A condensation reaction is where two small molecules react together to form a larger molecule with the elimination of a small molecule like water. Two amino acids can react in a condensation reaction to form a peptide bond and release water. This forms a dipeptide. Many condensation reactions can occur between amino acids to build up a peptide or protein chain.

Hydrolysis is the breaking of a bond by reacting with water. It can be catalysed with acid or alkali. Proteins and peptide chains can undergo hydrolysis to break the peptide bond and form its constituent amino acids.

Acid hydrolysis usually involves heating the protein under reflux with acid e.g. 6 moldm^-3 HCl(aq). This will use water to break the bond and form amino acids often with a positve charge due to the low pH depending on their isoelectric point.

Alkaline hydrolysis often involves heating just above 100°C with NaOH. This will form amino acid salts so on the carboxyl group will be COO^-Na⁺.