5. use of biological resources. Flashcards
Describe the effects on crop yield with increased carbon dioxide and increased temperature in glasshouses
Glass houses and polythene tunnels increase the heat in the environment that crops are growing in. Reactions happen faster when there is more heat, for example photosynthesis. Given photosynthesis produces energy that the plant needs to grow, if there is more heat there is more growth and so higher yield.
Carbon dioxide is a reactant in photosynthesis. If there is a more than enough carbon dioxide, then every plant will be able to photosynthesise as best as it can. The more photosynthesis the more glucose, the more glucose the more energy, the more energy the more growth. Hence crop yield is increased.
describe how glasshouses and polythene tunnels can be used to increase the yield of certain crops
In glasshouses and polythene tunnels conditions can be controlled. This control means that all the limiting factors for plant growth can be set to the optimum conditions; this will result in more growth, so higher yield.
How is fertiliser used to increase crop yield?
Fertilisers contain minerals that plants require to grow; most of them are called NPK fertilisers, this means they contain nitrates, phosphates and potassium.
Nitrates are needed to make proteins- proteins are what plant cells are made of. If there is a lot of nitrate in the soil then plants have the ability to grow as much as they can.
Phosphates are involved in respiration and growth- both things are needed to sustain a plant.
Potassium must be present for enzymes to work- with out it the plant wouldn’t be able to carry out reactions and so would die or have very limited growth.
What are the reasons for pest control?
What are the advantages and disadvantages of using pesticides and biological control with crop plants?
Pests can eat crops or damage them so they can’t be sold.
Pesticides (used to kill pests that reduce crop yield) :
Advantages-
The assure that crops won’t be damaged. Fast and accurate to apply. Instant results.
Disadvantages-
They can harm other wildlife.
Killing the pest may affect biodiversity.
Pesticides can leech into the soil and possibly pollute rivers or surrounding habitats.
Pests can become immune.
Biological control (introducing a predator into the environment with the crops to kill the pests):
Advantages-
Cheep. Self regulating.
Disadvantages-
The predator may enter the wild and effect the biodiversity.
What is the role of yeast in the production of beer?
Yeast converts sugar to ethanol (alcohol) and CO2 when it respires anaerobically.
What is the role of bacteria (Lactobacillus) in the production of yoghurt?
When Lactobacillus respire anaerobically, they make lactic acid: this acid clumps milk proteins together making yoghurt.
Fish farming: What are the methods which are used to farm large numbers of fish to provide a source of protein?
maintenance of water quality control of intraspecific and interspecific predation control of disease removal of waste products quality and frequency of feeding use of selective breeding
Fish are a source of protein in many diets, humans consume a lot of fish for this reason. Fish farms are used to supply fish because: the fish’s food safety standard is monitored; fresh water fish are declining; the deman for fish is increasing.
Fresh water fish may have come into contact with unclean water; containing sewage, waste, chemicals. In fish farming the water is filtered to make sure the fish don’t come into contact with anything it would be unsafe to digest. Also if the water is cleaned regularly the spread of disease is minimised and the oxygen levels are high enough to maintain the respiration of the fish.
Intraspecific predation is the fish being bred eating each other, this can be stopped by: separating fish of different ages; separating fish of different genders; feeding fish regularly; giving fish adequate room.
Interspecific predation is the farmed fish being prayed on by other species, this can be prevented by: fencing the area the fish are in; putting nets around the area the fish are in; keeping the fish in inside tanks.
To minimise spread of disease, the water the fish are in should be changed regularly and their surroundings sterilised often. Also if small amounts of fish are kept together then disease can only contaminate a few fish.
Waste can be removed by changing the water in a tank, or changing the nets and location of fish kept outside.
Fish need to be fed often in small amounts, this is so they don’t starve but they wont be able to over eat. It is important to feed fish food with nutrients in for growth.
Selective breeding can ensure that farmers produce fish with desired characteristics by letting only the fish with the right characteristics breed and pass on the gene.
How can plants with desired characteristics be developed by selective breeding?
Farmers can breed plants selectively choosing plants with characteristics they desire (eg colour, size of fruit) to pollinate.
How can animals be developed with desired characteristics?
Selective breeding.
Farmers can choose to make sure animals with characteristics they desire reproduce, their offspring will inherit the genes of the characteristic.
describe a simple experiment to investigate carbon dioxide production by yeast, in different conditions
Have a test tube of yeast in glucose solution. Put a layer of oil on top if you want the yeast to respire anaerobically (as it will prevent oxygen entering the solution.)
But the test tube in a water bath, heat the water to vary the temperature.
Collect gas coming off in a tube then: count the bubbles; use downwards displacement.
How can large amounts of human insulin be manufactured?
Large amounts of human insulin can be manufactured from genetically modified bacteria that are grown in a fermenter.
The gene that causes human insulin production is taken from a cell and put into a bacteria’s DNA. This bacteria is then put into a fermenter where the conditions are optimum for it to replicate many times. These bacteria then produce human insulin which can be harvested and given to humans with diabetes.
evaluate the potential for using genetically modified plants to improve food production
Genetically modified plants are ones with desired characteristics which are meant to enhance a crop.
They may have DNA which gives them more nutritional value: like golden rice which is rice with carotene in. This will benefit a population which eats a lot of rice by giving them a better diet.
Plants may also have DNA which makes them more resistant: for example genetically modified soya plants. This means that a broad spectrum herbicide that kills many different types of plant can be spread on the crops to kill weeds; where as before many different types of herbicides would have to be spread to avoid killing the crop (time consuming/ expensive.)
Although GM plants appear to be only of benefit, there are people who claim side effects observed in lab animals such as: sterility; infant mortality; allergies; stunted growth. Another disadvantage would be that a broad spectrum herbicide that can be spread on GM crops will kill many plants in the wild not just the weeds threatening the crops.
What does the term ‘transgenic’ mean?
transgenic material is genetic material that is taken from one species and put into another.
The transfer of genetic material from one species to a different species.
describe the process of micropropagation (tissue culture) in which small pieces of plants (explants) are grown in vitro using nutrient media
Plant clippings are taken and placed in a sterile growth medium.
Roots (and shoots) will develop from the clipping making a whole new plant.
The plant will then be transferred into compost and grown as a normal plant.
The plant is a clone of the one is was taken from because it has the same DNA. This means that there will be no variation, so you can have the same plant every time.
How can micropropagation be used to produce commercial quantities of identical plants (clones) with desirable characteristics?
In micropropagation, plant clippings are taken and put in a growth medium. They will develop into a new plant with the same DNA. This means that every plant made from the clippings of one plant will be clones with exactly the same characteristics. If many clippings are taken then you will have many clones.
