What type of bond forms between amino acids in a protein?

• A. Ionic bond
• B. Covalent bond
• C. Hydrogen bond
• D. Peptide bond

Answer: (D)

The bond that forms between amino acids in a protein is known as a peptide bond. This specific type of covalent bond occurs during the process of protein synthesis, where the carboxyl group (-COOH) of one amino acid reacts with the amino group (-NH2) of another, releasing a molecule of water (H2O) in a condensation reaction. The resulting bond links the two amino acids together into a dipeptide, and this process can repeat to form longer chains of amino acids, ultimately leading to a fully formed protein.

While other types of bonds, such as ionic and hydrogen bonds, can play significant roles in the overall structure and stability of the protein after it has been formed (for example, the tertiary and quaternary structures), the peptide bond is the primary linkage that directly connects the amino acids in the sequence of the protein. Thus, understanding the formation of peptide bonds is crucial to grasping how proteins are built and how their structure is determined.