Biological Molecules - 3.1.2.4 Polysaccharides structure and function and the starch test Flashcards Preview

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Flashcards in Biological Molecules - 3.1.2.4 Polysaccharides structure and function and the starch test Deck (31)
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1

How is the structure of cellulose suited to its function?

  • β-Glucose molecules can form long straight chains
  • Parallel chains of cellulose form hydrogen bond 'cross links' which add strength
  • Cellulose is arranged into microfibrils and then fibres, which add yet more strength

2

Which type of bond forms between adjacent α-glucose molecules in glycogen?

α 1-4 glycosidic bonds

3

Unbranched starch (amylose) coils into a...

compact helix structure

4

What test is described below:

Place 2 cm3 of the sample being tested into a test tube

Add 2 drops of iodine solution

A blue black colouration indicates a positive result

The test for starch

5

What form does starch take within plant cells?

Starch grains

6

Which type of bond forms between branching α-glucose molecules in glycogen?

α 1-6 glycosidic bonds

7

Which type of bond forms between unbranched starch (amylose) molecules?

α 1-4 glycosidic bonds

8

How is glycogen different to starch?

Glycogen has many more branches

9

Which type of organism contains starch?

Plants

10

What form does glycogen take in cells?

granules within muscle and liver cells

11

What type of reaction occurs when monosaccharides join?

Condensation reaction

12

How would you test for starch?

  1. Place 2 cm3 of the sample being tested into a test tube
  2. Add 2 drops of iodine solution
  3. A blue black colouration indicates a positive result

13

Cellulose microfibrils are grouped are arranged in parallel groups called...

fibres

14

Which monosaccharide is cellulose made from?

β-Glucose

15

How does the structure of glycogen make it suited to its function?

  • It is insoluble so does not cause water to move into the cell via osmosis
  • It is large so does not diffuse out of animal cells
  • It is compact
  • It forms α-Glucose when hydrolysed for respiration
  • Many more branches than starch allow α-Glucose to be released faster from glycogen

17

What is the function of glycogen?

an energy store for animal and bacterial cells

18

The coiled helix structure of unbranched starch (amylose) is held in place by...

hydrogen bonds

19

What is the function of cellulose?

  • Cellulose is a major component of plant cell walls and provides rigidity to plant cells
  • Stops plant cells bursting when water enters

20

How are parallel chains of cellulose held together?

hydrogen bonds

21

What structure does cellulose take?

Long unbranched chains that run parallel to each other

22

Which type of bond forms between branched starch (amylopectin) molecules?

α 1-6 glycosidic bonds

23

Which type of monosaccharide is starch made from?

α-Glucose

24

Which type of bonds join β-Glucose molecules when they form cellulose?

β 1-4 glycosidic bonds

25

Cellulose chains are arranged in parallel groups called....

microfibrils

26

Why does glycogen require more branches than starch?

Animal cells require more energy to function

27

How does the structure of starch make it suited to its function?

  • It is insoluble so does not cause water to move into the cell via osmosis
  • It is large so does not diffuse out of plant cells
  • It is compact
  • It forms α-Glucose when hydrolysed for respiration
  • Many branches allow α-Glucose to be released fast

28

Name the 3 types of polysaccharide

Starch (amylose and amylopectin)

Glycogen

Cellulose

29

What is the main function of starch?

energy storage in plant cells

30

Describe the structure of glycogen

POLYMER of alpha glucose

joined by glycosidic bonds

branched structure

31

How does glycogen act as a source of energy?

branched chains are HYDROLYSED

into glucose

used in respiration 

32

Which type of monosaccharide is glycogen made from?

α-Glucose

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