Bio Topic 4; Making Use of Biodiversity

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Give 4 positive properties of plant fibres.
Very good tensile strength. Good heat, sound and electrical insulating properties. Products can be disposed of by burning & energy simultaneously produced. Fibres can biodegrade under right circumstances.
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Give 1 disadvantage of plant fibres.
Can't hold their shape under changing moisture conditions.
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How are fibres extracted from plants?
To obtain the fibres the plant must be taken apart which can either be done by mechanically pulling out the fibres or dissolving the surrounding tissue.
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How is it possible to obtain the plant fibres by dissolving the surrounding tissue without damaging the plant fibres themselves?
Because the cellulose and especially the cellulose combined with login is very resistant to chemical and enzyme digression while the polysaccharides holding the fibres tog. are easily dissolved.
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What chemical is needed to produce fibre pulp from trees?
Caustic Alkali
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What does the process called 'retting' entail?
Stems are piled up in heaps allowing bacteria and fungi to dissolve the tissue surrounding the plant fibres.
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Give an example of a biocomposite.
Rapeseed fibres mixed with plastic: form a material stronger than plastic by itself.
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What are the benefits of biocomposites?
They're renewable an can be safer and easier to handle than composites containing artificial fibres.
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How do bacteria reproduce?
Through binary fission; circular DNA replicated & new cell contents are synthesised before a new cell wall divided the cell into 2 equal parts.
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What are the ideal conditions for a bacteria population to grow exponentially ?
1. Sufficient nutrients 2. Optimum temp 3. Optimum pH 4.No build up of toxins 5. Oxygen present if bacteria respires aerobically
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Why when graphing bacterial population growth is the log of the population used as the y-axis label?
Because it allows a range of values from low to high to be placed on the same graph.
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Bacterial growth: What is the Lag Phase?
Cells are adjusting to the new environment (eg. synthesising enzymes)
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Bacterial growth: What is the Exponential Phase?
Cells are dividing exponentially at the fastest rate possible for the conditions.
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Bacterial growth: What is the Stationary Phase?
Growth is limited by lack of food, build up of toxins and change of pH.
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Bacterial growth: What is the Death Phase?
The number of cell deaths is greater than the number of cell's formed.
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Name the steps in testing a new drug.
Pre-clinical testing, Clinical trials; phase 1, 2 and 3 and then after licensing.
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Outline the stage of preclinical testing.
Animal & lab studies done on isolated cells and tissue cultures to determine whether compound is effective against target disease.
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Outline the stage of clinical trials- phase 1
Small group of volunteers are given different dosages.Trial confirms if compound being absorbed, distributed, metabolised & excited as predicted by lab tests. Effects of different doses observed.
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Outline the stage of clinical trials- phase 2
Larger group of volunteers with the disease is spilt into 2. 1 group given drug under investigation and other given a placebo. Neither patients nor doctors know who's getting what. If drug is deemed effective it can be licensed and sold.
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What is a double-blind randomised controlled test?
Group of volunteer patients split into 2. 1 group receives drug, other receives placebo. Neither doctors nor patients know who's getting what.
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How is a drug deemed effective by the 3rd phase of a clinical trial?
If the group of volunteer patients given the drug show greater improvements than the group given the placebo the drug is deemed effective.
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What occurs during the after-licensing stage?
Trials continue to collect data on effectiveness and safety of the drug as time goes on.
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Why are seeds adapted?
To protect the embryo, aid dispersal and provide nutrition for the new plant.
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Why is starch easy to extract from plants?
B/c the starch is in granules which can't dissolve in water but can be washed out.
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What is gelatinisation?
When starch is heated in h2o and suddenly swells, absorbing the h20 and thickening the liquid.
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What are some uses of starch's gelatinous properties?
The basis of custard and wallpaper paste, also used in cloth treatment to stiffen fabric.
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How are starch molecules made super absorbent?
They are chemically cross-linked before being gelatinised so particles are formed which can be dried. When rehydrates the particles can take up large amounts of water.
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What conditions are needed to male starch foam?
Very high temp. and high pressure then sudden release in pressure causing steam and starch to puff into expanded structure.
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What are the benefits of vegetable oil over petroleum diesel?
Produces less sulphur dioxide and carbon dioxide.
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Give 3 reasons why oil-based plastics are not sustainable.
1. Burning fossil fuels= net increase in CO2 concentration 2. Non-renewable 3. Plastics generate non-biodegradable waste.
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Vegetable oil fuel also releases CO2, how is it better than fossil fuels in this aspect?
When burning vegetable oil, the CO2 released is approx. the same quantity as the CO2 used up by the plants grown for the fuel = no net change in CO2 concentration. Fossil fuels release CO2 stores built up over long periods of time.
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What else must be taken into account when considering the sustainability of a plant product?
Th source of the plant product, the energy and pollution created and used during production and transportation of the product.
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Give 2 negative consequences of biodegradable plastic.
Most bacteria involved in degradation requires oxygen so packing buried deep in landfill can't degrade. When packaging placed near surface of landfill and degrades, methane is sometimes generated.
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Other cards in this set

Card 2

Front

Give 1 disadvantage of plant fibres.

Back

Can't hold their shape under changing moisture conditions.

Card 3

Front

How are fibres extracted from plants?

Back

Preview of the front of card 3

Card 4

Front

How is it possible to obtain the plant fibres by dissolving the surrounding tissue without damaging the plant fibres themselves?

Back

Preview of the front of card 4

Card 5

Front

What chemical is needed to produce fibre pulp from trees?

Back

Preview of the front of card 5
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