What is a peptide bond?

A peptide bond is specifically a covalent bond that links two amino acids together in a protein. This bond forms through a condensation reaction, where the carboxyl group of one amino acid reacts with the amino group of another, releasing a molecule of water and creating a stable linkage. Peptide bonds are essential for building the primary structure of proteins and play a crucial role in determining the protein's overall shape and function.

The other descriptions do not accurately define a peptide bond. Ionic bonds typically occur between oppositely charged ions, while weak attractions, like hydrogen bonds or van der Waals forces, contribute to protein folding but are not peptide bonds. Lastly, lipid formation involves different types of bonds, such as ester bonds, rather than peptide bonds, which are strictly associated with amino acids and proteins.