Flashcards in use of biological resources biology p2 Deck (50):
what is the yield?
how much of something is produced
-can be increased by growing crops in glasshouses of polythene tunnels
- these allow farmers to control:CO2 levels and temperature
-keeping them enclosed keeps them free of pests and diseases
-use artificial light
-trap the sun's heat and keep plants warm
-increase CO2 by using a paraffin heater- CO2 is a by-product
what happens when you increase CO2 levels?
-increased yield and increased rate of photosynthesis
what happens when you increase temperature?
increased yield and increased rate of reaction
why are fertilisers used?
-add nutrients to the soil(nitrogen, potassium and phosphates) to make proteins
-can be chemical or organic
-increase crop yield
what are pesticides?
-chemicals that are used to kill pests
- herbicides (kill plants)
- insecticides (kill insects)
why is biological control good and bad?
they are long lasting and can be less harmful to wildlife but introducing new wildlife can be a problem
why are pesticides bad?
poisonous to humans so be careful how much to put on food
they can harm other wildlife
what is biological control?
an alternative to pesticides. It means using other organisms to reduce the numbers of pests, by either encouraging wild organisms or adding new ones
what's an example of biological control?
pest: cane beetles
problem: eating sugarcane crops
solutions: introduce cane toads to eat the beetles
issues: toads become pests because they poison the native species that eat them
what are the advantages/disadvantages of pesticides ?
adv: chemicals kill most things, fast acting, many specialised types
disadv: kill things you don't want them to kill, can get into soil and waterways, expensive
what are the advantages/disadvantages of biological control?
adv: cheap, no chemicals used
disadv: introduced species can take over and become pests, slower process, less reliable
the use of living organisms to make useful chemicals and products or to perform an industrial task
how is yeast used to brew beer?
1)need to get the sugar out of the grain
- beer is made from grain (barley)
- the grains are allowed to germinate for a few days were starch is broken down into sugar by enzymes- grains are then dried in a kiln= malting
- the malted grain is then mashed up and water added to make a sugary solution with lots of bits in it- then sieved
-hops are added to give bitter flavour
2) yeast is added to mixture then its incubated. the yeast ferments the sugar into alcohol. the fermenting vessels are designed to stop unwanted microorganisms and air getting in
-the rising conc of alcohol in the mixture due to anaerobic respiration starts to kill the yeast. as the yeast dies, fermentation slows down
- different species of yeast can tolerate different levels of alcohol.
-some species can be used to produce strong beer with a high concentration of alcohol
3) the beer is drawn off through a tap. sometimes chemicals called CLARIFYING AGENTS are used to remove particles and make it clearer
4) the beer is then pasteurised- heated to kill any yeast left in the beer and stop fermentation
when does beer taste better?
if it's unpasteurised and aged in the right conditions but big breweries pasteurise it as there's a risk that unpasteurised beer will spoil if not left in the right conditions after its sold
why might some organisms be selectively bred?
1- maximum yield of meat, grain, milk
2- good health and disease resistance
3- temperament, speed, fertility, good mothering skills
4- plants have attractive flowers, nice smell
stages of selective breeding?
1) from existing stock, select the ones with the best characteristics
2) breed them with each other
3) select the best of the offspring and breed them together
4) continue this process over several generations, and the desirable trait gets stronger and stronger- better yields
what can selective breeding be useful for?3 things
1- increase the productivity of cows-selectively bred to produce offspring with e.g. high meat yield
2- increase the number of offspring in sheep- females who produce large numbers of offspring bred with rams whose mothers had large no. offspring
3- increase crop yield- get 2 desirable characteristics
tall wheat plants have good grain yield but easily damaged by wind and rain
dwarf wheat plants can resist wind and rain but have a lower grain yield
-both are cross-bred so new variety with the best characteristics- dwarf wheat plants which could resist bad weather and had a high grain yield
what do fish farms do?
rear fish in a controlled way that's designed to produce as many fish as possible
how are salmon fished in cages?
1) kept in cages in the sea to stop them using as much energy swimming about
2) the cage protects them from interspecific predation
3) the're fed a diet of food pellets that's carefully controlled to maximise the amount of energy they get. The better the quality of food, the quicker and bigger the fish will grow= good source of protein
4) young fish are reared in special tanks so as many survive as poss
5) younger fish kept separate from bigger fish, and to provide regular food-make sure the big fish don't eat the little ones. this is intraspecific predation
6) fish kept in cages are more prone to disease and parasites. One pest is sea lice, which can be treated with pesticides to kill them. To avoid pollution from chemical pesticides, biological pest control can be used instead: small fish called a wrasse eats the lice off the backs of the salmon
7) the fish can be selectively bred to produce less aggressive, faster-growing fish
how else are fish farmed?
in tanks or ponds where conditions can be controlled
- water is monitored to check the temp, pH and O2 levels
- control food supplied and give exactly the right sort
- the water can be removed and filtered to get rid of waste food and fish poo. this keeps the water clean for the fish and avoids pollution wherever the water ends up
what is the idea of genetic engineering?
to move useful genes from one organism's chromosomes into the cells of another
what do restriction enzymes do?
they recognise specific sequences of DNA and cut the DNA at these points
what do ligase enzymes do?
used to join two pieces of DNA together
what's known as recombinant DNA?
when two different bits of DNA are stuck together
what is a vector?
something that's used to transfer DNA into a cell, 2 types:
what are plasmids?
small, circular molecules of DNA that can be transferred between bacteria
how do viruses work as vectors?
they insert DNA into the organisms they infect
how does genetic engineering work?
1) the DNA you want to insert is cut out with a restriction enzyme. The vector DNA is then cut open using the same restriction enzyme
2) the vector DNA and the DNA you are inserting are mixed together with ligase enzymes
3) the ligases join the two pieces of DNA together to produce recombinant DNA
4) the recombinant DNA is inserted into other cells e.g. bacteria
5) these cells can now use the gene you inserted to make the protein you want
what can fermenters be used for?
to produce large quantities of genetically modified bacteria
what can improve food production?
genetically modified plants
how are genetically modified plants used?
-one is used to make them resistant to insects another to herbicides
what's the advantage of making crops insect-resistant?
farmers don't have to spray as many herbicides- so wildlife that doesn't eat the crop isn't harmed. Increases crop yield=more food
what's the advantage of making crops herbicide -resistant?
means farmers can spray their crops to kill weeds, without affecting the crop itself- increases crop yield
what are the concerns about genetically modified crops?
1- transplanted genes may get out into the environment e.g. a herbicide resistance gene may be picked up by weeds, creating a new 'superweed' variety
2- they could adversely affect food chains or human health
4- side effects are not yet known-passed onto future generations
what are the advantages of genetically modified crops?
- crops can grow in all directions
-can change the features of a crop
- natural pesticides
- extended growth periods
what is micropropagation? and what does it allow?
where plants can be cloned from existing plants - tissue culture
allows: plants to be cloned in large numbers
allows: for the cloning of plants with desirable features
how is a pant cloned?
1) small pieces- explants are taken from the tips of the stems and the side shoots of the plant
2) the explants are sterilised to kill any microorganisms
3) the explants are then grown in vitro- placed in a petri dish containing a nutrient medium.It has all the nutrients the explants need to grow and contains growth hormones
4) cells in the explants divide and grow into a small plant. if large quantities of plants are required, further explants can be taken from these small plants until enough produced
5) the small explants are taken out the medium and planted in soil in glasshouses- they'll develop into plants that are genetically identical to the original plant and so share the same characteristics
what are the advantages of micropropagation?
reproduce desired plants
make more plants of ones where there isn't many
can grow in all weather conditions
all plants are identical
why is micropropagation a bad thing?
- all plants the same so can all die if one gets sick
how is cloning done in a mammal?
1) cell removed from male or female who is being cloned
2) nucleus (DNA) removed from cell - creating an enucleated cell- no nucleus
3) egg cell removed from female donor and its nucleus is disposed of
4) nucleus of mammal being cloned is injected into the enucleated egg cell of the donor
5) the cell is stimulated- given an electric shock to start dividing to form an embryo by mitosis
6) embryo is implanted into the uterus of another female (surrogate)
7) offspring is identical to original organism
how is yoghurt produced?
yoghurt is basically fermented milk:
1-the equipment is sterilised to kill off any unwanted microorganisms
2- the milk is pasteurised (heated to 72 degrees Celsius for 15 s)- to kill any harmful microorganisms. The the milk is cooled
3- Lactobacillus bacteria are added, and the mixture is incubated(40 degrees Celsius) in a vessel called a fermenter
4- the bacteria ferment the lactose sugar in the milk to form lactic acid
5-lactic acid causes the milk to clot, and solidify into yoghurt
6- finally, flavours and colours are sometimes added and the yoghurt is packaged
what is fermentation?
when microorganisms break sugars down to release energy usually by anaerobic respiration
how are microorganisms grown and why are they useful?
grown in fermenters and the microorganisms can be used to make really useful stuff- penicillin or insulin
what is the fermenter full of?
liquid 'culture medium' in which microorganisms can grow and reproduce
how are the condition inside the fermentation vessel kept?
at optimum levels for growth so the yield of products from microorganisms can be as big as possible
describe how a fermenter works
1) nutrients needed by the microorganisms for growth are provided in the liquid culture medium
2) the pH is monitored and kept at the optimum level for the microorganisms' enzymes to work efficiently. This keeps the rate of reaction and product yield as high as possible
3) the temperature is monitored and kept at an optimum level. A WATER-COOLED jacket makes sure it doesn't get so hot that the enzymes denature
4)vessels are sterilised between uses with superheated steam that kills unwanted microbes. Having aseptic conditions increases the product yield because microorganisms aren't competing with other organisms. AND the product doesn't get contaminated
5) if the microorganisms need oxygen for respiration, it's added by pumping in sterile air. This increases the product yield because microorganisms can always respire to provide the energy for growth
6)microorganisms are kept in contact with fresh medium by paddles that circulate (agitate) the medium around the vessel. This increases the product yield because microorganisms can always access the nutrients needed for growth
what does transgenic mean?
means that the organisms contains genes transferred from another species
what are bacteria that contain the gene for human insulin?
what are the advantages of cloning?
1- animals that can produce medicines in their milk could be cloned.
2-Researchers have managed to transfer human genes that produce useful proteins into cheep and cows, e.g. human antibodies used in therapy for illnesses like arthritis, some types of cancer and multiple sclerosis
3-animals (pigs) that have suitable organs for organ transplantation into humans could be developed by genetic engineering and then cloned in the same way
4- benefit- useful genetic characteristics are always passed one which doesn't happen with breeding.
5- farmers don't have to wait until breeding season and infertile animals can be cloned