Polysaccharides Flashcards
When is a polysaccharide formed?
More than two monosaccharides are joined together by condensation reactions
How are lots of alpha glucose molecules joined together?
By glycosidic bonds to form amylose
What’s the main energy storage material in plants?
Starch
Cells get energy from…
Glucose
Plants store excess glucose as…
Starch
When a plany needs more glucose…
It breaks down starch to release the glucose
Starch is a mixture of…
Two polysaccharides of alpha-glucose- amylose and amyloceptin
Amylose:
Long, unbranched chains of alpha-glucose
Angles of glycosidic bonds give it a coiled structure
Coiled structure makes it compact- good for storage
Amyloceptin:
Long, branched chains of alpha-glucose
Side branches allow enzymes that break down the molecule to get at the glycosidic bonds quickly
Glucose can be released quickly
Starch is…
Insoluble in water
What doesn’t starch affect?
Water potential- doesn’t cause water to enter cells by osmosis
Otherwise they would swell
Makes them good for storage
Iodine test for starch:
Add iodine dissolved in potassium iodine solution to the test sample
If starch is present, sample changes from browny-orange to dark, blue-black colour
What should you always talk about with the iodine test for starch?
Iodine in potassium iodine solution, not just iodine
What is the iodine test used for?
Experiment is used on digestion of starch
What’s the main energy storage material in animals?
Glycogen
Animals get energy from…
Glucose
Animals store excess glucose as…
Glycogen
Glyocogen is a…
Polysaccharide of alpha-glucose
Glyocogen’s structure:
Similar to amyloceptin, except has more side branches coming off it
What does glycogen having a lot of branches mean?
Stored glucose can be released quickly- important for energy release in animals
What kind of molecule is glycogen?
Very compact- good for storage
What’s the major component of cell walls in plants?
Cellulose
Cellulose is made of…
Long, unbranched chains of beta-glucose- polysaccharide of beta-glucose
What happens when beta molecules bond?
Form straight cellulose chains
