Which amino acid is listed as the most abundant protein in the body and used in many processes?

• A. Glutamine
• B. Lysine
• C. Valine
• D. Methionine

Answer: (A)

Glutamine is the most abundant free amino acid in the body and serves as a major nitrogen donor and energy source in many tissues. It fuels synthesis of nucleotides and amino sugars, supports the function of rapidly dividing cells like those in the gut lining and immune system, and helps maintain acid–base balance by releasing ammonia and generating bicarbonate. This combination of high abundance and broad involvement in multiple essential processes is why glutamine is highlighted as the most abundant amino acid used in many physiological roles. The other amino acids listed are important for specific functions, but they don’t match glutamine’s widespread presence and versatility.