Carbohydrate polysaccharides

Question 1

what polysaccharides am I expected to know?

Answer 1

starch, glycogen, cellulose

Question 2

is starch plant or animal based?

Answer 2

plant based energy storage molecule

Question 3

what is starch made up of?

Answer 3

two types of α glucose polymers: amylose and amylopectin

Question 4

what glycosidic bonds does amylose have?

Answer 4

α 1,4

Question 5

is amylose branched or unbranched?

Answer 5

unbranched

Question 6

what shape is amylose?

Answer 6

helix shape

Question 7

what is the effect of amylose’s shape?

Answer 7

the helix shape enables it to be more compact and thus it is more resistant to digestion

Question 8

what bonds does amylopectin have?

Answer 8

α 1,4 and 1,6

Question 9

is amylopectin branched or unbranched?

Answer 9

branched

Question 10

what are 4 properties of starch?

Answer 10

-insoluble
-compact granule
-branching
-large molecule

Question 11

what is the effect of starch’s insolubility on its function?

Answer 11

no effect on water potential

Question 12

what is the effect of starch’s compactness?

Answer 12

takes up little space

Question 13

what is the effect of starch’s branching?

Answer 13

there are multiple sites for rapid hydrolysis

Question 14

what is the effect of starch’s size?

Answer 14

it is a large molecule therefore there are many glucose molecules for respiration

Question 15

what is the storage polysaccharide in plants?

Answer 15

starch

Question 16

which constituent molecules of starch is hydrolysed faster?

Answer 16

amylopectin (has more branches tf more terminal glucose molecules free to hydrolyse)

Question 17

how is starch stored?

Answer 17

in granules in plastids (such as amyloplasts or chloroplasts)

Question 18

is glycogen animal or plant based?

Answer 18

animal-based (and fungi)
-main energy storage polysaccharide

Question 19

what glucose monomer is glycogen made of?

Answer 19

α glucose

Question 20

what glycosidic bonds does glycogen have?

Answer 20

α 1,4 and 1,6 tf a branched molecule

Question 21

is glycogen branched or unbranched?

Answer 21

branched (not coiled)

Question 22

how are amylopectin and glycogen similar and different?

Answer 22

similarities
-both have α 1,4 and 1,6 glycosidic bonds
-both branched
differences
-glycogen has more branches (tf more terminal glucose molecules)

Question 23

what are the 4 properties of glycogen?

Answer 23

same as starch
-insoluble
-compact granule
-branching
-large molecule

Question 24

what is the effect of glycogen’s insolubility on its function?

Answer 24

no effect on water potential

Question 25

what is the effect of glycogen's compactness?

Answer 25

takes up little space

Question 26

what is the effect of glycogen's many branches?

Answer 26

multiple sites for rapid hydrolysis

Question 27

what is the effect of glycogen's size?

Answer 27

it is a large molecule tf there are many glucose molecules for respiration

Question 28

is cellulose animal or plant based?

Answer 28

used in plant cell walls

Question 29

what glucose monomer is cellulose made up of?

Answer 29

β glucose

Question 29

what shape is cellulose?

Answer 29

long chains of β glucose (β pleated sheet)

Question 29

what is the structure of cellulose?

Answer 29

straight, unbranched chains run parallel to each other due to β glucose inverting alternately, allowing hydrogen bonds to form between the chains

Question 30

what glycosidic bonds does cellulose have?

Answer 30

β 1,4

Question 30

what must be done for glycosidic bonds to form in cellulose?

Answer 30

in order to form the β 1,4 glycosidic bond, consecutive β glucose molecules must be rotated 180° to each other

Question 30

where is cellulose used?

Answer 30

in plant cell wall

Question 31

which part of the structure in cellulose allows hydrogen bonds to form?

Answer 31

straight unbranched chains run parallel to one another due to β-glucose inverting alternately

Question 31

what glycosidic bonds does cellulose have??

Answer 31

1-4 glycosidic bond

Question 32

what do hydrogen bonds provide in cellulose?

Answer 32

they provide strength as they produce microfibrils of 60-70 chains

Question 32

what is the structure of cellulose?

Answer 32

straight, unbranched chains run parallel to another due to β-glucose inverting alternately (this allows hydrogen bonds to form) (β-pleated sheet)

Question 33

is cellulose soluble or insoluble?

Answer 33

insoluble (so it doesn't affect water potential) but permeable to solutes

Question 33

how do hydrogen bonds provide strength in cellulose?

Answer 33

as they produce microfibrils of 60-70 chains (strengthens them and prevents them from spiralling

Question 34

is cellulose soluble or insoluble?

Answer 34

insoluble so it doesn't affect water potential (but permeable to solutes)

Question 35

how do hydrogen bonds provide strength?

Answer 35

as they produce microfibrils of 60-70 chains

Question 35

what gives extra strength in cellulose?

Answer 35

microfibrils run in different directions

Question 36

is cellulose soluble or insoluble?

Answer 36

insoluble so it doesn't affect water potential, but permeable to solutes

Question 36

why are the chains straight in cellulose?

Answer 36

due to the hydroxyl and hydrogen bonds being inverted on carbon 1 of β-glucose (this results in the rotation of successive β-glucose molecules by 180 for glycosidic bond formation between them

Question 37

what gives extra strength in cellulose?

Answer 37

microfibrils run in different directions for extra strength

Question 37

what is the test for starch?

Answer 37

iodine in potassium iodine solution

Question 38

what glycosidic bonds does cellulose have?

Answer 38

1,4

Question 38

what is the colour change when starch is tested?

Answer 38

yellow brown--> blue black

Question 39

what is the test for starch?

Answer 39

iodine in potassium iodine solution

Question 39

what is the procedure for testing starch?

Answer 39

- a sample is placed into a test tube at room temp - couple of drops of iodine are added and stirred -colour change iodine I2 forms triiodide ions (I3-), which enter amylose chains

Question 40

what is the colour change for starch?

Answer 40

orange-yellow ---> blue/black if starch is present

Question 41

how do you test for starch?

Answer 41

-at room temperature, a sample is placed into a set tube -add a few drops of iodine -stir

Question 43

what qualities make starch and glycogen good storage polysaccharides?

Answer 43

-compact -insoluble

Question 44

explain the qualities which make starch and glycogen good storage molecules

Answer 44

-compact large quantities can be stored -insoluble have no osmotic effect (unlike glucose which lowers the water potential of a cell causing water to move into the cells)

Question 45

what are plastids?

Answer 45

membrane bound organelles that can be found in plant cells with specialised function

Question 46

which cells have a high conc of glycogen?

Answer 46

liver and muscle cells (present as visible granules) - as cellular respiration is high in these cells

Question 47

what is a microfibril?

Answer 47

60-70 cellulose molecules

Question 48

is the test for starch qualitative or quantitative?

Answer 48

qualitative- only identifies presence not concentration

Question 49

is the test for reducing and non-reducing sugars quantitative or qualitative?

Answer 49

qualitative- (semi quantitative- colour change gives indication of conc)