First 256 words of the document:
A polysaccharide made up of BETA GLUCOSE MOLECULES.
A CONDENSATION REACTION between the OH group on the first carbon of one glucose and the OH on the fourth carbon of an adjacent glucose
molecule links the 2 molecules. A 1, 4 glycosidic bond forms.
There are none of the 1, 6 bonds that occur in Starch which are made up of alpha glucose molecule. Therefore, cellulose is a long, unbranched molecule.
Unlike an amylase molecule which winds into a spiral, the cellulose molecules remain as straight chains.
Hydrogen bonds form between the OH groups in neighbouring cellulose chains, forming bundles called MICROFIBRILS.
Individually, the hydrogen bonds are weak compared with glycosidic bonds however the large amount of hydrogen bonds together produce a strong
The arrangement of cellulose microfibrils in plant cell walls
The microfibrils are wound in a helical arrangement around the cell and stuck together with polysaccharide glue (hemicelluloses and pectins) Pectins act
as cement and hold the cells together.
The arrangement of the cellulose microfibrils within a matrix of hemicelluloses and pectins makes the wall very strong.
The microfibrils are laid down at different angles (forming a net-like structure), which make the wall strong and flexible.
The SECONDARY THICKENING of cell walls also makes them strong.
When some structural plant cells have finished growing, they produce a secondary cell wall between the normal cell wall and the cell membrane. This new
wall is usually thicker and contains more lignin.