Essential amino acid is:: (A) Phenylalanine, (B) Proline, (C) Glutamine, (D) Serine
Answer is A. Phenylalanine It is an alpha-amino acid. This essential amino acid is classified as nonpolar because of the hydrophobic nature of the benzyl side chain. L-Phenylalanine (LPA) is an electrically neutral amino acid The codons for L-phenylalanine are UUU and UUC. Phenylalanine is a precursor for tyrosine, the monoamine signaling molecules dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline), and the skin pigment melanin.