A peptide bond is a type of chemical bond that links amino acids together to form proteins. It occurs when the carboxyl group of one amino acid reacts with the amino group of another, releasing a molecule of water in a process called dehydration synthesis. This bond is crucial for building the primary structure of proteins, which are essential for various biological functions. Peptide bonds are strong and stable, allowing proteins to maintain their structure under different conditions. The sequence of amino acids connected by peptide bonds determines the protein's unique properties and functions, influencing everything from enzyme activity to hormone regulation in living organisms.