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Use of Biological Resources
Increasing Crop Yields:
Photosynthesis:
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Keeping plants enclosed in a glasshouse makes it easier to keep them free from pests
and diseases
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Glasshouses trap the sun’s heat to keep the plant warm
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Farmers can also increase the level of carbon dioxide in glasshouses by using a
paraffin heater
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By increasing the temperature and CO2 concentration, as well as the amount of light
available, a farmer can increase the rate of photosynthesis for their plants
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Fertilisers:
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Plants need certain elements so they can make important compounds like proteins
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Sometimes these elements are missing from the soil because they’ve been used up
by previous crops
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This helps to increase the crop yield
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Pests that feed on crops are
killed using various methods of pest control
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Pesticides are a form of chemical pest control
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Some also harm other wildlife
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It means using other
organisms to reduce the numbers of pests, either by encouraging wild organisms or
adding new one
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Biological control can have a longer lasting effect than spraying pesticide, and be less
harmful to wildlife
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Getting the sugar out of the grain:
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ii
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The grains are the
dried in a kiln
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iii
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This is then sieved to remove the bits
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Hops are added to the mixture to give the beer its flavour
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Yeast is added and the mixture is incubated
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The fermenting vessels are designed to stop unwanted microorganisms and
air getting in
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The rising concentration of alcohol in the fermentation mixture due to
anaerobic respiration eventually starts to kill the yeast
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Different species of yeast can tolerate different levels of alcohol
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3
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Sometimes chemicals called clarifying agents
are added to remove particles and make it clear
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The beer is then pasteurised – heated to kill any yeast left in the beer and
completely stop fermentation
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But big breweries pasteurise it because there’s a risk
unpasteurised beer will spoil if it’s not stored in the right conditions after it’s sold
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Finally the beer is casked ready for sale
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Attach a bung with a tube to a second test tube of water
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Leave the tube to acclimatise, then count the bubbles produced in a time period
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Repeat with the water bath at different temperatures
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Usually to get maximum yield of products, good health and disease resistance,
temperament, speed, fertility, good mothering skills, attractive flowers or nice
smells
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From existing stock, choose the ones which have the best characteristics
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Breed them
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Select the best of the offspring, and breed them
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Continue
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Farmers can selectively breed sheep to increase the number of lambs born
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The characteristic of having large numbers of
offspring are passed on genetically
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Tall wheat plants have a good grain yield but are easily damaged by wind and rain
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These two types were cross-bred, and the best resulting wheat plants were
cross-bred again
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The cage also protects them from interspecific predation (being eaten by other
animals)
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The better the quality of food, the quicker and bigger the fish will
grow
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It’s important to keep younger fish separate from bigger fish and to provide regular
food – this makes sure that the big fish don’t eat the little ones
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Fish kept in cages are more prone to disease and parasites
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To avoid pollution from
chemical pesticides, biological pest control can be used instead
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Tanks:
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The water can be monitored to check the temperature, pH and oxygen level is OK
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The water can be removed and filtered to get rid of waste food and fish poo
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Genetic Engineering:
Enzymes:
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Restriction enzymes recognise sequences of DNA and cut the DNA at these points
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Two different bits of DNA stuck together are known as recombinant DNA
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There are two sorts –
plasmids and viruses
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o Viruses insert DNA into the organisms they infect
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The DNA you want to insert is cut out with a restriction enzyme
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Genetically Modified Plants:
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Crops can be genetically modified to increase food production in lots of different
ways – one it to make them resistant to insects, another is to make them resistant to
herbicides
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It also increases crop yield,
making more food
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This also can increase crop yield
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One is that
transplanted genes may get out into the environment
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Another
concern is that genetically modified crops could adversely affect food chains or
human health
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Cloning:
Micropropagation:
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Small pieces are taken
from the tips of the stems and side shoots of this plant
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The explants are sterilised to kill any microorganisms
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The explants are then grown in vitro – in a petri dish containing a nutrient medium
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It also contains growth
hormones
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Cells in the explants divide and grow into a small plant
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Transplanting a Nucleus:
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3
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5
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The nucleus of a sheep’s egg cell was removed, creating an enucleated cell
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This was a nucleus from a mature udder
cell of a different sheep
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The dividing cell was implanted into the uterus of another sheep to develop until it
was ready to be born
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Other
animals can be cloned using this method

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