Polysaccharides, which form the structural elements in the cell walls of bacteria and plants, are polymers of monosaccharide units. When the number of monosaccharides is small, they are termed oligosaccharides. Examples are:

• Starch consists of Amylose (a-Glc(1-->4)a-Glc)_n) and amylopectin (mixture of a-Glc(1-->4)a-Glc)_n and a-Glc(1-->6)a-Glc)_n subunits).
• Glucogen has the same subunits as amylopectin but with different ratio.
• Cellulose (b-Glc(1-->4)a-Glc)_n
• Quitine contains b-linkage N-acetil-D-glucosamine subunits