polysaccharides Flashcards
what is meant by a polysaccharide ?
made of many monosaccharides and are formed by a condensatoin reaction between many glucose monomers
what are the 3 examples of polysaccharides ?
starch
cellulose
glycogen
what is starch ?
it is a store of glucose that is found in plants
what is cellulose ?
provides structural strength in plants
what is glycogen ?
a store of glucose that is found in animals
how is starch formed ?
starch is formed by the condensation of 2 polymers of alpha glucose
what are the 2 polymers of alpha glucose that create starch ?
- amylose
- amylopectin
where is starch found ?
starch is found inside starch grains found in chloroplasts in a plant cell
what is the function of starch ?
it is an insoluble store of glucose
what are the features of the structure of amylose ?
- forms a 1-4 glycosidic bond
- has a helical structure which makes it compact
- has unbranched (straight) chains
what are the features of the structure of starch’s polymer : amylopectin ?
- forms 1-4 and 1-6 glycosidic bonds (1-6 causes it to be branched)
- has highly branched chains
- it is large so it cannot pass through the cell membrane
how is glycogen formed ?
glycogen is formed by the condensation reaction of alpha glucose
where is glycogen found ?
- muscle cells
- liver cells
in animals
what is the function of glycogen ?
- it is an insoluble store of glucose
wat are the structural features of glycogen ?
- many 1-6 glycosidic bonds to create a highly branched polymer
- contains also 1-4 gycosidic bonds
( stress importance of it being more branched than amylopectin ) - it can be compacted easily
how is cellulose formed ?
- cellulose is formed by the condensation of beta glucose
where is cellulose found ?
- it is found in the cell walls of plants
what is the function of cellulose ?
provides structural and mechanical support to the cell wall
describe the structure of cellulose ?
- only contains 1-4 glycosidic bonds
- creates long, straight chains of beta glucose
- straight chains are held together by many hydrogen bonds
- to form a fibril structure
what do layers of cellulose chains create ?
a microfibril
how do hydrogen bonds provide structural strength to cellulose ?
hydrogen bonds are weak by themselves
but due to the large number of them in the cellulose structure, they collectively provide strength
How does the structure of starch lead to its function ?
- helix can compact to fit a lot of glucose in a small space
- branched structure increases surface area for rapid hydrolysis back to glucose
- insoluble so it won’t affect water potential
how does the structure of cellulose lead to its function ?
- many hydrogen bonds provide collective strength
- insoluble so won’t affect water potential
how does the structure of glycogen lead to its function ?
- branched structure increases surface area for rapid hydrolysis back to glucose
- insoluble so won’t affect water potential
