Carbohydrates 2: polysaccharides

Question 2

Polysaccharides

Answer 2

Many monosaccharides can be linked by glycosidic bonds to form polysaccharides.
E.g glycogen, cellulose & starch

Question 3

Polysaccharides are

Answer 3

Variable in length
Branched or unbranched
Straight or coiled
Folded ideal for energy storage

Question 4

Polysaccharide Ideal for energy storage:

Answer 4

They can form very compact molecules which takes up less space.
They are physically and chemically inactive so they do not interfere which other cell functions of cell.
They are not very soluble so have almost no effect on water potential within cell & cause osmotic movements.

Question 5

Starch

Answer 5

Starch is made up of many α glucose residues linked by glycosidic bonds.

Question 6

Starch is a mixture of 2 compounds:

Answer 6

Amylose & amylopectin

Question 7

Function of starch

Answer 7

Energy storage molecule in plant cells

Question 8

Starch - structure related to function: compact

Answer 8

So more glucose can be stored in less space in a cell

Question 9

Starch - structure related to function: insoluble

Answer 9

So cannot leave the cell easily & it does not have an osmotic effect

Question 10

Starch - structure related to function: unreactive

Answer 10

So it does not get involved in chemical reactions of the cell

Question 11

Starch - structure related to function: rapidly hydrolysed

Answer 11

Amylose and amylopectin can be rapidly hydrolysed by enzymes into maltose as they are highly branched

Question 12

Glycogen

Answer 12

Made up of α glucose residues
Branches formed due to 1,6-glycosidic bonds
1,4 - glycosidic bonds are found in unbranched part
Branches formed due after 8 to 10 residues

Question 13

Glycogen - structure related to function: compact

Answer 13

Glycogen is compact so it allows storage of large quantities of glucose in a small space

Question 14

Glycogen - structure related to function: Insoluble

Answer 14

It is insoluble so it cannot leave the cell easily and does not have an osmotic effect

Question 15

Glycogen - structure related to function: unreactive

Answer 15

It is relatively unreactive so it does not get involved in chemical reactions in cell

Question 16

Glycogen - structure related to function: highly branched

Answer 16

It is highly branched so can be rapidly hydrolysed by enzymes into glucose and used for respiration in cells

Question 17

Polysaccharides & energy: insoluble

Answer 17

They cannot leave the cell
Have no osmotic effect. So, cells can store lots of polysaccharides without the need for osmoregulation

Question 18

Polysaccharides & energy: hydrolysed by enzymes

Answer 18

can be quickly hydrolysed by enzymes into glucose and used for respiration in cells

Question 19

Polysaccharides & energy: relatively unreactive

Answer 19

They do not get involved in other metabolic reactions in cells

Question 20

Polysaccharides & energy: compact

Answer 20

A lot of glucose is stored in small space within the cell

Question 21

Source: cellulose

Answer 21

Plant

Question 22

Source: starch (amylose)

Answer 22

Plant

Question 23

Source: starch (amylopectin)

Answer 23

Plant

Question 24

Source: glycogen

Answer 24

Animal

Question 25

Subunits: cellulose

Answer 25

β-glucose

Question 26

Subunits: starch (amylose)

Answer 26

α-glucose

Question 27

Subunits: starch (amylopectin)

Answer 27

α-glucose

Question 28

Subunits: glycogen

Answer 28

α-glucose

Question 29

Bonds: cellulose

Answer 29

1,4

Question 30

Bonds: starch (amylose)

Answer 30

1,4

Question 31

Bonds: starch (amylopectin)

Answer 31

1,4 & 1,6

Question 32

Bonds: glycogen

Answer 32

1,4 & 1,6

Question 33

Branches: cellulose

Answer 33

No

Question 34

Branches: starch (amylose)

Answer 34

No

Question 35

Branches: starch (amylopectin)

Answer 35

Yes
(-per 20 subunits)

Question 36

Branches: glycogen

Answer 36

Yes
(-per 10 subunits)