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

Question 1

how to selectively breed:

Answer 1

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

Question 2

selective breeding:

Answer 2

produces different varieties however they are still the same species

Question 3

what is the key to success when selectively breeding?

Answer 3

not allowing individuals with undesirable features to breed

Question 4

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

Answer 4

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

Question 5

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

Answer 5

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

Question 6

how do greenhouses and polythene tunnels provide enhanced conditions?

Answer 6

• 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

Question 7

what do fertilisers provide?

Answer 7

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

Question 8

what are the two types of fertilisers?

Answer 8

organic
inorganic

Question 9

what is an organic fertiliser?

Answer 9

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

Question 10

what is an inorganic fertiliser?

Answer 10

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

Question 11

what are some advantages of organic fertilisers?

Answer 11

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

Question 12

what are some disadvantages of using organic fertiliser?

Answer 12

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

Question 13

what are some advantages of inorganic fertilisers?

Answer 13

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

Question 14

what are some disadvantages of inorganic fertilisers?

Answer 14

can lead to eutrophication as fertiliser is soluble
requires regular reapplication

Question 15

how else can you replace lost nitrates?

Answer 15

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

Question 16

what are pests?

Answer 16

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

causing economic damage

Question 17

how can pests be controlled?

Answer 17

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

Question 18

what are pesticides?

Answer 18

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

Question 19

examples of types of pesticides:

Answer 19

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

Question 20

how does biological control of pests work?

Answer 20

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

Question 21

what is the slight downside to biological control?

Answer 21

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

Question 22

what’s the advantages of using pesticides?

Answer 22

reduces pest population instantly
can kill the whole population of pests

Question 23

what’s the disadvantages of pesticides?

Answer 23

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

Question 24

what’s the advantages of biological control?

Answer 24

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

Question 25

what’s the disadvantages of biological control?

Answer 25

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

Question 26

how is yeast and anaerobic respiration used?

Answer 26

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

glucose > ethanol + carbon dioxide

Question 27

how is bread making relevant?

Answer 27

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

Question 28

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

Answer 28

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

Question 29

how to test anaerobic respiration in yeast:

Answer 29

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

Question 30

what are industrial fermenters?

Answer 30

used to grow microorganisms on an industrial scale

Question 31

industrial fermenters:
cooling jacket

Answer 31

removes heat energy stopping fermenter overheating and enzymes denaturing

Question 32

industrial fermenters:
air filters

Answer 32

filters air coming in, maintaining sterile conditions

Question 33

industrial fermenters:
stirrers

Answer 33

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

Question 34

industrial fermenters:
growth medium

Answer 34

contains all necessary glucose and amino acids for microorganism growth

Question 35

industrial fermenters:
super heated steam

Answer 35

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

Question 36

what bacterium is used to make yogurt?

Answer 36

lactobacillus bulgaricus

Question 37

how is yogurt produced?

Answer 37

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

Question 38

what is abiotic?

Answer 38

non-living factor - temperature, light intensity

Question 39

what is biotic?

Answer 39

living factor - trampling

Question 40

how does sulphur dioxide pollute?

Answer 40

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

Question 41

what has an increasing human population resulted in?

Answer 41

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

Question 42

how does carbon monoxide pollute?

Answer 42

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

Question 43

how can fertilizers cause eutrophication?

Answer 43

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

Question 44

what are the effects of leached nitrates?

Answer 44

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

Question 45

how can water be polluted by sewage?

Answer 45

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