learning outcomes for harnessing biology Flashcards
5.10 how can selective breeding develop plants with desired characteristics and why do we do it?
- plants are selectively bred by taking pollen from the anther of a plant with desirable qualities and transferring it directly to the stigma of another plant with the same desirable qualities. The offspring of these two plant with desirable characteristics, will also likely have the desirable characteristics. If then continue to breed the offspring with other plants with desirable characteristics.
- an example is yeast, the aim is to produce wheat with more grain and with shorter stronger stems
or show plants with increased resistance to parasites and disease
Why?
.to increase crop yield
.quicker growing
.pest resistance
.resistance to certain diseases
.make them hardier- can survive in harsher conditions, be productive for longer periods of the year
.have a better balance of nutrients in the crop
5.11 how can selective breeding develop animals with desired characteristics and why do we do it?
- humans have refined the process and now only allow breeding between only those individuals of a species which would produce offspring with desirable characteristics
- E.G which cattle to breed in order to produce cows with a higher milk yield
- which dogs to breed to produce a pedigree of dog of a specific type
or show animals with increased resistance to parasites and disease
.to produce more milk, eggs, meat
.produce more/better quality fur
.produce more offspring
.increase resistance to diseases and parasites
5.1 how can glasshouses and polythene tunnels be used to increase the yield of certain crops
- they created controlled environments for crops providing advantages such as temp regulation (useful to maintain optimum temperature for enzymes) , protection from pests and extended growing seasons, transparent walls (light for photosynthesis)
- you can use artificial heating, artificial lighting, have additional carbon dioxide in the air and provide regular watering in glasshouses. These enhance the growing conditions fir the plants meaning they will grow better
.transparent material - sufficient natural light for photosynthesis during summer. Additional lighting gives ‘longer day’ during winter
.greenhouse effect raises the temperature
.burning fossil fuels or wood also raises the temperature and releases CO2 and water vapour
.water vapour maintains moist conditions son reduces water loss by transpiration
These all increase the rate of photosynthesis and therefore increase the yield.
5.2 what are the effects on crop yield with increased carbon dioxide and increased temp in greenhouses
they will positively impact crop yield as hight co2 concentrations will enhance photosynthesis which leads to enhanced plant growth however this varies among different crops.
warmer temps can accelerate the growth cycle allows for more crop cycles per year, however it has drawbacks as excessive heat exposure will cause heat stress reducing potential yields.
5.3 how can the use of fertiliser increase crop yield
they provide essential nutrients to plants, these are nitrogen, phosphorous, potassium and magnesium
NITROGEN- is crucial for leaf and stem development, needed for production of amino acids and enzymes PHOSPHORUS- supports root growth and flowering, DNA
POTASSIUM- aids overall plant growth
MAGNESIUM- for production of chlorophyll needed for photosynthesis
5.4 what are the reasons for pest control and the advantages and disadvantages of using pesticides and biological control with crop plants
.we control pests as they can reduce crop yield therefore causing economic damage to the farmer
.PESTICIDES - herbicides - kill pant pests
Insecticides - kill insect pests
Fungicides - kill fungi pests
Molluscicides - kill molluscs (like slugs and snails)
Disadvantages - may damage ecosystems, pests can become resistant, slow to decompose, build up in tissues of organisms, build up and become more concentrated along food chains (bio accumulation), can kill other harmless insects, cost (need regular reapplication),
Advantages - rescues pest population instantly, can kill the whole population of pests
.BIOLOGICAL CONTROL - using other organisms to reduce the number of pests (using predator species), never eradicates a pest, only reduces them in number so farmers do not have economic damage
Advantages: organism only needs to be introduced once as it will reproduce, only one cost for initial introduction, pest specific (only kills the pest), pest will not become resistant, no effect on other animals in food chain
Disadvantages: takes time tor deuce pest population, not all pests killed, expensive if repopulating is required, difficult to contain introduced species, may become invasive
5.5 what is the role of yeast in the production of food including bread
.anaerobic respiration happens in some microorganisms such as yeast
.anaerobic respiration in yeast is used in bread making and beer brewing
.glucose —> ethanol + carbon dioxide
.C6H12O6–>2C2H5OH + 2CO2
.ethanol is the alcohol found in alcoholic drinks like beer and wine
.in bread making, bubbles of CO2 gas expand the dough and help the bread rise
.ethanol does not remain in the bread after cooking
5.6 describe the investigation on the role of anaerobic respiration by yeast in different conditions
.one way to investigate anaerobic respiration is to study the production of CO2 under different conditions
.in the presence of CO2: limewater = cloudy, hydrogen carbonate indicator = goes from orange to yellow
.method:
> set up apparatus (test tube with yeast in sugar solution with vegetable oil on top and bung with delivery tube to another test tube containing limewater)
> dissolve the sugar in boiled water
> add yeast and mix to form a suspension and pour into a boiling tube
> add a layer of vegetable oil (prevents oxygen entering the mixture meaning yeast is anaerobically respiring)
> connect a delivery tube to a second boiling tube, this time containing limewater or hydrogen carbonate indicator
Conditions to investigate: temperature, concentration of sugar, type of sugar
5.7 what is the role of bacteria (lactobacillus) in the production of yogurt
. Yoghurt is made using the bacterium LACTOBACILLUS BULGARICUS
. Milk is initially pasteurised (heated) to kill bacteria
.after it has cooled you add th bacterium
.maintain mixture at 46 degrees
.this ensurethe bacteria’s enzymes are not denatured
.lactobacillus respires anaerobically producing lactic acid.
.this lowers the pH, acting as a preservative
.the acid also coagulates the milk protein
.the yoghurt is further cooled to 5 degrees to preserve it
5.8 what it an industrial fermenter and why do you need to provide suitable conditions such as aseptic precaution, nutrients, optimum temp and pH, oxygenation and agitation, for the growth of microorganisms
.fermenters are used to grow microorganisms on and industrial scale
.cooling jacket: removes heat energy, stopping the fermenter overheating for and enzymes denaturing
.air filter: filters air coming in, maintaining sterile conditions
.stirrers: keep the broth well stirred to oxygenate all parts of the fermenter and prevent microorganisms settling
.growth medium: contains all necessary glucose and amino acids for microorganism growth
.super-heated steam:applied before the fermenter is used, killing unwanted micro-organisms. Leaves only water with no other residue
.aspetic techniques - methods to prevent contamination by unwanted microorganisms - sterilising to ensure that all microorganisms are killed, to prevent contamination and competition of microorganisms
.mixing - to ensure temp is constant throughout, to ensure all CO2 gets removed, to ensure O2 is encorporated
How do fish farms affect the environment?
.parasites or pathogens can be introduced to ecosystems by famed fish
.excess feed and waste can cause eutrophication and a reduction in oxygen concentrations in the water
5.9B what are the methods used to farm large numbers of fish to provide a source of protein, including maintaining water quality
.large scale fish farming
.water quality can be monitored
.temerature, oxygen levels,and chlorophyll ion the water are measured
. You can increase the amount of oxygen in the water by pumping air into the enclosure
.wtaer pumped through filters to remove waste products - waste contains nitrates - algal bloom so must be removed
5.9B what are the methods used to farm large numbers of fish to provide a source of protein, including controlling intraspecific and interspecific predation
.large scale fish farming
.fish of the same species may eat each other ( larger fish eat smaller fish of own species) - intrapecific predation
.competition between fish of different species - interspecific predation
.fish are usually sorted into tanks by size not species
5.9B what are the methods used to farm large numbers of fish to provide a source of protein, including controlling disease
.in large scale fish farming, parasites and pathogens spread quickly as the fish are all close together
.remove dead or infected fish quickly and add antibiotics to the water to kill bacteria
.add anti fungal or chemicals to kill parasites
5.9B what are the methods used to farm large numbers of fish to provide a source of protein, including removing waste products
.pump water through filters to remove waste products and prevent eutrophication
