Starch is the nourishing part in a lot of our staple foods (potatos, cereals etc.) and easily digestible. Cellulose is a major component of wood (and cotton and paper) and of what we call “fiber” in our food, the stuff we cannot digest.

Both starch and cellulose are long, sometimes interlinked chains of glucose molecules. The only difference is at which corner of each glucose molecule the next is attached.