What type of bonds link amino acids in polypeptide chains?

The correct answer identifies the specific type of bonds that link amino acids in polypeptide chains as peptide bonds, also known as amide bonds. Peptide bonds form through a dehydration synthesis reaction, where the carboxyl group of one amino acid reacts with the amino group of another, releasing a water molecule and creating a covalent bond between the two amino acids. This bond is crucial for building proteins, as it defines the primary structure of a protein, linking amino acids in a specific order determined by the genetic code.

Although covalent bonds are indeed robust and encompass a variety of types, the term "covalent bonds" is broader and does not specifically highlight the unique formation occurring between amino acids. While ionic and hydrogen bonds play roles in the overall structure and stability of proteins, particularly in later levels of protein folding (secondary, tertiary, and quaternary structures), it is the peptide bonds that are responsible for the linear chain of amino acids that forms a polypeptide.