Ontario Grade 12 University Biology (SBI4U) Course Practice Exam

The bond that is formed between amino acids in a polypeptide chain is called a peptide bond. This type of bond is specifically a covalent bond, formed through a dehydration synthesis reaction where the carboxyl group of one amino acid reacts with the amino group of another, releasing a molecule of water. The resulting bond links the two amino acids together, forming a dipeptide. As more amino acids are added in this manner, a long chain of amino acids, or polypeptide, is created, which eventually folds into functional proteins.

While hydrogen bonds, ionic bonds, and covalent bonds play important roles in protein structure and function, they are not the specific type of bond that links amino acids in a polypeptide chain. For instance, hydrogen bonds are crucial for stabilizing the secondary and tertiary structures of proteins, and ionic bonds can occur between charged side chains of the amino acids, contributing to the overall stability and shape of the protein, but the primary bond linking the amino acids themselves is indeed the peptide bond.