Final answer:
The reaction between two amino acids forming a dipeptide involves a condensation reaction where a peptide bond is formed between the amino group of one amino acid and the carboxyl group of another, resulting in the release of water and the linkage of the two amino acids.
Step-by-step explanation:
The reaction between two amino acids with side chains R₁ and R₂ involves the formation of a dipeptide. This occurs through a condensation reaction in which the amino group (-NH₂) of one amino acid reacts with the carboxyl group (-COOH) of another amino acid. During this process, the -OH from the carboxyl group and a hydrogen atom from the amino group are removed to form water, and a peptide bond, which is a covalent C-N bond, is established between the carboxyl carbon and the amine nitrogen.
The specific side chains (R₁ and R₂) do not participate in the formation of the peptide bond. However, these R groups define the unique characteristics of each amino acid. The peptide bond is critical for linking amino acids and, through repeated condensation reactions, can lead to the formation of polypeptides and eventually large proteins with specific functions.