Slides in this set
· Plants store sugars for later use in the form of storage
polysaccharides Starch in seeds & storage organs (potato
· An important component of food & a major energy source
· Made up of chains of -glucose monomers linked by glycosidic
bonds that are formed by condensation reactions.
· The unbranched chain is wound into a coil (helix) making it
· Stains deep blue with iodine solution.…read more
The main role of starch is energy storage, something it is specially
suited for because:
· being insoluble, it does not tend to draw H2O into cells by
· it also does not easily diffuse out of the cells.
· being compact, a lot of it can be stored in a small space.
· when hydrolyzed it forms -glucose, which is both easily
transported & readily used in respiration.
· Starch is never found in animal cells. Instead a similar
polysaccharide, called glycogen, serves the same role.…read more
· Very similar in structure to starch but has shorter chains and is
more highly branched.
· Major storage polysaccharide in animal cells Animal starch
· Stored as small granules mainly in muscles and liver.
· More readily hydrolyzed to -glucose (because of smaller chains).
· Glycogen is found in animal cells but never in plant cells.…read more
· Made of monomers of -glucose rather than -glucose.
· In the -glucose units, the positions of the H group and the OH
group on a single carbon atom are reversed.
· The OH group is above, rather than below, in -glucose.
· This means that to form a glycosidic links, each -glucose
molecules must be rotated by 1800.
· The result is that the CH2OH group on each alternates between
being above and below the chain.…read more