What type of chemical bond links amino acids to form proteins?

• A. Hydrogen bonds
• B. Peptide bonds
• C. Ionic bonds
• D. Disulfide bonds

Answer: (B)

Amino acids are joined together by peptide bonds. A peptide bond forms when the amino group of one amino acid reacts with the carboxyl group of the next amino acid, releasing water in a dehydration synthesis reaction. Repeating this linkage builds a polypeptide chain that folds into a protein. The peptide bonds create the backbone of the protein and are the covalent links that hold the sequence of amino acids together.

Other bonds play roles in shaping and stabilizing the protein but do not form the main chain. Hydrogen bonds help stabilize secondary and tertiary structures, ionic bonds form between charged side chains, and disulfide bonds between cysteine residues stabilize folded forms.