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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
Why is the yoghurt cooled to 5?
serving slows enzyme activity
24
What does the lactobacillus ferment lactose into?
lactic acid
25
What must farmers make on their farms?
profit
26
How do farmers maximise profit on farms?
control environment to increase yield
27
Why are greenhouses preferable over fields?
easy to control factors
28
List factors of greenhouse
- artificial heating - artificial lighting - co2 - watering
29
What do greenhouses and polythene tunnels provide?
enhanced conditions
30
What are greenhouses and polythene tunnels made of?
transparent material
31
How does the transparent material enhance conditions?
allows sufficient natural light
32
How does additional lighting enhance conditions?
provides 'longer day' in winter
33
How does greenhouse effect enhance conditions?
raises temperature
34
How does burning of fossil fuels or wood enhance conditions?
raises temperature and produces co2 and water vapour
35
How does added water vapour enhance conditions?
maintains moist atmosphere and reduces water loss by transpiration
36
How do fertilisers increase growth?
provide elements for plants
37
What is magnesium used for?
chlorophyll
38
What are nitrates used for?
proteins
39
Define organic fertilisers
made from faeces of animals, compost of legumes and straw
40
Define inorganic fertilisers
inorganic compounds formulated to have concentration of ion
41
What are the advantages of organic fertilisers?
- improves soil structure - greater range of minerals - releases over a longer period of time - less costly
42
Which type of fertiliser improves soil structure?
organic
43
Which type of fertiliser has a greater range of minerals?
organic
44
Which type of fertiliser releases minerals over a longer period of time?
organic
45
Which type of fertiliser is less cost to farmer?
organic
46
What are the disadvantages of organic fertilisers?
- slow acting - bulkier - may contain pests
47
Which fertiliser is slow acting?
organic
48
Which fertiliser is more difficult to apply?
organic
49
Which fertiliser may contain pests?
organic
50
What are the advantages of inorganic fertilisers?
- release ions immediately - contents known - easy to apply
51
Which fertiliser is fast acting?
inorganic
52
Which fertiliser has known contents?
inorganic
53
Which fertiliser is easy to apply?
inorganic
54
What are the disadvantages of inorganic fertilisers?
- eutrophication - regular application
55
Which fertiliser can cause eutrophication?
inorganic
56
Which fertiliser requires regular applocation?
inorganic
57
What does pests do?
organisms that reduce yield of crop plants or stock animals
58
How do farmers control pests?
pesticides and biological control
59
What do herbicides kill?
plant pests
60
What do insecticides kill?
kills insects
61
What do fungicides kill?
kill fungi
62
What do molluscicides kill?
kill molluscs (snails and slugs)
63
What are pesticides used to do?
kill pests and improve crop yield
64
When are pests are problem?
present sufficient numbers to cause economic damage
65
How does biological control reduce the number of pests?
predator species to reduce number of pests
66
What is the feature of biological control?
never eradicates pest
67
What is the aim of biological control?
reduce number so no longer economic damage
68
What effect does a natural predator have?
ladybirds can be used to control populations of aphids in orange groves
69
What effect does a herbivore have?
eats plants such as prickly pear cactus
70
What effect does a parasite have?
wasp lays eggs in whitefly eggs to reduce population
71
What effect does a pathogenic microorganism have?
fall in pest numbers
72
What effect does sterile males have?
no offspring so pest numbers fall
73
What effect does pheromones have?
sex hormones released to attract, then collected and destroyed
74
What are the advantages of pesticides?
- reduces population instantly - can kill whole population
75
What are the disadvantages of pesticides?
- cost - not specific - become resistant - chemical can concentrate higher up in food chain
76
What are the advantages of biological control?
- only introduce once - only one cost - specific - no resistance - no effect on other animals
77
What are the disadvantages of biological control?
- takes time - not all killed - expensive if re populating
78
What is the role of the cooling jacket?
removes heat energy - stops overheating
79
What is the role of the air filter?
filters air - maintains sterile conditions
80
What is the role of stirrers?
keep well stirred - oxygenate all parts - prevent micro-organisms settling
81
What is the role of growth medium?
contains all glucose and amino acids for growth
82
What is the role of the super heated steam?
kills unwanted micro-organisms
83
What are commonly farmed commercial species of fish?
salmon trout
84
What do farmers feed fish?
high lipid and protein food
85
Why do farmers feed fish high lipid and protein food?
promote rapid growth
86
Why do farmers feed fish little and often?
so it all gets eaten
87
What issue would be caused if not all food was eaten?
decomposes
88
What is interspecific competition?
competition between different species
89
What is intraspecific competition?
competition in same species for resources
90
What is predation?
big fish prey on smaller fish
91
What happens if several species are in on pond?
interspecific predation
92
What is the solution to several species in one pond?
separate species use nets
93
What happens if too many fish in on pond?
intraspecific competition infectious disease
94
What is the solution to too many fish in one pond?
- separate by age and size - remove dead or ill fish - antibiotics - antifungals
95
Why is it important to remove ill or dead fish quickly?
pathogens spread quickly
96
How will fish affect the environment when they escape?
compete or interbreed with local species - reduce biodiversity
97
How will fish affect the environment in terms of disease?
can introduce parasites/pathogens to ecosystem
98
How do fish farms cause eutrophication?
- excess feed and waste
99
Define deforestation
clearance of large area of trees
100

iGCSE Biology (24 decks)

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