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iGCSE Biology > Harnessing Biology > Flashcards

Harnessing Biology Flashcards

1
Q

What is lactobacillus?

A

bacterial species used to make yoghurt

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2
Q

What is yeast?

A

unicellular fungi used to produce bread

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3
Q

What is the role of yeast in the production of bread?

A

respire anaerobically
- produce carbon dioxide which helps bread rise

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4
Q

What is the role of yeast in the production of beer?

A

respires anaerobically
- produces ethanol which is the alcohol in beer

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5
Q

What is the equation for anaerobic respiration in yeast?

A

glucose -> ethanol + carbon dioxide

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6
Q

What is the cell wall of yeast made of?

A

chitin

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7
Q

Describe an investigation for the role of anaerobic respiration in yeast in different conditions

A
  1. using hydrogen carbonate indicator
  2. add yeast to sugar solution to form a suspension
  3. add layer of oil
  4. connect this boiling tube to a second tube containing indicator using a delivery tube
  5. orange to yellow (incr. in CO2)
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8
Q

Describe the CORMMS plan for an investigation for the role of anaerobic respiration in yeast in different conditions

A

C - temp ; 30, 40, 50, 60, 70
O - yeast ; species, age, size
R - repeat each temp x3
M - volume of CO2
M - 5 mins
S - concentration/volume of sugar solution, pH

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9
Q

Why is the layer of oil necessary when investigating the role of anaerobic respiration in yeast in different conditions?

A

prevents oxygen from entering
means the yeast respires anaerobically

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9
Q

Why does the carbon dioxide level increase when investigating the role of anaerobic respiration in different conditions?

A

yeast are respiring anaerobically
producing carbon dioxide

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9
Q

What is another test for carbon dioxide?

A

limewater
clear to cloudy

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10
Q

What conditions can be changed when investigating the role of anaerobic respiration in different conditions?

A

temperature
conc of sugar
type of sugar

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11
Q

What is the role of lactobacillus in making yoghurt?

A
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12
Q

Describe the process of yoghurt production

A
  1. equipment sterilisation
  2. milk pasteurisation
  3. milk is homgenised
  4. cool the milk
  5. add live yog and mix
  6. pour into jars + cover
  7. incubate in warm
  8. yog is cooled
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13
Q

Why is the equipment used in yoghurt production sterilised?

A

kills unwanted bacteria and pathogens

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14
Q

What temperature is the equipment heated to in sterilisation?

A

95

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15
Q

Why is the milk pasteurised in yoghurt production?

A

kills unwanted bacteria and pathogens

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16
Q

What temperature is the milk heated to in pasteurisation?

A

85-95

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17
Q

Why is the milk homogenised in yoghurt production?

A

disperse any fat gobules

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18
Q

Why is the milk cooled in yoghurt production directly after the lactobacillus has been added?

A

so the bacteria lactobacillus does not denature due to high temperatures

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19
Q

What temperature is the milk cooled to in yoghurt production directly after the lactobacillus has been added?

A

40-45

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20
Q

How does the yoghurt thicken in yoghurt production?

A

lactobacillus digests milk proteins
respire anaerobically - produce lactic acid
lactic acid has a low pH
causes milk proteins to break down
COAGULATION - thickens

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21
Q

What is the thickening of the yoghurt caused by?

A

break down of milk proteins by lactobacillus which produces lactic acid with low pH

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22
Q

What is the thickening of yoghurt called?

A

coagulation

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23
Q

Why is the yoghurt cooled to 5?

A

serving
slows enzyme activity

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24
Q

What does the lactobacillus ferment lactose into?

A

lactic acid

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25
Q

What must farmers make on their farms?

A

profit

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26
Q

How do farmers maximise profit on farms?

A

control environment to increase yield

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27
Q

Why are greenhouses preferable over fields?

A

easy to control factors

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28
Q

List factors of greenhouse

A
  • artificial heating
  • artificial lighting
  • co2
  • watering
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29
Q

What do greenhouses and polythene tunnels provide?

A

enhanced conditions

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30
Q

What are greenhouses and polythene tunnels made of?

A

transparent material

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31
Q

How does the transparent material enhance conditions?

A

allows sufficient natural light

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32
Q

How does additional lighting enhance conditions?

A

provides ‘longer day’ in winter

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33
Q

How does greenhouse effect enhance conditions?

A

raises temperature

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34
Q

How does burning of fossil fuels or wood enhance conditions?

A

raises temperature and produces co2 and water vapour

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35
Q

How does added water vapour enhance conditions?

A

maintains moist atmosphere and reduces water loss by transpiration

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36
Q

How do fertilisers increase growth?

A

provide elements for plants

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37
Q

What is magnesium used for?

A

chlorophyll

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38
Q

What are nitrates used for?

A

proteins

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39
Q

Define organic fertilisers

A

made from faeces of animals, compost of legumes and straw

40
Q

Define inorganic fertilisers

A

inorganic compounds formulated to have concentration of ion

41
Q

What are the advantages of organic fertilisers?

A
  • improves soil structure
  • greater range of minerals
  • releases over a longer period of time
  • less costly
42
Q

Which type of fertiliser improves soil structure?

43
Q

Which type of fertiliser has a greater range of minerals?

44
Q

Which type of fertiliser releases minerals over a longer period of time?

45
Q

Which type of fertiliser is less cost to farmer?

46
Q

What are the disadvantages of organic fertilisers?

A
  • slow acting
  • bulkier
  • may contain pests
47
Q

Which fertiliser is slow acting?

48
Q

Which fertiliser is more difficult to apply?

49
Q

Which fertiliser may contain pests?

50
Q

What are the advantages of inorganic fertilisers?

A
  • release ions immediately
  • contents known
  • easy to apply
51
Q

Which fertiliser is fast acting?

52
Q

Which fertiliser has known contents?

53
Q

Which fertiliser is easy to apply?

54
Q

What are the disadvantages of inorganic fertilisers?

A
  • eutrophication
  • regular application
55
Q

Which fertiliser can cause eutrophication?

56
Q

Which fertiliser requires regular applocation?

57
Q

What does pests do?

A

organisms that reduce yield of crop plants or stock animals

58
Q

How do farmers control pests?

A

pesticides and biological control

59
Q

What do herbicides kill?

A

plant pests

60
Q

What do insecticides kill?

A

kills insects

61
Q

What do fungicides kill?

A

kill fungi

62
Q

What do molluscicides kill?

A

kill molluscs (snails and slugs)

63
Q

What are pesticides used to do?

A

kill pests and improve crop yield

64
Q

When are pests are problem?

A

present sufficient numbers to cause economic damage

65
Q

How does biological control reduce the number of pests?

A

predator species to reduce number of pests

66
Q

What is the feature of biological control?

A

never eradicates pest

67
Q

What is the aim of biological control?

A

reduce number so no longer economic damage

68
Q

What effect does a natural predator have?

A

ladybirds can be used to control populations of aphids in orange groves

69
Q

What effect does a herbivore have?

A

eats plants such as prickly pear cactus

70
Q

What effect does a parasite have?

A

wasp lays eggs in whitefly eggs to reduce population

71
Q

What effect does a pathogenic microorganism have?

A

fall in pest numbers

72
Q

What effect does sterile males have?

A

no offspring so pest numbers fall

73
Q

What effect does pheromones have?

A

sex hormones released to attract, then collected and destroyed

74
Q

What are the advantages of pesticides?

A
  • reduces population instantly
  • can kill whole population
75
Q

What are the disadvantages of pesticides?

A
  • cost
  • not specific
  • become resistant
  • chemical can concentrate higher up in food chain
76
Q

What are the advantages of biological control?

A
  • only introduce once
  • only one cost
  • specific
  • no resistance
  • no effect on other animals
77
Q

What are the disadvantages of biological control?

A
  • takes time
  • not all killed
  • expensive if re populating
78
Q

What is the role of the cooling jacket?

A

removes heat energy - stops overheating

79
Q

What is the role of the air filter?

A

filters air - maintains sterile conditions

80
Q

What is the role of stirrers?

A

keep well stirred - oxygenate all parts - prevent micro-organisms settling

81
Q

What is the role of growth medium?

A

contains all glucose and amino acids for growth

82
Q

What is the role of the super heated steam?

A

kills unwanted micro-organisms

83
Q

What are commonly farmed commercial species of fish?

A

salmon
trout

84
Q

What do farmers feed fish?

A

high lipid and protein food

85
Q

Why do farmers feed fish high lipid and protein food?

A

promote rapid growth

86
Q

Why do farmers feed fish little and often?

A

so it all gets eaten

87
Q

What issue would be caused if not all food was eaten?

A

decomposes

88
Q

What is interspecific competition?

A

competition between different species

89
Q

What is intraspecific competition?

A

competition in same species for resources

90
Q

What is predation?

A

big fish prey on smaller fish

91
Q

What happens if several species are in on pond?

A

interspecific
predation

92
Q

What is the solution to several species in one pond?

A

separate species
use nets

93
Q

What happens if too many fish in on pond?

A

intraspecific competition
infectious disease

94
Q

What is the solution to too many fish in one pond?

A
  • separate by age and size
  • remove dead or ill fish
  • antibiotics
  • antifungals
95
Q

Why is it important to remove ill or dead fish quickly?

A

pathogens spread quickly

96
Q

How will fish affect the environment when they escape?

A

compete or interbreed with local species - reduce biodiversity

97
Q

How will fish affect the environment in terms of disease?

A

can introduce parasites/pathogens to ecosystem

98
Q

How do fish farms cause eutrophication?

A
  • excess feed and waste
99
Q

Define deforestation

A

clearance of large area of trees

iGCSE Biology (22 decks)

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