The bond by which amino acids join together to form a protein is called a peptide bond.
1. Dipeptide bond: The peptide bond that connects two amino acids is called a dipeptide bond.
2. Tripeptide bond: The peptide bond that connects three amino acids is called tripeptide bond.
3. Oligopeptide bond: The peptide bond that connects few (4-10) amino acids is called oligopeptide bond.
4. Polypeptide bond: The peptide bond that connects many (50) amino acids is called polypeptide bond.