Question
Illustrate a glycosidic, peptide and a phosphodiester bond.
Solution
(1) Glycosidic - Monosaccharides in a polysaccharide chain are linked by a glycosidic bond. The bond is formed between two carbon atoms of two adjacent monosaccharides with loss of a water molecule.
(2) Peptide bond: Amino acids in a polypeptide or protein are linked by a peptide bond, which is formed when the carboxyl group ie. COOH of one amino acid reacts with the amino (–NH2) group of the next amino acid with the elimination of a water molecule . 
(3) Phosphodiester bond : In a nucleic acid the phosphate group and sugar are joined together by phosphodiester bonds. An bonds is formed between phosphate and pentose sugar molecule in a nucleotide. The bond is called phosphodiester bond because there is an ester bond on either side. 
