Question

An amino acid that is basic in nature is:

• A. Lysine
• B. Valine
• C. Tryptophan
• D. Phenylalanine

Answer 1

Answer:

A. Lysine

Arginine, lysine, and histidine are all basic amino acids: Arginine: Has a guanidine group that can accept protons Lysine: Has an additional amine functional group that can accept protons Histidine: Has a heterocyclic imidazole side chain with a nitrogen atom that can acquire a positive charge These amino acids have basic side chains with a neutral pH. Their side chains contain nitrogen and resemble ammonia, which is a base. At physiological pH (about 7), the protonated forms of these amino acids predominate.