Which sequence correctly describes the formation of peptide bonds in proteins?

• A. Hydrolysis
• B. Oxidation
• C. Photolysis
• D. Dehydration

Answer: (D)

Peptide bonds form through dehydration synthesis, a condensation reaction. When two amino acids join, the carboxyl group of one and the amino group of the next release a water molecule, and a covalent bond—the peptide bond—forms between the carbon of the first amino acid and the nitrogen of the second. This is exactly how proteins are built during translation, as the ribosome links amino acids one by one via this dehydration step. Hydrolysis would instead break peptide bonds by adding water, while oxidation and photolysis involve other processes not responsible for forming the bond.