Carbohydrates - Polysaccharides Flashcards
1
Q
How are polysaccharides formed
A
By the condensation of many glucose molecules
2
Q
How are glycogen and starch formed
A
Formed by the condensation of alpha glucose
3
Q
How is cellulose formed
A
Formed by the condensation of beta glucose
4
Q
Function of polysaccharides
A
- energy storage (plants - starch ; animals - glycogen)
- structural - cell wall
5
Q
Types of chains in polysaccharides
A
- branched or unbranched
- folded
- straight
6
Q
Why are starch and glycogen storage polysaccharides
A
- compact so large quantities can be stored
- insoluble so it’ll have no osmotic effect ; glucose would lower the water potential of a cell and it would cause water to move into the cells so then the cells would be a thicker cell wall and burst.
7
Q
Structure of glycogen
A
- Alpha glucose monomer
- 1,4 and 1,6 glycosidic bonds
- highly branched
- compact so can store more than amylopectin
8
Q
Structure of cellulose
A
- long unbranched chains of beta glucose
- joined by 1,4 glycosidic bonds
9
Q
Function of cellulose
A
- provides support to plant cell walls
- has high
-strengthened cell walls to provide support to the plant - tensile strength which allows it to be stretched without breaking which makes it possible for cell wall to withstand turgor pressure
10
Q
Structure and Role of starch
A
- starch is insoluble ; doesn’t affect water potential that way
- plants store energy as starch
- not all is used in respiration
- large molecule = store lots of glucose
- hydrolysed to form alpha glucose
- branched to get more glucose at the same time, easily accessible.
- amylose (10-30% of starch)
- helix shape allows it to be more compact and so its more resistant to digestion
11
Q
What is starch made up of (structure)
A
- amylose ( straight chain, no branches, forms a coil
- alpha glucose molecules
- molecules branched to form a 3D shape chains of thousands of glucose molecules
- 1,4 glycosidic bonds and 1,6 glycosidic bonds
- forms a coil
