do. Hence, they do not produce ammonia or ammonium ions during digestion.
In conclusion, the production of ammonium ions occurs during the metabolism of amino acids, and this process plays a critical role in nitrogen waste management within the body.