What type of bond is formed between amino acids?

Amino acids are joined together through covalent bonds to form proteins. The specific type of covalent bond formed between the amino group of one amino acid and the carboxyl group of another is called a peptide bond. This strong bond results from a dehydration reaction, where a molecule of water is released as the two amino acids link together.

Covalent bonds are characterized by the sharing of electron pairs between atoms. In the case of peptide bonds, this sharing helps establish the primary structure of proteins, which is crucial for their functional and structural roles in biological systems. The stability and strength of covalent bonds make them essential for the integrity of protein structures.

In contrast, while hydrogen bonds can play a significant role in stabilizing the secondary and tertiary structures of proteins, they do not form the primary link between amino acids. Ionic bonds involve the attraction between charged groups but are not responsible for linking amino acids either. Metallic bonds, on the other hand, are not relevant in the context of organic molecules like amino acids. Thus, the correct answer emphasizes the fundamental importance of covalent bonding in protein formation.