Examine the peptide. Peptide with three amino acid residues. The first residue contains a methyl group side chain. The second residue contains a hydrogen atom side chain. The third residue contains a hydroxymethyl group side chain. The amino group of the first side chain binds to the unshown remainder of the peptide. The carboxyl group of the third side chain binds to the unshown remainder of the peptide. Determine which amino acids are present in the peptide.

The peptide is composed of Alanine, Glycine and Serine and is written in shorthand as: Ala-Gly-Ser.

Explanation:

Amino acids contain an α-carboxyl group, an α-amino group, and an R side chain which distinguishes one amino acid from another.

Peptides are chains of amino acids which are covalently bonded together through substituted amide linkages known as peptide bonds. The reaction occurs between an amino group of one amino acid and the carboxyl group of another amino acid with the removal of a water molecule.

A tripeptide is a peptide composed of three amino acids linked together by peptide bonds.

In the given peptide, the first residue contains a methyl group side chain. The second residue contains a hydrogen atom side chain. The third residue contains a hydroxymethyl group side chain.

The amino acid that contains a methyl group side chain is Alanine (Ala).

The amino acid that contains a hydrogen atom side chain is Glycine, Gly.

The amino acid that contains a hydroxymethyl group side chain is Serine, Ser.

Therefore, the peptide is composed of Alanine, Glycine and Serine and is written in shorthand as: Ala-Gly-Ser.