(a) Hydroxyl groups only
(b) Uronic acids
(c) Nitrogen containing
Figure 1: Structures of the repeating units of some of the polysaccharides discussed in this review. Some of the structures are simplified (see text): branching is not shown for dextran, xylan, and pectin; the alginate structure shown shows the two linkage types rather than a formal repeating unit; the chitin and chitosan structures shown represent extremes of a continuum of structures.