polysaccharide

Question 1

Polysaccharide

Answer 1

• Large complex polymers, formed from a large number of monosaccharide units, which are their monomers
• These monomers are linked together by glycosidic bonds

Question 2

Starch / Glycogen as storage products

Answer 2

• these are polysaccharide
• used in plant/animal cells as storage products instead of glucose.
  - are insoluble and so have
  no osmotic effect
  - cannot diffuse out of the
  cell
  - compact molecules, can be
  stored in small places
  - carry a lot of energy in their
  C-H / C-C bonds

Question 3

Starch

Answer 3

• Main source of glucose for plants
• Made of a-glucose molecules bonded together in two ways forming two polymers, amylose and amylopectin

Question 4

Amylose

Answer 4

• linear
• unbranched
• 1-4 glycosidic bonds
• forms a chain which coils into a
  helix

Question 5

Amylopectin

Answer 5

• chains of glucose monomers
  joined with 1-4 glycosidic bond.
• cross-linked with a 1-6
  glycosidic bond
  - creates a side chain
  - normal 1-4 glycosidic
  bonds continue from the
  start of the branch

Question 6

Glycogen

Answer 6

• Main storage product in
  animals
• has 1-4 anf 1-6 glycosidic bonds
  - occurs more often than
  amylopectin
  - shorter side chains

Question 7

Cellulose structure

Answer 7

• individual cellulose molecules consists of long chains of B-glucose,
• these are joined by a 1-4 glycosidic bond to make a straight, unbranched chain.
• the B-glucose bond rotates adjacent glucose molecules
• hydrogen bonds form between the OH groups of adjacent parallel chains
  -these parallel cellulose molecules become tightly cross-linked by hydrogen bonds to form a microfibril
• these microfibrils are held in a bundle called a fibres.

call walls have several layers of fibres, which run parallel within a layer, but at an angle to the adjacent layer.

Question 8

Chitin

Answer 8

• polysaccharide found in the exoskeleton of insects and in fungal cell walls.
• has long chains of of B-1,4 bonds
• has groups derived from amino acids added, to form a heteropolysaccharide.
• strong, waterproof and light weight.
• adjacent monomers are flipped 180’
• the long parallel chains are cross-linked to each other by hydrogen bonds, forming microfibrils