Cellulose is the basic structural component of plant cell walls and is also found in vegetable matter, cotton and wood. While indigestible by humans, it is still an important source of fiber. High amounts of cellulose are consumed by herbivores, usually with the assistance of bacteria.
Plant cell walls appear as little boxes that are given their shape by two chemicals: cellulose and lignin. The cellulose is tough and flexible with the lignin acting as a sort of "glue" holding the cellulose together. Because of the nature of the cellulose and lignin "team," plants can grow into tall trees, flexible grass or anything in between. Cellulose and its derivatives are found in many manufactured products, from paper to plastics and even money itself.