Topic N - Man's use of biological resources Flashcards
How are glasshouses used to increase the yield of certain crops
- Crops free from pests and diseases
- Control water supply
- Artificial light = more time to photosynthesis
- Trap heat = keep plants warm ( heater used in winter)
- Increase level of CO2 - use paraffin heater
How do polythene tunnels increase crop yield
Large plastic sheet over crops
Keeps crops warm and contains humidity
What is the difference between glasshouses and polythene tunnels
Glass houses are more expensive than polythene tunnels because more variables can be controlled
How does increasing the temperature and CO2 and light effect crop yield
Increase rate of photosynthesis
Plants grow bigger + faster
Crop yields = higher
How does the use of fertiliser increase crop yield
Fertilisers replace missing minerals in the soil or provide more of them= increase crop yield
What 4 important minerals do plants require and why
Nitrogen
Phosphorus
Potassium
Magnisum
Because needed to make important compounds like proteins
What are the reasons for pest control
To kill pests that feed on crops = fewer plants are damaged or destroyed = increase in crop yield
Definition of pesticides
Group of chemicals that target pests
Definition of biological control
Alternative to using pesticides
Using other organisms to reduce the number of pests
By encouraging wild organisms or adding new ones ( predators )
What are 2 forms of pest control
Pesticides
Biological Control
What are the advantages of pesticides
Easy to control
Effective- kills the pest
Relatively cheap
What are disadvantages of pesticides
Poisonous to humans
Harm other wildlife
Not very specific
Requires constant labour ( each season )
Can contaminate food supply= effect food chain
Advantages of biological control
lasts longer no reapplication specific avoids bioaccumulation ( food chains ) no development of resistance
Disadvantages of biological control
New organisms = pest themselves
Undesired/ unknown effects
Less guarantee it will work
Expensive- maintenance + labour ( needs highly trained people )
PAPER 2
Why do people want to farm large numbers of fish
To provide protein
PAPER 2
What methods are used in fish farming to produce large amounts of fish
- Maintains water quality ( filter out watste)
- Protection from interspecific predation ( being eaten by other animals eg. Birds + seals)
- Controlling intraspecific predation ( organisms eat individuals of the same species) = separate small and large fish so small fish don’t get eaten
- Controlling quality and frequency of of feeding = maximise energy = bigger + quicker fish will grow
- Controlling disease
- Selective breeding = less aggressive + faster growing fish produced
what is yeast
a useful microorganism
what happens when yeast respires aerobically ( in presence of oxygen)
it breaks down sugar into CO2 and water
where is yeast used and how does it work
baking
mixed into the dough to create bubbles of CO2 that make dough rise
how does yeast work in the production of bread
- enzymes breakdown carbohydrates into sugars
- yeast uses sugars in aerobic respiration = produce CO2
- when oxygen runs out= anaerobic respiration (fermentation) = produce CO2 + ethanol (alcohol)
- CO2 produced = trapped in bubbles in the dough
- pockets of gas expand + dough rises
- dough baked= temperature kills yeast = stop fermenting + alcohol produced = boiled away
- yeast dies = bread stop rising – but pockets left in bread where CO2 was trapped
what is a fermenter ( in industry) and what are there purposes
a large container where useful microorganism are grown
to make the yield of products from the microorganisms can be as big as possible
what is a fermenter filled with
full of liquid culture medium in which microorganisms can grow and reproduce
what are the conditions inside a fermenter
conditions are kept at the optimum levels for growth= yield of products can be as big as possible
list the conditions controlled in a fermenter
- aseptic precautions ( sterilisation with superheated steam kills unwanted microbes)
- nutrients
- optimum temp + pH
- oxygenation
- agitation
what are aseptic precautions in a fermenter
vessels sterilised with super heated steam = kill unwanted microbes
why are aseptic precautions needed in a fermenter
increases product yield
microorganism aren’t competing with other organisms
product doesn’t get contaminated
why are nutrients needed in a fermenter
provided in the liquid culture medium
needed for growth
why is an optimum temp. needed in a fermenter
provided by water cool jacket
needed so doesn’t get to hot an so enzymes don’t denture
why is an optimum pH needed in a fermenter
needed for microorganisms enzymes to work efficiently
keeps rate of reaction and product yield as high as possible
why is an oxygenation needed in a fermenter
provided by pumping in sterile air
needed for respiration to provide energy for growth
what is agitation in fermenter
when microorganisms are kept in contact with fresh medium by paddles that circulate (agitate) the medium around the vessel
why is an agitation needed in a fermenter
needed so microorganisms can always access the nutrients need for growth = increases the product yield
what is selective breeding
develops plants and animals with desired characteristics
by taking the best plants or animals and breeding them together to get the best possible offspring
list some features why organism are selectively bread
maximum yield of meat, milk , grain
good health and disease resistant
speed, fertility, good mothing skills ( animals )
attractive flowers, nice smells
how can plants be genetically modified to improve food production
resistant to insects
resistant to herbicides ( chemicals that kill plants )
what are the benefits of making crops insect resistant
farmers don’t need to spray as many pesticides = wildlife that doesn’t eat crops = not harmed
increases crop yield = make more food
what are the benefits of making crops herbicide resistant
farmers can spray their crops to kills weeds without affecting crop itself
what are the concerns with genetically modifying crops
- transplanted genes may get out into environment = create super weeds
- could adversely affect food chains or even human health
why are some people totally against genetic engineering all together
worry that changing an organisms genes = create unforeseen problems= passed onto future generations
definition of transgenic
transfer of genetic material from one species to a different species
genes transferred from another species
(eg. insulin- restriction & ligase enzymes, recombinant DNA)
PAPER 2
describe the process of micropropagation (tissue culture ) in which explants are grown in vitro ( cloning plants )
- plant with desirable characteristics is selected to be cloned
- Explants ( small pieces ) are taken from tips of stem or side shoots = meristem ( stem cells = living growing tissue)
- explants sterilised= kill any microorganisms
- explants grown in vitro = placed petri dish containing nutrient medium ( contains nutrients + growth hormones = needed for explants to grow )
- cells in explant divide + grow into a small plant (further explants can be taken from small plants until enough are produced)
- small plants taken out of medium= planted in soil + put in glasshouses
- develop into plant genetically identical to original plant ( share same characteristics)
PAPER 2
what is micropopagation used for
to produce commercial quantities of genetically identical plants with desirable characteristics
PAPER 2
describe the stages in the production of cloned mammals ( use dolly the sheep as example )
- nucleus of sheeps egg cell = removed = enucleated cell ( cell without nucleus )
- diploid nucleus from a mature (udder) cell (of a different sheep) = inserted into enucleated cell
- cell = stimulated ( by electric shock) = start dividing by mitosis ( as if it was a normal fertilised egg) = develops into embryo
- dividing cell ( embryo ) = implanted in uterus of another sheep ( segregate mother ) to develop until it was ready to be born.
- result = dolly = clone of sheep that udder cell came from.
PAPER 2
how can cloned transgenic animals be used to produce human proteins
cows + sheep make protein naturally in their milk
by transferring human genes into the cells of theses animals = produce useful human proteins in milk
PAPER 2
what have transgenic chicken been engineered to produce
human proteins in egg white
PAPER 2
what can transgenic cows and sheep produce in their milk
can produce human antibodies = used in therapy for illnesses like arthritis, some types of cancer and multiple sclerosis
PAPER 2
what can be done to transgenic animals which is beneficial
can be cloned = useful genetic characteristics = passed on ( this doesn’t always happen with breeding)
PAPER 2
definition of clone
genetically identical organisms
