Cellulose is a polysaccharide found in plant cells. It is the main component of cell walls.
The monomer (smallest sugar component) of cellulose is $$\beta$$-glucose. Over 1000 monomers are assembled into long straight chains.
The glucose monomers are linked together by 1-4 glycosidic bonds (bonds between the first and the fourth carbon atom of the glucose molecule).
In order to form these bonds, alternate $$\beta$$-glucose monomers must rotate through 180 degrees. This rotation gives cellulose its characteristic straight chained structure.
Cellulose chains are arranged in parallel. These chains are held together by hydrogen bonds and are called microfibrils.