Deduce a balanced equation for a condensation reaction that produces the tripeptide Ser-Lys-Phe. Label the peptide linkages, $\mathrm{N}$-terminal, and $\mathrm{C}$-terminal in the resulting peptide.

The tertiary structure of protein describe the overall folding of the chains to give the protein its three-dimensional shape.This is caused by interactions between the side-chains of amino acid residues. Consider the two segments of a polypeptide chain shown in figure.

Deduce the type of interaction that can occur between the side-chains of Trp and Ile, Cys and Cys, and Tyr and His.