The peptide bond forms spontaneously via a condensation reaction that releases a small molecule like water. It has partial double bond character that restricts rotation, resulting in planar geometry. The phi and psi angles of the peptide backbone determine its conformation within allowed regions of the Ramachandran plot, avoiding steric clashes. While most peptide bonds adopt the trans configuration, proline favors cis. Protein function arises from its precise three-dimensional structure.