cellulose Flashcards
what is cellulose and where is it found?
- fibrous polysaccharide so it’s strong and structural
- found in the cell wall of plants
- provides rigidity and shape to the cell
what is the monomer of cellulose?
β glucose
what is the structure of β glucose?
see diagram in notes
what do β molecules do that α glucose molecules don’t?
β glucose molecules invert
what is the structure of cellulose and how is it formed?
- it’s a polysaccharide of β glucose molecules
- joined together by glycosidic bonds
- these bonds are formed in condensation reactions
- to form a long, straight chain
why is cellulose made up of a single type of polymer?
because only one type of glycosidic bond (β 1,4 glycosidic bond) is possible
what does the β 1,4 glycosidic bond cause?
every other β glucose monomer is inverted
how is the microfibril formed?
hydroxyl (OH) groups which project from either side of the β glucose chain form hydrogen bonds with the hydroxyl (OH) groups of other adjacent chains producing a three dimensional structure known as the microfibril
draw the structure of the microfibril
see diagram in notes
how are macrofibrils formed?
microfibrils are grouped into larger bundles known as macrofibrils
what is the structure of macrofibrils?
- macrofibrils in one layer are oriented in the same direction
- macrofibrils in successive layers are oriented in a different direction
- macrofibrils of these different layers are interwoven and embedded in a matrix providing rigidity
- the cellulose cell wall is usually fully permeable due to minute channels between the different layers of macrofibrils
what is the benefit of the matrix?
provides structure and rigidity
what is the benefit of the cellulose cell wall being fully permeable?
- water needs to move in and out of the plant cells
- water doesn’t enter the cells too much and cause cell lysis
