1. Carbohydrates Flashcards

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1
Q

An individual sugar molecule is called a…

A

monosaccharide

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2
Q

Name a structural polysaccharide

A

Cellulose (plant cell walls)

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3
Q

What happens during hydrolysis

A

A water molecule is taken in to break down a chain of molecules.

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4
Q

Polysaccharides are large. This means that they are…

A

insoluble (will not dissolve)

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5
Q

Identify the monosaccharide

A

Galactose

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6
Q

When many monosaccharides join together, they form a…

A

polysaccharide

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7
Q

Which elements make up carbohydrates?

A

Carbon

Hydrogen

Oxygen

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8
Q

When 2 monosaccharides join together, they form a…

A

disaccharide

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9
Q

What happens during a condensation reaction?

A

A water molecule is released from the reacting molecules

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10
Q

How many covalent bonds does carbon make?

A

4

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11
Q

Which type of reaction takes place when two monosaccharides join together?

A

Condensation Reaction

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12
Q

Identify the monosaccharide

A

α-Glucose

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13
Q

A 3 carbon sugar is called a…

A

triose

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14
Q

A 6 carbon sugar is called a…

A

hexose

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15
Q

Name the bond that forms between two monosaccharides

A

Glycosidic bond

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16
Q

An individual biological molecule is called a…

A

monomer

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17
Q

Which type of reaction takes place when a disaccharide or polysaccharide is broken down?

A

Hydrolysis

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18
Q

Identify the monosaccharide

A

Fructose

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19
Q

Name 3 common disaccharides

A

Maltose (glucose + glucose)

Sucrose (glucose + fructose)

Lactose (glucose + galactose)

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20
Q

What is an isomer?

A

Molecules that have the same chemical formula but whose molecules are arranged differently.

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21
Q

Long chains of repeating molecules are called…

A

polymers

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22
Q

Glucose + Fructose –> _________

A

Glucose + Fructose –> Sucrose

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23
Q

The general chemical formula of a monosaccharide is…

A

(CH2O)nwhere n is the number of carbon atoms.

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24
Q

Glucose + Glucose –> _________

A

Glucose + Glucose –> Maltose

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25
Q

Identify the monosaccharide

A

β-Glucose

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26
Q

A 7 carbon sugar is called a…

A

heptose

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27
Q

Name the type of monosaccharide

Give its formula

A

Heptose

(CH2O)7

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28
Q

A molecule containing carbon is called an…

A

organic molecule

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29
Q

Name 4 common hexose monomers

A

α-Glucose

β-Glucose

Galactose

Fructose

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30
Q

Name 2 common storage polysaccharides

A

Glycogen

Starch

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31
Q

Name the type of monosaccharide

Give its formula

A

Triose

(CH2O)3

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32
Q

Which 4 elements make up most biological molecules?

A

Carbon

Hydrogen

Oxygen

Nitrogen

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33
Q

Glucose + Galactose –> _________

A

Glucose + Galactose –> Lactose

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34
Q

Polysaccharides are used in cells for _____________ and ____________

A

Storage (energy)

Structure (cell walls)

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35
Q

name the monomer that makes up maltose

A

glucose

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36
Q

sucrose hydrolysis produces..

A

fructose and glucose

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37
Q

How is the structure of cellulose suited to its function?

A
Long, straight/unbranched chains of β glucose
Joined by hydrogen bonding
To form (micro/macro)fibrils;
Provides rigidity/strength;
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38
Q

What other enzyme is required for the complete digestion of starch?

A

amylase and maltase

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39
Q

Give 2 differences between the structure of cellulose and glycogen

A

cellulose moleculesstraightchains; glycogen branched

cellulose beta glucose; glycogen alpha glucose

celluose molecules straight chains; glycogen coiled

celluose has only 1, 4 glycosidic bonds; glycogen has 1,4 and 1,6 bonds

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40
Q

Describe and explain 2 features of starch that makes it a good storage molecule

A
coiled/helical making it compact
insoluble so does not affect the WP of cells
LArge so cant cross the cell membrane
Branched so more ends for enzyme action

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41
Q

What bonds do amylose, amylopectin, glycogen and cellulose contain? numbers included

A

Amylose - 1-4 Alpha
Amylopectin - 1-4 and 1-6 Alpha
Glycogen - 1-4 and 1-6 Alpha
Cellulose - 1-4 beta

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42
Q

Describe how lactose is formed

A

glucose and galactose

join by condensation reaction

through a glycosidic bond

43
Q

test which tests for starch?

A

iodine

44
Q

What does it mean if a food sample turns benedicts solution this colour?

A

Low concentraiton of reducing sugar is present

45
Q

What is a reducing sugar?

A

A sugar that can give an electron to the Copper (II) Sulphate found in Benedict’s reagent to make it form a red Copper (I) Oxide precipitate.

46
Q

How would you carry out a Benedict’s rest for a reducing sugar

A
  • Add 2cm3 of the food sample to a test tube
  • Add an equal volume of Benedict’s Reagent
  • Heat the mixture in a boiling water bath for 5 minutes
  • Observe colour change - positive - brick-red precipitate
47
Q

What do the following instructions describe a test for?

  • Boil the sample with hydrochloric acid
  • This will hydrolyse any disaccharide into 2 monosaccharides
  • Cool solution and neutralise with sodium hydrogen carbonate
  • Add Benedict’s Reagent and heat
  • Observe colour change - brick red precipitate
A

Non-Reducing Sugars

48
Q

Which two reducing sugars are released when sucrose is hydrolysed?

A

Glucose

Fructose

49
Q

What do we mean when we say that the Benedict’s Test for Reducing Sugars is ‘semi-quantitative’?

A

That the colour of the result can be used toestimate the approximate amount of reducing sugar in a sample

50
Q

What does it mean if a food sample turns benedicts solution this colour?

A

No reducing sugar is present

51
Q

Name a disaccharide that is a non-reducing sugar

A

sucrose

52
Q

What does it mean if a food sample turns benedicts solution this colour?

A

Medium concentration of reducing sugar is present

53
Q

What does it mean if a food sample turns benedicts solution this colour?

A

High concentration of reducing sugar is present

54
Q

During a Non-Reducing sugar test why do we need to neutralise the food sample after heating it in acid?

A

Because Benedict’s reagent will not work in acidic conditions (ideally alkaline)

55
Q

What do the following instructions describe a test for?

  • Add 2cm3 of the food sample to a test tube
  • Add an equal volume of Benedict’s Reagent
  • Heat the mixture in a boiling water bath for 5 minutes
  • Observe colour change
A

A Benedict’s Test for a Reducing Sugar

56
Q

What does it mean if a food sample turns benedicts solution this colour?

A

Very low concentraiton of reducing sugar is present

57
Q

What does this picture show?

A

The results of Benedict’s test according to the concentration of reducing sugar present

58
Q

What is a Non-Reducing Sugar?

A

A sugar that is unable to give an electron to the Copper (II) Sulphate in Benedict’s Reagent so itis unable to form a red Copper (I) Oxide precipitate

59
Q

Which types of sugars are all reducing sugars?

A

Monosaccharides

60
Q

How would you test for a Non-Reducing Sugar?

A
  • Boil the sample with hydrochloric acid
  • This will hydrolyse any disaccharide into 2 monosaccharides
  • Cool solution and neutralise with sodium hydrogen carbonate
  • Add Benedict’s Reagent and heat
  • Observe colour change
61
Q

The process of breaking a disaccharide up into 2 monosaccharides is called…

A

Hydrolysis

62
Q

Name 2 common disaccharides that are reducing sugars

A

Maltose

Lactose

63
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
64
Q

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

A

α 1-4 glycosidic bonds

65
Q

Unbranched starch (amylose) coils into a…

A

compact helix structure

66
Q

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

A

α 1-6 glycosidic bonds

67
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

68
Q

Identify the polysaccharide

A

Starch (amylose)

69
Q

Identify the polysaccharide

A

Starch (amylopectin)

70
Q

What form does starch take within plant cells?

A

Starch grains

71
Q

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

A

α 1-4 glycosidic bonds

72
Q

Identify the polysaccharide

A

Cellulose

73
Q

How is glycogen different to starch?

A

Glycogen has many more branches

74
Q

What type of reaction occurs when monosaccharides join?

A

Condensation reaction

75
Q

Which type of organism contains starch?

A

Plants

76
Q

Identify the polysaccharide

A

Glycogen (more branches than starch)

77
Q

What form does glycogen take in cells?

A

granules within muscle and liver cells

78
Q

How would you test for starch?

A
  • 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
79
Q

Cellulose microfibrils are grouped are arranged in parallel groups called…

A

fibres

80
Q

Which monosaccharide is cellulose made from?

A

β-Glucose

81
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 animalcells
  • 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
82
Q

What is the function of glycogen?

A

an energy store for animal and bacterial cells

83
Q

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

A

hydrogen bonds

84
Q

Which type of monosaccharide is glycogen made from?

A

α-Glucose

85
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
86
Q

How are parallel chains of cellulose held together?

A

hydrogen bonds

87
Q

What structure does cellulose take?

A

Long unbranched chains that run parallel to each other

88
Q

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

A

α 1-6 glycosidic bonds

89
Q

Which type of monosaccharide is starch made from?

A

α-Glucose

90
Q

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

A

β 1-4 glycosidic bonds

91
Q

Cellulose chains are arranged in parallel groups called….

A

microfibrils

92
Q

Why does glycogen require more branches than starch?

A

Animal cells require more energy to function

93
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
94
Q

Name the 3 types of polysaccharide

A

Starch (amylose and amylopectin)

Glycogen

Cellulose

95
Q

What is the main function of starch?

A

energy storage in plant cells

96
Q

Describe the structure of glycogen

A

POLYMER of alpha glucose

joined by glycosidic bonds

branched structure

97
Q

How does glycogen act as a source of energy?

A

branched chains are HYDROLYSED

into glucose

used in respiration

98
Q

Starch

A
  • Found as grains in plant cells - especially in seeds and storage organs
  • Major energy source in the diet
  • Not found in animal cells
99
Q

Amylose

A
  • Long unbranched chains of a-glucose
  • Angle of glycosidic bonds give it coiled structure
  • Compact - therefore good for storage as you can fit a lot in a small space
  • Hydrogen bonds help hold structure
100
Q

Amylopectin

A
  • Long unbranched chain of a-glucose

- Branches mean there are many free end to allow enzymes to hydrolyse glycosidic bonds easily

101
Q

Starch structure and functions

A
  • Plants store excess glucose as starch
  • Insoluble- doesn’t affect water potential
  • Large and compact - allows a lot in small space
  • Large molecule - difficult to leave cell - good storage molecule
102
Q

Glycogen

A
  • Excess glucose in animals
  • A polymer of a-glucose with 1-4 bond and 1-6 glycosidic branches
  • More highly branched, glucose released quickly by hydrolysis in muscles and liver
  • Making glycogen from glucose is glycogenesis
103
Q

Cellulose

A
  • Polymer of B-glucose
  • 1-4 b-glycosidic bonds
  • Long unbranched chains
  • Glucose are all rotated 180 degrees
  • Straight cellulose chains
104
Q

Cellulose structures

A
  • The straight cellulose chains are held together by many weak HYDROGEN bonds. Large number of these make the microfibrils very strong.
  • Prevents plant cells bursting by exerting an inward pressure - TURGIDTY