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biology biological resource (food production (microorganism (Industrial…
biology biological resource
food production
intensive farming
crops
Increasing Crop Yield
Glasshouses
Lighting, heating and higher carbon dioxide levels in glasshouses increase the rate of photosynthesis that is possible.
A high rate of photosynthesis means that crops grow faster and the total yield is bigger.
Polythene tunnels
Polythene tunnels are cheaper to construct than glasshouses.
Like glasshouses, farmers can use them to increase temperature, light intensity and carbon dioxide levels to increase photosynthesis and crop yield.
mineral ions
nitrate
Nitrates are needed for the production and synthesis (creation) of proteins.
Without proteins, plants cannot grow. This means that a nitrate deficiency causes stunted growth.
phosphates
Phosphates are needed to make DNA and cell membranes.
Phosphate deficiency affects the growth of roots, so plants have short, stunted roots.
potassium
Potassium is needed to make the enzymes needed for respiration and photosynthesis.
Potassium deficiency causes yellowing of a plant's leaves.
NPK fertilisers
NPK fertilisers contain nitrogen, phosphate and potassium.
They can be added to plants to prevent disease caused by mineral deficiency and promote healthy growth.
Pest Control & Fish Farming
pest control
pesticide
notes
Pesticides are chemicals that can be sprayed onto crops to kill insect pests.
However these chemicals often contain heavy metals that build-up in food chains. They often reach the top apex predators at deadly levels.
Biological control
biological control
notes
Biological control is an alternative method to using pesticides to reduce the impact of pests on crop yield.
A species that is a predator of the pest is introduced.
For example, ladybirds are sometimes introduced by farmers into fields or glasshouses to prey on whitefly pests.
Biological control must be monitored very closely, because introducing a species into a non-native habitat risks it becoming an invasive species.
methods
pesticides and biological control are two methods of reducing the impact of insect pests on crop yield.
pesticides are often very effective and can easily be applied to large areas of land. however, they have a negative effect on the environment
pesticide problems
pesticides are often not specific, so it will effect many animals not just the specific pest. they are often toxic, these toxic chemicals go up the food chain
biological control involves introducing a predator of an insect pest. the predator is often specific to one type of pest. its often slower that using a pesticide, but avoids putting chemicals into the food chain. it also has risks
biological control risks
there is a risk that introducing a non-native species into a habitat it will result in it becoming an invasive species since it has no natural predators
fish farming
disease
Fish parasites (such as sea lice) and diseases can easily spread through fish farms, because large numbers of fish are kept in very close proximity.
Often antibiotics are added to feed.
feeding
Fish are fed to maximise growth, size and total yield, whilst minimising cost and waste.
Feed is often high in protein to maximise growth.
predication
notes
Interspecific predation involves other species preying on farmed fish.
Nets keep out most aquatic predators from off-shore farms, and seabirds are kept out by netting across the top of farms.
Intraspecific predation involves the farmed fish eating each other.
This can be prevented by feeding the fish the right amount, and by not keeping them in conditions that are too cramped.
water quality
Fish farms in open seas receive fresh seawater with the movement of the tide, but water quality in fully enclosed fish farms must be tested regularly.
It is important that oxygen levels in the water are high, and the nitrogenous waste produced by fish is removed.
why
protien
omega 3
good for nerve develpment
microorganism
yeast
notes
In yeast cells, glucose is converted into ethanol and carbon dioxide.
Glucose → ethanol + carbon dioxide
This is called fermentation. The carbon dioxide produced causes the size of bread dough to increase while it is ‘proving’ during bread making.
bacteria
notes
A type of bacteria called Lactobacillus respire a sugar called lactose in milk to produce lactic acid.
Lactose → lactic acid
This lactic acid turns the milk into yoghurt, giving it a sour taste and thicker texture.
factors that effect the growth of microorganisms
temperature
notes
Growth rates are generally highest in warm temperatures.
Keeping food in the fridge or freezer slows that rate at which microorganisms divide and respire.
When bread is 'proved' it is kept warm so that the yeast respire quickly, producing carbon dioxide to make the bread rise.
moisture availability
Microorganism growth is generally fastest in moist conditions.
Industrial Fermentation
optimum pH
oxygenated
Aseptic conditions
The growth of other microorganisms would create competition for the desired microorganisms.
Dangerous microorganisms could also grow very easily in these conditions.
Plenty of nutrients
Agitated
Stirring paddles keep the contents of the fermenters moving to mix in oxygen and nutrients.
Optimum temperature
Depending on the microorganism, the fermenter may have to be heated, or cooled using a 'cooling jacket' of cold water.
selective breading
Promoting desirable characteristics
Humans have done this in farming for thousands of years (with both crops and animals) to promote the genetic characteristics that we view as desirable.
genetic engineering
genetic modification
cloning
Micropropagation
notes
Micropropagation (also called tissue culture) involves growing genetically identical cells in a lab under sterile conditions (without contamination from microorganisms).
First, a tissue sample is taken from a plant.
Then the cells are sterilised.
The sample is treated with hormones to trigger cell division, and grown on an agar plate (plant food in jelly form).
A ball of cells called a callus forms, and more hormones are added to cause roots and stems to grow.
The plants can now be planted into soil.
uses
transgenic animals
Transgenic animals that have had human genes inserted into their genomes can be cloned in large numbers to produce human proteins.
Transgenic animals can produce human antibodies for vaccines.
plants
notes
We can produce lots of genetically identical plants quickly from tissue culture cells.
We can produce these plants any time of year in a lab.
We can introduce genetic modifications quickly into a large number of plants, after modifying only a few plants.
We can increase the population numbers of rare plant species.
artifical animal cloning
Somatic cell nuclear transfer (SCNT)
notes
Somatic cell nuclear transfer (SCNT) was the method used to make Dolly the sheep.
SCNT involves the transfer of genetic material from the individual to be cloned into an enucleated egg cell, which is then implanted into a surrogate mother.
1) Egg enucleation
2) Transfer nucleus from somatic cell
3) Apply electric shock
4) Implant into surrogate
prosess
1) Egg enucleation
An unfertilized egg cell has its nucleus removed.
2) Transfer nucleus from somatic cell
The nucleus from the individual to be cloned is removed from a somatic (body) cell and transferred into the enucleated egg cell.
3) Apply electric shock
An electric shock is applied to the egg cell to stimulate cell division.
4) Implant into surrogate
Once the embryo has grown into a larger mass of cells, it is implanted into a surrogate mother.The embryo (a clone of the original somatic cell) will continue to develop in the womb of the surrogate.
