Starch, glycogen and cellulose Flashcards
what is starch
polysaccharide found in many parts of plants
where is starch mainly found?
in many parts of a plant in the form of small grains
what is starch made up of?
chains of alpha glucose monosaccharides linked by glycoside bonds that are formed by condensation reactions
how is the molecule very compact?
the unbranched chain is wound into a tight coil
what is the difference between the structure of glycogen and starch?
glycogen has shorter chains and is more highly branched
what is the major carbohydrate storage product of animals?
glycogen
where is glycogen mainly stored in animals?
muscles and liver
why are starch and glycogen suited for their main roles?
- insoluble, doesn’t affect osmosis
- large- can’t get lost in cell membrane
- compact- lots of energy in small space
- easily hydrolysed
why is glycogen even more readily hydrolysed than starch?
it is made up of smaller chains
where is glycogen never found?
in plant cells
what monomers is starch and glycogen made up of?
alpha glucose
starch- mainly 1, 4
glycogen- more 1,6
what monomers is cellulose made up of?
beta glucose
what happens to beta glucose when it undergoes condensation reaction?
one turns over, C6 points out alternately
what is the structure of cellulose chains?
strain, unbranched chains
what bonds are between adjacent chains?
hydrogen bonds
what does the sheer overall number of hydrogen bonds do to the cellulose?
they make a considerable contribution to strengthening cellulose, making it a viable structural material.
what are the cellulose molecules grouped together to form?
microfibrils, which are arranged in parallel groups called fibres
what is cellulose a major component of?
plant cell walls and provide rigidity to the plant cell
how does the cellulose cell wall stop cells from bursting as water enters by osmosis?
it exerts an inward pressure that stops that stops any further influx of water.
as a result living plant cells are turgid and push against one another
why are cellulose good for their function?
- Very strong structure with strands for tension
- Lots of cells- rigidity
- Hold leaves horizontal- absorb more sunlight
