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

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1
Q

How is the structure of cellulose suited to its function?

A
  • 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
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2
Q

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

A

α 1-4 glycosidic bonds

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3
Q

Unbranched starch (amylose) coils into a…

A

compact helix structure

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4
Q

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

A

The test for starch

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5
Q

What form does starch take within plant cells?

A

Starch grains

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6
Q

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

A

α 1-6 glycosidic bonds

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7
Q

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

A

α 1-4 glycosidic bonds

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8
Q

How is glycogen different to starch?

A

Glycogen has many more branches

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9
Q

Which type of organism contains starch?

A

Plants

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10
Q

What form does glycogen take in cells?

A

granules within muscle and liver cells

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11
Q

What type of reaction occurs when monosaccharides join?

A

Condensation reaction

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12
Q

How would you test for starch?

A
  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
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13
Q

Cellulose microfibrils are grouped are arranged in parallel groups called…

A

fibres

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14
Q

Which monosaccharide is cellulose made from?

A

β-Glucose

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15
Q

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

A
  • 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
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17
Q

What is the function of glycogen?

A

an energy store for animal and bacterial cells

18
Q

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

A

hydrogen bonds

19
Q

What is the function of cellulose?

A
  • Cellulose is a major component of plant cell walls and provides rigidity to plant cells
  • Stops plant cells bursting when water enters
20
Q

How are parallel chains of cellulose held together?

A

hydrogen bonds

21
Q

What structure does cellulose take?

A

Long unbranched chains that run parallel to each other

22
Q

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

A

α 1-6 glycosidic bonds

23
Q

Which type of monosaccharide is starch made from?

A

α-Glucose

24
Q

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

A

β 1-4 glycosidic bonds

25
Q

Cellulose chains are arranged in parallel groups called….

A

microfibrils

26
Q

Why does glycogen require more branches than starch?

A

Animal cells require more energy to function

27
Q

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

A
  • 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
Q

Name the 3 types of polysaccharide

A

Starch (amylose and amylopectin)

Glycogen

Cellulose

29
Q

What is the main function of starch?

A

energy storage in plant cells

30
Q

Describe the structure of glycogen

A

POLYMER of alpha glucose

joined by glycosidic bonds

branched structure

31
Q

How does glycogen act as a source of energy?

A

branched chains are HYDROLYSED

into glucose

used in respiration

32
Q

Which type of monosaccharide is glycogen made from?

A

α-Glucose