Polysaccharides Flashcards
What is a polysaccharide?
Macromolecules that are polymers formed by many monosaccharides joined together by a glycosidic bonds in a condensation reaction to form chains.
How is starch and glycogen suited as a storage molecule?
They are compact and insoluble (no osmotic effect)
What is starch?
Storage polysaccharide of plants
What is the structure of amylose?
Unbranded helix shaped chain with 1,4 glycosidic bonds between alpha glucose molecules
How does the helix shake of amylose help?
Enables it to be more compact and thus more resistant to digestion
What does amylopectin consist of ?
1,4 glycosidic bonds between alpha glucose molecules & 1,6 glycosidic bonds form between glucose molecules, creating a branched molecule.
What do the branches of amylopectin result in?
Many terminal glucose molecules that can be easily hydrolysed for use during cellular respiration or added to for storage
What is glycogen?
A storage polysaccharide of animals and fungi, it’s highly branched and not coiled.
What cells have a high concentration of glycogen, and why?
Liver and Muscle cells, as cellular respiration rates are higher due to animals being mobile.
Is glycogen less or more branched and compact than amylopectin?
More branched & compact
Benefits of glycogen being highly branched?
Branching enables more free ends where glucose molecules can either be added or removed allowing for condensation & hydrolysis reactions to occur more rapidly. - storage/ real ease of glucose can suit demands of the cell
What is celluloses structure?
A polymer consisting of long chains of beta glucose joined together by 1,4 glycosidic bonds
As beta glucose is an isomer of alpha glucose to form the 1,4 glycosidic bonds, wha must occur in cellulose?
Each consecutive beta-glucose molecules must be rotated 180 degrees to each other.
Due to the inversion of b-glucose molecules, what bonds form between the long chains giving cellulose its strength?
Hydrogen bonds
Due to the inversion of b-glucose molecules, what bonds form between the long chains giving cellulose its strength?
Hydrogen bonds
Where is cellulose the main structural component of and why?
Cell walls, due to its strength which is a result of the many hydrogen bonds between the parallel chains of microfibrils.
What does the high tensile strength of cellulose allow it to do?
Allows it to be stretched without breaking, making it possible for cell walls to withstand turgor pressure
What does the high tensile strength of cellulose allow it to do?
Allows it to be stretched without breaking, making it possible for cell walls to withstand turgor pressure
What do the cellulose fibres being freely permeable allow?
Allows water and solutes to leave or reach the cell surface membrane
What monomer is present in cellulose and starch
Alpha glucose
What is an isomer
Organic molecules that have the same chemical structure but different structural formula
Explain how cellulose gives cotton its strength
The many hydrogen bonds found between the parallel chains of microfibrils.
Cellulose fibres and other molecules (lignin) found in the cell wall form a matrix
Explain how cellulose gives cotton its strength
The many hydrogen bonds found between the parallel chains of microfibrils.
Cellulose fibres and other molecules (lignin) found in the cell wall form a matrix
List 2 similarities and 2 differences between the structures of starch and glycogen
Both are branched molecules, both contain 1,4 and 1,6 glycosidic bonds.
Starch is made up of amylose and amylopectin polysaccharides.
GLycogen is more highly branched than starch.
Glycogen has more terminal ends than starch.
Explain one reason why pea cells use starch as a storage molecule rather than glucose
Starch is insoluble so does not affect water potential.
-starch has a coiled/helical structure so can fit many molecules into a small area.
Describe how a student could separate a mixture os monosaccharides in solution.
- paper chromatography
-a spot of solution is placed on chromatography paper and the paper is suspended in a solvent.
-larger molecules will move slower on the paper - the original mixture to separate out into different spots/ bands.
