Biological molecules: Starch, Glycogen And Cellulose Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is starch made of?

A

Chains of alpha glucose monosaccharides linked by glycosidic bonds that are formed by condensation reactions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How is the helix of a starch molecule held in place?

A

There are hydrogen bonds between the OH groups as they are pointing inwards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the two types of starch?

A

Amylose and amylopectin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

For amylopectin,
What monomer is it made from?
What are the bonds between the monomers?
What is it’s shape?

A
  • alpha glucose
  • 1,4 glycosidic bond
  • helix shape
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

For amylopectin,
What monomer is it made from?
What are the bonds between the monomers?
What is it’s shape?

A
  • alpha glucose
  • 1,4 and 1,6 glycosidic bonds
  • helix shape with branches
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the 5 ways the structure of starch allows its main role to be energy storage

A
  • its insoluble so doesn’t affect water potential so water’s not drawn into cells by osmosis
  • its largeness and insolubility stops it diffusing out of cells
  • its compact so a lot can be stored in a small space
  • when hydrolysed it forms alpha glucose which is both easily transported and readily used in respiration
  • amylopectin ( the branched form) has many ends which can be acted upon by enzymes simultaneously meaning glucose monomers are released very rapidly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What cells is starch never found in?

A

Animal cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where is glycogen found?

A

Animal and bacterial cells ( never plant cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is the structure of glycogen different to starch?

A

Its more highly branched but has shorter chains than starch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How and where is glycogen stored in animals?

A

As small granules in the muscles and liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why is the mass of carbohydrate stored in animals relatively small?

A

Because fat is the main storage molecule in animals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why is the structure of glycogen suited for its storage?

A
  • its insoluble so doesn’t draw water into cells by osmosis and doesn’t diffuse out of cells
  • its compact so a lot of it can be stored in a small space
  • its more highly branched than starch and so has more ends that can be acted on simultaneously by enzymes and so is more rapidly broke down into glucose monomers which are used in respiration. Important to animals that have a higher metabolic rate and so higher respiratory rate than animals as they are more active
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What monomers make up cellulose?

A

Beta glucose monomers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What cells is cellulose found in?

A

Plant cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the name of the bonds between the monomers of cellulose

A

Beta 1,4 bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the structure of cellulose like?

A
  • it has a straight chain
  • its unbranched
  • every other beta glucose molecule flips by 180 degrees
17
Q

How is cellulose a good structural material in a plant cell wall?

A

Because between each beta glucose chain, there are weak hydrogen bonds caused by the polarity of the hydrogen bonding with oxygen. As there are many of them, the overall number makes a large contribution to strengthening cellulose

18
Q

What are microfibrils?

A

The cellulose molecules once they have been grouped together

19
Q

What are fibres?

A

When the microfibrils have been arranged into parallel groups

20
Q

How is cellulose useful in plant cells?

A
  • provides rigidity in plant cells
  • prevents plant cells bursting when water enters by osmosis
  • maintains turgidity and rigidity in the cells so the stems and leaves can have maximised surface area for photosynthesis
21
Q

How does cellulose keep the cell wall from bursting?

A

it exerts an inward pressure that stops any further influx of water and so making non woody parts of the plant semi rigid

22
Q

Why is it important that cellulose maintains stems and leaves in a turgid state?

A

So that they can provide the maximum surface area for photosynthesis

23
Q

How is the structure of cellulose suited to its function of providing support and rigidity?

A
  1. cellulose molecules are made of beta glucose and so form straight unbranched chains
  2. These molecular chains run parallel to each other and are cross linked by hydrogen bonds that add collective strength
  3. These molecules are grouped to form microfibrils which in turn are grouped to form fibres all of which provides yet more strength