BM : Polysaccharides Flashcards
(21 cards)
3 examples of polysaccharides?
- starch
- glycogen
- cellulose
Starch is energy stored in?
Plants
Glycogen is energy stored in?
Animals
Cellulose makes up what?
The cell wall in plants
Starch is a long chain of what?
Alpha glucose
Glycogen is a long chain of
Alpha glucose
Cellulose is a long chain of
Beta glucose
Are polysaccharides carbohydrates?
Yes
What are polysaccharides made up of?
A long chain of monosaccharides joined by condensation reactions/ glycosidic bonds
What is starch made from?
Hint : both begin with A
- amylose
- amylopectin
What is amylose
A long straight chain of alpha glucose which is coiled
What is amylopectin
Straight chain of alpha glucose with side branches (1,6 glycosidic bond)
Structure of Glycogen
Straight chain of alpha glucose with side branches
3 properties of starch and glycogen
- Insoluble
- Coiled/ branched
- Branched/ chained
Insoluble?
Do not affect water potential of cell, do not diffuse out of cell
Coiled/ branched?
Compact, more can fit into cell
Branched/ chained
glucose removed from the end
Structure of cellulose
- Beta glucose arranged in a straight chain (each alternative B-glucose is rotated 180 degrees)
- many cellulose chains are cross linked by hydrogen bonds to form microfibrils
- many microfibrils are cross linked to form structure of cell wall
- strong material
Test of starch?
Iodine, turns blue/ black
test for reducing sugars
heat with benedicts, turns brick red
Test for non-reducing sugars
- Heat with benedicts, no changed
- therefore add dilute hydrochloric acid (hydrolyses glycosidic bond)
- then add sodium hydrogencarbonate (neutralises solution)
- heat with benedicts, turns brick red
