Cellulose

Cellulose is a substance found in the cell walls of plants. Although cellulose is not a component of the human body, it is nevertheless the most abundant organic macromolecule on Earth. The chemical structure of cellulose resembles that of starch, but unlike starch, cellulose is extremely rigid (Figure 1). This rigidity imparts great strength to the plant body and protection to the interiors of plant cells.

Figure 1. The structure of cellulose. Illustration by Hans & Cassidy. Courtesy of Gale Group.