Biological Molecules : polysaccharides

Question 1

polysaccharides are…

Answer 1

…polymers of many glucose molecules linked by condensation reactions

Question 2

glycogen is…

Answer 2

…the storage polysaccharide of animals

Question 3

starch is…

Answer 3

…the storage polysaccharide of plants

Question 4

cellulose is…

Answer 4

…the structural polysaccharide of plant cell walls

Question 5

chitin is…

Answer 5

…another structural polysaccharide of fungal cell walls and exoskeletons

Question 6

linear polysaccharides have…

Answer 6

…1,4 glycosidic links

Question 7

branched polysaccharides have…

Answer 7

…1,4 glycosdic links and 1,6 glycosidic links between the branches

Question 8

polysaccharides are ideal for storage because…

Answer 8

• glucose is easily added/removed by condensation and hydrolysis
• insoluble so remain inside cells without affecting their osmotic potential
• compact

Question 9

the two types of starch are:

Answer 9

amylose and amylopectin

Question 10

the function of starch is:

Answer 10

store lots of energy and release glucose quickly

Question 11

amylose structure:

Answer 11

• alpha glucose monomers
• coiled chains of 1,4 glycosidic bonds

Question 12

amylopectin structure:

Answer 12

• alpha glucose monomers
• 1,4 and 1,6 glycosidic links
• branches between carbons 1 and 6 of adjacent monomers

Question 13

glycogen structure:

Answer 13

• alpha glucose monomers
• coiled and branched with 1,4 and 1,6 glycosidic links

Question 14

glycogen function:

Answer 14

stores lots of energy and enzymes can quickly release glucose for respiration

Question 15

cellulose structure:

Answer 15

• monomers of beta glucose
• parallel chains of 1,4 glycosidic bonds
• every other glucose rotated 180 degrees
• hydrogen crosslinks between OH groups forming microfibrils

Question 16

cellulose function:

Answer 16

very strong so it supports cell wall and prevents it bursting when turgid

Question 17

chitin structure:

Answer 17

• monomers of beta glucose
• parallel chains of 1,4 (beta) glycosidic bonds
• every other glucose rotated 180 degrees
• hydrogen crosslinks between OH groups forming microfibrils
• acetyl amide side groups replacing the OH group of carbon 2

Question 18

chitin function:

Answer 18

• exoskeletons of insects, spiders and crustaceans
• fungal cell walls
• leathery when pure
• hardens due to calcium carbonate deposition
• strong, waterproof and lightweight