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  • Created on: 28-01-13 13:20
Preview of Cellulose

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Only in plants/most abundant polysaccharide in nature. Made from beta glucose monomers by
condensation. Due to different shape of monomer the resulting polymer is a, ----, ---- chain.
Polymer containing beta 1, 4 glycosidic bonds.
Every other monomer needs to be flipped 180° in order to align OH at C1 with OH at C4 (bring them
into the same plane).
1 cellulose molecule = 10,000 monomers
Parallel cellulose molecules are stabilised by hydrogen bonds between OH groups.
Crosslinks between 60-70 cellulose molecules 1 microfibril.
100s of microfibrils are crosslinked by more H bonds to form 1 macrofibril.
Many macrofibrils are glued together by the polysaccharide pectin to form the cellulosefibres of the
cell wall (fibres crisscross in all directions.
Properties of cellulose
Strong, rigid fibres/high tensile strength/insoluble.
Cannot be broken down by animals as they do not have enzymes that can hydrolyse beta 1, 4
glycosidic bonds fibre (cellulose) provides "bulk".
Properties of cell wall
Very strong due to crisscross of fibres: prevents cells from bursting when water moves in and allows
water to diffuse along the appoplast pathway.
In turgid cells helps to support the whole plant = strength.
Gaps between fibres: fully permeable; gaps can be filled with other substances to male the wall fully
waterproof ie. lignin ----.
Arrangement of fibres determines how cells can grow or change their shape: ie. guard cells:
arrangement of fibres results in a shape change of the cell as water moves in that leads to opening of
the stomata.

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Energy storage molecule in liver and muscle cells (glycogen granules).
Similar structure as amylopectin BUT: more 1, 4 glucose chains and more 1, 6 branches more
compact than starch.
How do branched ends help digestion by enzymes?
More ends.…read more


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