During a dehydration reaction, a peptide bond is formed between amino acids.

Here's how it works:

* Dehydration: A water molecule (H₂O) is removed from the reacting molecules.

* Peptide bond: The carbon atom of the carboxyl group (COOH) of one amino acid joins with the nitrogen atom of the amino group (NH₂) of another amino acid.

* Formation of a dipeptide: This process creates a dipeptide, which is a molecule consisting of two amino acids linked by a peptide bond.

This process can continue, adding more amino acids to the chain, eventually forming a polypeptide (a long chain of amino acids).