Harnessing Biology Flashcards
What is selective breeding?
adapting an animals biological characteristics during breeding
Why does selective breeding happen?
to create animals with desired characteristics
How does selective breeding work?
-choose desired feature
-breed organism with that feature
-only select offspring with desired feature
-repeat
What is the aim of selectively breeding crops?
-give higher yields
-resistant to certain diseases
-resistant to pests
-better balance of nutrients
What features of animals are selectively bred?
-produce more meat, milk, eggs
-produce more/ better quality fur
-produce more offspring
-increased resistance to diseases and parasites
What factors do farmers attempt to control to maximise crop yield?
-light intensity
-CO2 conc
-temperature
What features of a greenhouse are useful for farmers?
-artificial heating
-artificial lighting
-artificial CO2 in air
-regular watering
Greenhouses and polythene tunnels provide enhanced…
conditions for plants to grow
GREENHOUSES: Why is it made out of glass?
-transparent
-allows natural light for photosynthesis
GREENHOUSES: Why is it a benefit that they can be heated easily?
increases enzyme activity
GREENHOUSES: What is the benefit of burning fossil fuels as a heating method?
-conc of CO2 and water vapour increase
-both factors needed for photosynthesis
-also reduces water loss from plant through transpiration
5 ways to increase crop yield
- use of fertilisers
- leguminous crops
- ploughing fields
- controlling soil pH
- controlling CO2, light + heat
What do fertilisers provide for crops?
elements to grow - e.g. nitrates for proteins, magnesium for chlorophyll
What are organic fertilisers?
made from faces of farm animals (manure) mixed with straw
What are inorganic fertilisers?
inorganic compounds, such as potassium nitrates or ammonium nitrates in specific amounts for optimum yield production
What are ADVANTAGES of organic fertilisers?
-improves soil structure
-greater range of minerals
-less cost for farmer
What are the ADVANTAGES of inorganic fertilisers?
-mineral ions release immediately (FAST ACTING)
-contents known
-easy to apply
What are the DISADVANTAGES of organic fertilisers?
-slow acting
-may contain pests
-bulkier, more difficult to apply
What are the DISADVANTAGES of inorganic fertilisers?
-can lead to eutrophication (as fertiliser is soluble)
-requires regular reapplication
What do leguminous crops have in their root nodules?
nitrogen-fixing bacteria
How do leguminous crops increase crop yield?
-converts nitrogen gas into ammonium
-releases ammonium into soil
What are pests?
organisms that reduce the yield of crops or stock animals
2 ways to control pests
-use pesticides
-biological control (using another organism to reduce number of pests)
What pesticide kills plant pests?
herbicides
What pesticide kills insects?
insecticides
What pesticide kills fungi?
fungicides
What pesticide kills molluscs (slugs, snails)?
molluscicides
Pesticides help improve the…
yield from crops and livestock
Biological control NEVER…
eradicates a pest
Yeast respires…
anaerobically
What is the word equation for anaerobic respiration?
glucose —> ethanol + carbon dioxide
How does bread rise?
bubbles of carbon dioxide gas expand the dough
Does ethanol remain in bread after baking?
NO - due to high temperatures during bread making ethanol is evaporated
How can we investigate the rate of anaerobic respiration?
production of carbon dioxide
2 ways to test for carbon dioxide
-limewater (turns cloudy)
-hydrogen carbonate (yellow high conc, purple low conc)
PRACTICAL: Testing for rate of anaerobic respiration
-dissolve sugar in boiled water
-add yeast and mix
-add a layer of vegetable oil
-connect a delivery tube to a second boiling tube containing hydrogen carbonate indicator
PRACTICAL: What is the function of the layer of vegetable oil?
prevents oxygen entering (ensuring anaerobic respiration takes place)
What fungus produces the antibiotic penicillin?
Pencillium
Bacteria can be genetically engineered to produce…
human insulin
What bacteria is used in yoghurt prodcution?
Lactobacillus
Why is milk initially pasteurised?
to kill bacteria
What temperature is Lactobacillus maintained at?
46C
How does Lactobacillus respire and what are the products?
anaerobically to produce lactic acid
What temperature is yoghurt cooled to after production and why?
-5C
-helps preserve the yoghurt
What do farmers feed their fish?
-high lipid and protein food
-promotes rapid growth
How often do farmers feed their fish?
-regularly
-in small amounts
What is the problem of putting multiple species in one pond?
-interspecific competition (competition for food causing species to be wiped out)
What is Predation?
carnivorous species preying on other fish
How can Predation be solved?
place different species in different ponds, tanks etc
What is intraspecific competition?
when larger individuals out-compete small individuals for food/ larger individuals feed on smaller individuals
How do fish farms affect the environment?
-can reduce biodiversity (as some fish escape and out-compete others)
-parasites or pathogens can be introduced into ecosystems by farmed fish
-eutrophication + reduction in oxygen conc of water
Biodiversity def
the measure of how many different species live in an ecosystem
Effects of deforestation: Leaching
-mineral ions removed from soil
-can lead to eutrophication
Effects of deforestation: soil erosion
reduces chances of plants re-growing
Effects of deforestation: evapotranspiration
breaks cycle of transpiration - can lead to droughts
Fertilisers normally contain…
nitrates and phosphates
Fertilisers are extremely soluble in…
water
Eutrophication (step by step)
- fertilisers run off into rivers
- nitrates (in fertilisers) are absorbed by algae on top of river
- algal bloom (completely covers surface of water)
4.blocks sunlight for other plants in river - other plants die (as cannot photosynthesise)
- the algae dies
- bacteria multiplies and grows (feeding from dead plants)
- bacteria uses up oxygen in water
- decreases oxygen levels of water
- increases death of other organism (e.g. fish)
What is sewage?
undigested food material
Sewage provides a good source of food for…
bacteria to grow and multiply
What is beer made from?
barley
What does barley contain?
-starch
-starch is broken down into glucose
-glucose id fermented by yeast
How is wine made?
yeast is used to ferment sugars in grape juice
What is biotechnology?
using any organism to make products that are useful to humans
The inside of a fermenter tank must be…
sterilised
Why must the inside of a fermented tank be sterilised?
prevents product becoming contaminated by other microorganisms
What is an aseptic technique?
method to prevent contamination by unwanted organisms
Aseptic technique example
-filtering the air
-sterilising fermenter with steam
