Cell wall There are several groups of organisms that have been called "fungi". Some of these groups (Oomycete and Myxogastria) have been transferred out of the Kingdom Fungi, in part because of fundamental biochemical differences in the composition of the cell wall. Most true fungi have a cell wall consisting largely of chitin and other polysaccharides. True fungi do not have cellulose in their cell walls. In fungi, the cell wall is the outer-most layer, external to the plasma membrane. The fungal cell wall is a matrix of three main components: Like plants, algae have cell walls. Algal cell walls contain either
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