Cellulose is the main chemical that forms the main structure of plants. It is the most abundant macromolecule on Earth. It is also fiber. Cellulose is a very complex carbohydrate and consisting of 3,000 or more glucose units. Cellulose was discovered by Anselme Payen discovered in 1838. He isolated it from plant matter and determined its chemical formula. Cellulose is the most common organic compound on Earth.