Glucose are termed glucans. Glucose is produced by plants through the photosynthesis using sunlight, water and carbon dioxide and can be used by all living organisms as an energy and carbon source. However, most glucose does not occur in its free form, but in the form of its polymers, i.e. lactose, sucrose, starch and others which are energy reserve substances, and cellulose and chitin, which are components of the cell wall in plants or fungi and arthropods, respectively. These polymers are degraded to glucose during food intake by animals, fungi and bacteria using enzymes. All animals are also able to produce
Cellulose synthase (UDP-forming) Cellulose synthase (UDP-forming) In enzymology, a cellulose synthase (, "UDP-glucose:(1→4)-β--glucan 4-β--glucosyltransferase") is an enzyme that catalyzes the chemical reaction Thus, the two substrates of this enzyme are UDP-glucose and [(1→4)-β--glucosyl], whereas its two products are UDP and [(1→4)-β--glucosyl]. This enzyme is involved in the synthesis of cellulose. A similar enzyme utilizes GDP-glucose, cellulose synthase (GDP-forming) (EC 2.4.1.29). Cellulose is an aggregation of unbranched polymer chains made of β-(1→4)-linked glucose residues that makes up a large portion of primary and secondary cell walls. Although important for plants, it is also synthesized by most algae, some bacteria, and some animals. Worldwide, 2