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gsce biology > harnessing biology 5.10, 5.11, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9B, 4.3B, 4.4B, 4.18B, 4.12, 4.16, 4.17 > Flashcards

harnessing biology 5.10, 5.11, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9B, 4.3B, 4.4B, 4.18B, 4.12, 4.16, 4.17 Flashcards

1
Q

how to selectively breed:

A
  1. choose individuals with the desired feature
  2. let only these individuals reproduce
  3. choose the offspring that have the desired feature
  4. let only these individuals reproduce
  5. repeat steps 3 and 4 until you have produced a variety in which all the individuals show the desired feature
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2
Q

selective breeding:

A

produces different varieties however they are still the same species

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3
Q

what is the key to success when selectively breeding?

A

not allowing individuals with undesirable features to breed

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4
Q

how do farmers try and make a profit from their farms?

A

try and control the environment in a way to maximise the yield from crop plants and livestock

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5
Q

ways inside areas (greenhouses) can control factors chosen to grow crops:

A
  • artificial heating
  • artificial lighting
  • additional carbon dioxide in the air
  • regular watering
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6
Q

how do greenhouses and polythene tunnels provide enhanced conditions?

A
  • transparent material allowing sufficient natural light for photosynthesis
  • greenhouse effect raises temperature in the glasshouse
  • burning fissile fuels or wood raises the temperature when the external temperature is too low, produces carbon dioxide and water vapour
  • water vapour maintains a moist atmosphere so reduces water loss by transpiration

ALL INCREASING RATE OF PHOTOSYNTHESIS and increasing yield, by finding optimum conditions

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7
Q

what do fertilisers provide?

A

elements needed for plants to grow such as nitrates for proteins and magnesium for the production of chlorophyll

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8
Q

what are the two types of fertilisers?

A

organic
inorganic

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9
Q

what is an organic fertiliser?

A

made from the faeces of a range of animals, sometimes mixed with straw also compost from legumes such as clover

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10
Q

what is an inorganic fertiliser?

A

inorganic compounds carefully formulated to yield a specific concentration of a particular ion when applied according to the manufacture instructions

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11
Q

what are some advantages of organic fertilisers?

A
  • improves soil structure
  • greater range of minerals
  • releases minerals over a longer period of time
  • less cost to farmer, already available on the farm
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12
Q

what are some disadvantages of using organic fertiliser?

A

slow acting - had to be decomposed first
bulkier so more difficult than inorganic fertilisers to apply
may contain pests

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13
Q

what are some advantages of inorganic fertilisers?

A

mineral ions release immediately so fast acting
contents know
easy to apply

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14
Q

what are so disadvantages of inorganic fertilisers?

A

can lead to eutrophication as fertiliser is soluble
requires regular reapplication

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15
Q

how else can you replace lost nitrates?

A

nitrogen fixing plants :
grow a legume crop like clover in a field, they have nitrogen fixing bacteria in nodules on their roots, they convert nitrogen gas in air into ammonium ions

some of this is passed to the plants which use it to make proteins, when the crop is ploughed the protein and bacteria is broken down (decomposed) ammonium is released into soil
ammonium is converted to nitrate by nitrifying bacteria

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16
Q

what are pests?

A

they are organisms that reduce the yield of crop plants or stock animals

causing economic damage

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17
Q

how can pests be controlled?

A

chemical called pesticides
use another organism to reduce the number of pests - biological control

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18
Q

what are pesticides?

A

used to kill specific pests and improve the yield from the crops and livestock

can damage the ecosystem as often the pesticide molecules are simply passed higher up the food chain and become concentrated in the tissues of top carnivores

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19
Q

examples of types of pesticides:

A

herbicides : kill plant pests
insecticide : kill insects
fungicides : kill fungi
molluscicides : kill molluscs

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20
Q

how does biological control of pests work?

A

uses predator species rather than a toxic chemical so reduce the number of pests

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21
Q

what is the slight downside to biological control?

A

it never eradicates a pest as if the organism killed off all the pests then it would die from lack of food so the aim is to reduce pest numbers

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22
Q

what’s the effect of introducing a natural predator?

A

ladybirds can be used to control the population of aphids in orange groves

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23
Q

what’s the effect of introducing a herbivore?

A

eats pest plants such a prickly pear cactus in australia

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24
Q

what’s the effect of introducing a parasite?

A

wasp encarsia lays its eggs in whitefly eggs and reduces the population

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25
Q

what’s the effect of introducing a pathogenic microorganism?

A

a fall in pest numbed such as that caused by the myxomatosis virus on rabbit population in australia

26
Q

what’s the effect of introducing sterile males?

A

mate with females but produce no offspring so pest numbers fall

27
Q

what’s the effect of using pheromones?

A

sex hormones released attract males or females which are then collected and destroyed reducing the reproductive potential of the population

28
Q

what’s the advantages of using pesticides?

A

reduces pest population instantly
can kill the whole population of pests

29
Q

what’s the disadvantages of pesticides?

A

cost (need for regular application)
not specific will kill predaceous insects and pollinating insects in addition to the pests

30
Q

what’s the advantages of biological control?

A

organism only introduced once as it will reproduce
only one cost for the initial introduction
pest specific- only kill the pests
pest will not become resistant
no effect on other animals in the food chain

31
Q

what’s the disadvantages of biological control?

A

takes time to reduce pest population
not all population killed
expensive if repopulating is required

32
Q

how is yeast and anaerobic respiration used?

A

anaerobic respiration in yeast is used during beer brewing and bread making:

glucose > ethanol + carbon dioxide

33
Q

how is bread making relevant?

A

bubbles of carbon dioxide gas expand the dough and help the bread rise
high temp used in bread making means the ethanol does not remain in the bread after cooking has finished

34
Q

what are two ways you can test for the presence of carbon dioxide:

A

limewater turns cloudy white (milky)
hydrogen carbonate indicator changes from orange to yellow

35
Q

how to test anaerobic respiration in yeast:

A
  1. dissolve sugar in previously boiled water
  2. add yeast and mix to form a suspension and pour into a boiling tube
  3. add a layer of vegetable oil (preventing oxygen entering while allowing co2 to escape insuring a anaerobic reaction)
  4. connect a delivery tube to a second boiling tube this time containing limewater or hydrogen carbonate indicator

condition that can be controlled:
temperature, concentration of sugar, type of sugar

36
Q

what are industrial fermenters?

A

used to grow microorganisms on an industrial scale

37
Q

industrial fermenters:
cooling jacket

A

removes heat energy stopping fermenter overheating and enzymes denaturing

38
Q

industrial fermenters:
air filters

A

filters air coming in, maintaining sterile conditions

39
Q

industrial fermenters:
stirrers

A

keep the broth well stirred oxygenates all parts of the fermenter and prevent microorganisms settling

40
Q

industrial fermenters:
growth medium

A

contains all necessary glucose and amino acids for microorganism growth

41
Q

industrial fermenters:
super heated steam

A

applied before fermenter is used killing unwanted microorganisms leaving only water will no other residue

42
Q

what bacterium is used to make yogurt?

A

lactobacillus bulgaricus

43
Q

how is yogurt produced?

A

milk is heated to kill bacteria
after it is cooled lactobacillus is added and mixture is maintained at 46 degrees
ensuring the bacteria’s enzymes do not denature
lactobacillus respires anaerobically producing lactic acid - lowering ph and acting as a preservative
- acid also coagulates the milk protein giving yogurt the texture and flavour

44
Q

what do farmers feed fish?

A

high lipid and protein food to promote rapid growth as well as regular feeding with small amounts so most get eaten

45
Q

what are the two negatives of putting serval species of fish in one pond?

A
  • INTERSPECIFIC COMPETITION different species will complete for food and some species may be wiped out
  • PREDATION carnivorous species will prey on other fish

solution: place different species in different ponds, tanks use nets to separate species and wild / farmed populations
(placing a cover over fish protects from birds)

46
Q

what happens when you put too many individuals in one pond?

A
  • INFRASPECIFIC COMPETITION larger individuals will out compete smaller individuals for food or larger individuals may prey on smaller individuals
  • INFECTIOUS DISEASES parasites and pathogens spread quickly if the fish are close together
47
Q

how do fish farms affect the environment?

A
  • fish may escape and out complete or interbreed with local species reducing biodiversity and upsetting the local ecosystem
  • parasites or pathogens can be introduced into ecosystems by farmed fish
  • excess feed and waste from fish can cause eutrophication and a reduction in oxygen and concentration in the water
48
Q

what is biodiversity?

A

the measure of how many different species live in an ecosystem

49
Q

how can you measure biodiversity?

A

find a 10m by 10m area
use random sampling - random number generator to find coordinates
using a quadrant record the number of species/number of different species in the quadrant
repeat 20 times
find average
times average by area

50
Q

what is abiotic?

A

non-living factor - temperature, light intensity

51
Q

what is biotic?

A

living factor - trampling

52
Q

how does deforestation affect biodiversity?

A

destroys habitats of organisms
causing extinctions
reducing biodiversity

53
Q

how does deforestation affect the carbon cycle and global warming?

A

during photosynthesis, carbon dioxide is taken into plants becoming a carbon sink
if deforestation occurs less plants to store carbon and carbon levels in atmosphere will increase
oxygen levels will decrease as less photosynthesis
trees may be burned release carbon dioxide back into atmosphere

54
Q

how does deforestation affect leaching?

A

water is normally absorbed by the soil however deforestation means water is no longer taken up by plants and runs into rivers and lakes
mineral ions that are in soil will dissolve into water that goes into local water sources
1. mineral ions removed from the soil
2. leads to problems like eutrophication

55
Q

how does deforestation affect soil erosion?

A

water running off areas may carry away some of the topsoil, causing erosion
topsoil - contains most fertile, mineral rich ions

56
Q

how does deforestation affect evapotranspiration?

A

transpiration cycle is broken by deforestation
lead to droughts

57
Q

how does sulphur dioxide pollute?

A

sulphur dioxide (as well as nitrogen monoxide and nitrogen dioxide) is released into the atmosphere from cars and factories
reacts with atmospheric water to form sulphuric acid
this acid dissolves limestone buildings
decreases the ph of rivers
catastrophic effect on enzymes of organisms - results in death of fish and other animals
kills trees

58
Q

what has an increasing human population resulted in?

A

an increased pollution
more fossil fuels being burnt for heat and power
movement and use of transport
higher levels of industry for houses and goods

59
Q

how does carbon monoxide pollute?

A

if substances containing carbon are burned in a limited supply of oxygen carbon monoxide is formed
binds with haemoglobin instead of oxygen causing a person to loose consciousness and die due to reduced aerobic respiration

60
Q

how can fertilizers cause eutrophication?

A

fertilizers contain nitrate and phosphates which are very soluble in water
can be washed out of the soil into rivers called leaching

61
Q

what are the effects of leached nitrates?

A

EUTROPHICATION
- nitrates absorbed by algae in water
- multiply rapidly and covers the top surface of water causing algal bloom
- blocking out sunlight for other plants in lake
- meaning they are unable to photosynthesis so they die
- dead stuff is good source of food for bacteria
- the bacteria respire and use up oxygen
- decreasing oxygen levels and resulting in death of organisms in water

62
Q

how can water be polluted by sewage?

A

sewage may enter water supply
- sewage provides a good source of food for bacteria
- bacteria multiply rapidly
- bacteria respire using up oxygen
- decrease level of oxygen resulting in the death of other organisms in water, fish as they can’t aerobically respire

gsce biology (28 decks)

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