ABSTRACT
Cellulose and hemicelluloses are macromolecules which are composed of carbohydrate monomers. Cellulose is built only from glucose; hemicelluloses are more complex and composed of several different sugar monomers. In cellulose the building blocks are connected in the growing cell wall by stepwise enzymatic processes, with four reactions necessary to add one sugar unit to the growing polymer chain:
1 Activation of glucose to glucose-6-phosphate. 2 Isomerization of glucose-6-phosphate to glucose-1-phosphate. 3 Pyrophosphorylation with GTP to GDP-glucose. 4 Addition of the activated glucose molecule to the growing cellulose chain.
