Glycogen
Glycogen is used for the storage of glucose, and is more efficient than amylopectin. It is highly branched and compact – therefore it is considered energy dense.
It is composed of alpha-glucose molecules joined by alpha 1, 4 glycosidic bonds with alpha 1, 6 branches that are found every 20 to 30 monomers.
Glycogen is also insoluble, therefore it does not affect the osmotic balance of the cell. Also, it is a large molecule and cannot leave the cell.
Cellulose
Cellulose is the main component in cell walls – therefore it is very strong as thousands of chains link together. This provides the plant with structure and stability.
It is an unbranched chain composed of beta-glucose molecules joined by beta 1, 4 glycosidic bonds and the alternate glucose molecules are inverted. The hydrogen bonds between the chains produce microfibrils.
This carbohydrate is also fully permeable – meaning that water and numerous other substances can move through it e.g. water through a plant’s membrane.
The enzyme which breaks cellulose down is cellulase.