Cellulose, a polysaccharide, is an organic molecule which is found in plants. Most of the cells have cellulose in their cell walls which functions as the support in the structure of the cell. Cellulose is made up of glucose units arranged in linear chains. It has a general formula of `(C6H10O5)n` and about 33% percent of the total plant matter is cellulose which made it one of the most abundant organic compounds on earth. It is being used industrially and converted to other resources such as paper, textile, plastics and other industrial materials.
The major component in the rigid cell walls in plants is cellulose. Cellulose is a linear polysaccharide polymer with many ß-glucose (having C1-OH upwardly directed) monosaccharide units. The acetal linkage is beta which makes it different from starch. This peculiar difference in acetal linkages results in a major difference in digestibility in humans. Starch is also a polymeric carbohydrate consisting of a large number of α-glucose (having C1-OH downwardly directed) units. Assembly of a large number of α-glucose units make it coil-like in shape. Starch is produced by all green plants as an energy store. Glycogen is the storage form of glucose in animals and humans which is analogous to the starch in plants. Glycogen is another polysachcharide synthesized and stored mainly in the liver and the muscles. Structurally, glycogen can be called the truncated analogue of starch. Glucose is not a polysachcharide, rather a monomer of most of them.
So, a polysachcharide which is the primary component of plant cells, is cellulose.