1.4 — carbohydrate: polysaccharide Flashcards

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1
Q

what are 4 examples of polysaccharides?

A

starch (unbranched), starch (branched), glycogen, cellulose

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2
Q

how is starch used?

A

by plants to store excess glucose — being hydrolysed back into glucose when plants require energy

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3
Q

what is starch made up of?

A

many alpha glucose monomers joined by both 1,4 and 1,6 glycosidic bonds to form chains

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4
Q

what are the two forms of starch chain?

A

unbranched and branched

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5
Q

what features of starch allow it to work well as a store of energy? (5)

A
  1. insoluble — does not affect water potential of the cell, so water is not drawn to it by osmosis
  2. large — cannot diffuse out of cells
  3. many side branches — allows enzymes to hydrolyse the glycosidic bonds easily to rapidly release glucose
  4. coiled — makes it compact do that a lot of glucose can be stored in a small space
  5. hydrolysis releases alpha glucose monomers — these are readily used in respiration
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6
Q

what is glycogen used for and by whom?

A

glycogen is used by animals to store excess glucose

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7
Q

what is glycogen made up of?

A

glycogen is made up of many alpha glucose monomers which are joined via both 1,4 and 1,6 glycosidic bonds

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8
Q

what features of glycogen allow it to work well as a store of energy? (5)

A
  1. insoluble — it does not affect the water potential of cells, and therefore does not cause water to enter cells via osmosis
  2. compact — a lot of glucose can be stored in a small place
  3. more highly branched than starch — enzymes can easily hydrolyse the glycosidic bonds to rapidly release glucose
  4. large — cannot diffuse out of cells
  5. releases alpha glucose molecules — (via hydrolysis) they can be used in respiration
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9
Q

what is cellulose made from?

A

cellulose is a polysaccharide formed from beta glucose.

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10
Q

what is cellulose’s primary use?

A

to provide structural support for plant cell walls

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11
Q

what must beta glucose monomers do to be able to bond to each other and why?

A

one monomer must invert 180˚(flip upside down) as when unflipped beta glucose line up next to each other, the hydroxyl groups (OH) on carbons 1 and 4 are too far to form a 1,4 glycosidic bonds. by one beta glucose being flipped, the hydroxyl groups are close enough to react

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12
Q

what type of chains do beta glucose monomers form? (3)

A

long, straight, unbranched chains

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13
Q

what does the alternating inversion of the beta glucose molecules allow?

A

it hydrogen bonds to form between individual chains, which in huge numbers provides strength to cellulose.

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14
Q

what do multiple cellulose chains linked via hydrogen bonds form (2)?

A

bundles called microfibrils which join together to make macrofibrils, which then combine to make strong cellulose fibres in the plant cell wall.

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15
Q

how has cellulose adapted to its role? (3)

A
  1. long, straight and unbranched chains — provide rigidity to the cell wall
  2. hydrogen bonds — these cross link the chains to add collective tensile strength
  3. microfibrils - these provide additional strength
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16
Q

where is cellulose found?

A

in plants (cell wall)

17
Q

where is unbranched starch found?

A

plants

18
Q

where is branched starch found?

A

plants

19
Q

where is glycogen found?

A

animals

20
Q

what monomer is cellulose made from?

A

beta glucose

21
Q

what monomer is unbranched starch made from?

A

alpha glucose

22
Q

what monomer is branched starch made from?

A

alpha glucose

23
Q

what monomer is glycogen made from?

A

alpha glucose

24
Q

what type of bonds does cellulose contain?

A

1,4 glycosidic bonds

25
Q

what type of bonds does unbranched starch contain?

A

1,4 and 1,6 glycosidic bonds

26
Q

what type of bonds does branched starch contain?

A

1,4 and 1,6 glycosidic bonds

27
Q

what type of bonds does glycogen contain?

A

1,4 and 1,6 glycosidic bonds

28
Q

what shape are the chains in cellulose?

A

straight chains

29
Q

what shape are the chains in unbranched starch

A

coils/helical

30
Q

what shape are the chains in branched starch

A

moderately branched

31
Q

what shape are the chains in glycogen?

A

very branched