What type of bond forms between amino acids in proteins?

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

Answer: (C)

A peptide bond is a specific type of covalent bond that forms between amino acids during protein synthesis. This bond is created through a dehydration synthesis reaction or condensation reaction, where the amino group (NH2) of one amino acid reacts with the carboxyl group (COOH) of another, releasing a molecule of water (H2O) in the process. The resulting bond links the two amino acids into a dipeptide, and as additional amino acids are added, they form a polypeptide chain, which eventually folds into a functional protein.

Understanding that peptide bonds connect amino acids is crucial because these bonds define the primary structure of proteins. While covalent bonds broadly encompass a range of types, including peptide bonds, not all covalent bonds are specifically peptide bonds. The distinction is important because it situates peptide bonds within the specific context of protein structure.

Ionic bonds involve the electrostatic attraction between oppositely charged ions, which is not what connects amino acids in proteins. Hydrogen bonds often contribute to the secondary and tertiary structures of proteins by stabilizing folded regions but do not link amino acids directly. Thus, recognizing the uniqueness of peptide bonds is fundamental to comprehending protein assembly and overall cellular function.