Which amino acid is a precursor for serotonin?

Tryptophan is the correct choice because it is an essential amino acid that serves as the primary precursor in the biosynthesis of serotonin, a neurotransmitter that plays a significant role in mood regulation and various physiological functions. The conversion of tryptophan to serotonin occurs through several enzymatic steps, starting with the hydroxylation of tryptophan to 5-hydroxytryptophan, which is then decarboxylated to form serotonin.

This relationship highlights how tryptophan consumption can influence serotonin levels in the body, which is why foods rich in this amino acid, such as turkey and bananas, are often associated with improvements in mood and relaxation. Understanding the biochemical pathways involving tryptophan helps to clarify its importance in mental health and neurotransmitter synthesis.