For an example problem, let's take: "Draw the structure of the tripeptide Ser-Gly-Asp in its fully ionized form at pH 7.4." Solution: Explain how each amino acid's side chain is ionized. Serine's hydroxyl group is neutral. Glycine, being the smallest, has a hydrogen as its R group. Aspartic acid's carboxyl group is deprotonated (COO-) at neutral pH. Then, link them via peptide bonds between the amino and carboxyl groups. Emphasize the zwitterionic nature and the charges on nitrogen and oxygen atoms.