Illustrate a glycosidic, peptide and a phospho-diester bond.

(b) Peptide bond is a covalent bond that is formed between two adjacent amino acids by condensation of NH${}_2$ gp of one amino acid and C=O group of other amino acid and hence, it can be depicted as

(c) Phosphodiester bond is a strong covalent bond formed between phosphate and two adjacent sugar groups. Such bonds form the sugar-phosphate backbone of nucleic acids.