How are the cell walls of a plant and fungus different ?

Bacterial cell walls are different from the cell walls of plants and fungi which are made of cellulose and chitin, respectively. The cell wall of bacteria is also distinct from that of Archaea, which do not contain peptidoglycanwhere

The plant cell wall is made up of cellulose while the cell wall of fungus is made up of chitin. Cellulose is a polysaccharide made up of D-glucose which are joined by β 1-4 glycosidic linkage. They are the most abundant polysaccharide in the world.

Both plant and fungus cell walls are made up of polysaccharide of but chitin have modified glucose residue which contains amyl group instead of the OH group as in cellulose. So chitin is made up of N- acetyl-D-glucosamine residues which are also joined by β 1-4 glycosidic.  

Chitin is the second most abundant polysaccharide which makes exoskeleton of insects, crustaceans and cell wall of the fungus.