polysaccharides

Question 1

what is meant by a polysaccharide ?

Answer 1

made of many monosaccharides and are formed by a condensatoin reaction between many glucose monomers

Question 2

what are the 3 examples of polysaccharides ?

Answer 2

starch
cellulose
glycogen

Question 3

what is starch ?

Answer 3

it is a store of glucose that is found in plants

Question 4

what is cellulose ?

Answer 4

provides structural strength in plants

Question 5

what is glycogen ?

Answer 5

a store of glucose that is found in animals

Question 6

how is starch formed ?

Answer 6

starch is formed by the condensation of 2 polymers of alpha glucose

Question 7

what are the 2 polymers of alpha glucose that create starch ?

Answer 7

• amylose
• amylopectin

Question 8

where is starch found ?

Answer 8

starch is found inside starch grains found in chloroplasts in a plant cell

Question 9

what is the function of starch ?

Answer 9

it is an insoluble store of glucose

Question 10

what are the features of the structure of amylose ?

Answer 10

• forms a 1-4 glycosidic bond
• has a helical structure which makes it compact
• has unbranched (straight) chains

Question 11

what are the features of the structure of starch’s polymer : amylopectin ?

Answer 11

• 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

Question 12

how is glycogen formed ?

Answer 12

glycogen is formed by the condensation reaction of alpha glucose

Question 13

where is glycogen found ?

Answer 13

• muscle cells
• liver cells
  in animals

Question 14

what is the function of glycogen ?

Answer 14

• it is an insoluble store of glucose

Question 15

wat are the structural features of glycogen ?

Answer 15

• 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

Question 16

how is cellulose formed ?

Answer 16

• cellulose is formed by the condensation of beta glucose

Question 17

where is cellulose found ?

Answer 17

• it is found in the cell walls of plants

Question 18

what is the function of cellulose ?

Answer 18

provides structural and mechanical support to the cell wall

Question 19

describe the structure of cellulose ?

Answer 19

• 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

Question 20

what do layers of cellulose chains create ?

Answer 20

a microfibril

Question 21

how do hydrogen bonds provide structural strength to cellulose ?

Answer 21

hydrogen bonds are weak by themselves
but due to the large number of them in the cellulose structure, they collectively provide strength

Question 22

How does the structure of starch lead to its function ?

Answer 22

• 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

Question 23

how does the structure of cellulose lead to its function ?

Answer 23

• many hydrogen bonds provide collective strength
• insoluble so won’t affect water potential

Question 24

how does the structure of glycogen lead to its function ?

Answer 24

• branched structure increases surface area for rapid hydrolysis back to glucose
• insoluble so won’t affect water potential