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74 Cards in this Set
- Front
- Back
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What adaptations do bacteria have to live? |
-Flagellum for movement -Cell wall to maintain shape -DNA to control cell's activity and replication |
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What shapes can bacterial DNA be? |
spiral, rod, curved rod, spherical |
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How do bacteria reproduce? |
Asexually via binary fission |
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What is the aseptic technique? |
Getting bacteria to reproduce on an agar plate using sterilised equipment to prevent contamination from other microbes. |
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Why are bacteria so successful at surviving? |
-Can use huge range of energy sources -Live in a wide range of habitats -Some can make own food or take in organic nutrients |
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How many cells does yeast have? |
One |
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How can yeast's growth rate be altered? |
-Food availability -Temperature -pH -Removal of waste products -Doubles for every 10 degree celcius rise until optimum is reached |
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What's the structure of a virus? |
Small and made of a protein coat surrounding a strand of genetic material. |
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In what cells can viruses reproduce? |
Living cells- can be plant, bacteria or animal. |
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What does a virus do when it attacks? |
-Attach to host cell -Inject genetic material into said cell -Use cell to make components of new viruses -Cause cell to split open and die to release new viruses it's like in Alien when they burst out of ya chest |
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How is ______ spread and hows is it stopped? Salmonella Cholera Influenza |
Food- correct food hygiene Water- correct water treatment Air bourne droplets- correct tissue use and patient isolation |
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What are the four stages of an infectious disease? |
1. Microbe enters body 2. Incubation period 3. Production of toxins 4. Toxins cause symptoms like fever |
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What is the incubation period? |
The stage in an infectious disease in which a microbe reproduces many times without causing any symptoms. |
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Why might disease become rampant in areas that have just experienced natural disaster? |
-Sewage systems damaged meaning contaminated water supply -No electric so food in fridges decays -Large number of people migrate to small areas and facilities can't cope -Hospitals damaged and shortness of medical staff |
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Why do doctors study disease statistics? |
To see patterns and make predictions. |
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What is Louis Pasteur do? |
Helped prove germ theory by realising microbes from air can make our food go bad. |
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What did Joseph Lister do? |
Invented first antiseptic using carbolic acid to prevent wounds from becoming infected. |
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What did Sir Alexander Flemming do? |
Discovered first anti-biotic which was produced by fungus (penicillum) and is now used a lot (penicillin) |
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What do antiseptics do? |
Kill microbes and prevent their entry |
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What do antibiotics do? |
Kill microbes in the body |
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How does a bacterium strain become immune to antibiotics? |
Via a mutation which is then carried on through reproduction and becomes prominent by natural selection. |
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How do doctors try to prevent antibiotic resistance spreading? |
-prescribe antibiotics only when really necessary -advise patients to always finish treatment so partially resistant ones are killed |
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Explain the process of yoghurt making. |
1. Equipment sterilised 2. Milk pasteurised by heating to 78 degrees C 3. Cooled & incubated with a culture of bacteria 4. Sampling, adding flavours, colours, packaging |
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What bacteria is added to milk in yoghurt making and why? |
Lactobactillus Causes breakdown of lactose to lactic acid which makes the yoghurt taste more acidic |
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What's the word equation for fermentation? |
glucose --> ethanol + carbon dioxide |
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Explain the fermentation process. |
-Sugar extracted (grapes: wine, barley: beer) -Yeast added -Kept warm and allowed to ferment -Left to clarify then clear liquid is drawn off -Pasteurised and bottled |
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What process is used to make wine versus that of whiskey? |
Wine is made by fermentation but whiskey is stronger and thus made by distillation. |
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Why is distillation used for higher concentration alcohols? |
Alcohol concentration, when too high, kills yeast. So fermentation can't produce such high concentration. |
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What are biofuels made of? |
-Fast growing trees that are chopped then replanted -Sugar or waste material gets fermented with bacteria or yeast |
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Why have biofuels become so popular? |
-Alternative to fossil fuels that are running out -No net increase in greenhouse gas levels from them (carbon neutral) -Don't release particulates when burnt |
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What problems do mass use of biofuels cause? |
Large areas of land cleared and used for crops which takes habitats and could lead to it being not carbon neutral because the trees cut down to clear space can't take in carbon any more. |
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What does biogas contain? |
Mainly methane, some carbon dioxide, trace amounts of hydrogen, nitrogen and hydrogen sulphide. |
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How can biogas be produced? |
In a large scale digester where organic waste is constantly added and solids constantly removed. |
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What are the uses of biogas? |
-Burnt to generate electricity -Burnt to produce hot water and steam for heating systems -Used as vehicle fuel |
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At what temperature does biogas production slow? |
45 degrees C, above there enzymes denature |
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What percentage of methane in biogas is manageable and what is explosive? |
50% ok 10% explosive |
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What is gasohol? |
Alcohol mixed with petrol. Used mainly in Brazil. |
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What are the good things about gasohol? |
Good for places with lots of sugar cane but little oil Cheaper than importing oil |
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What is loam? |
A soil that contains a mixture of clay and sand as well as a large amount of partly decomposed animal and plant waste called humus. |
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How can humus content in soil be found? |
Burning off the humus using a bunsen burner |
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How can air content of soil be found? |
Seeing how much water is needed to fill the air spaces |
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How can water content be found in soil? |
Slowly heating the soil to evaporate the water |
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If a soil has larger particles, the air content and permeability is...? |
Higher |
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If a soil has larger amounts of humus it will often hold ___ water and air? |
More |
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Why is humus important in soil? |
-Decompose to release minerals -Increase air content of soil |
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Why are earthworms important to soil structure? |
-Bury organic material for decomposition by bacteria and fungi -Aerate and drain the soil -Mix up soil layers -Neutralise acid soil |
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Why is soil aeration important? |
Allow organisms to respire aerobically |
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Why is neutralising soil important? |
Plants won't grow if the pH is too low |
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Why is mixing up soil layers important? |
Dead material can be decomposed |
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Who first understood earthworms? |
Charles Darwin |
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What are the advantages of living in water? |
-No risk of water shortage or dehydration -Temp of water varies less than air -Helps provide support -Waste products easily disposed in water |
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Disadvantages of living in water? |
-Water content of body can vary and needs to be controlled -Water is denser than air + so resists movement |
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What happens in fresh water versus salt water? (think osmosis) |
Freshwater organisms take up too much water but salt-water lose too must |
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What's a contractile vacuole? |
Things in amoeba that can store excess water then fuse to the cell membrane to empty the water outside. |
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What factors affect phytoplankton and zooplankton distribution? |
-Light due to depth of water -Temperature at lower depths and in winter -Minerals are used up towards the end of summer |
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What do most deep-ocean food chains rely on? |
Marine snow or bacteria |
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What does sewage/fertiliser run-off cause? |
Eutrophication where algae grows quickly then dies and uses up all oxygen to be decomposed so animals and other plants die because they can't respire. |
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What 2 things can be detected with biological indicators? |
pH and oxygen |
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What problems do PCBs and DDT cause? |
They accumulate in food chains until they reach toxic levels. Happens to whales a lot. |
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How do biological washing powders work? |
Amylase digests carb stains like starch Lipase digests fat stains Protease digests protein satins After this, the stains are soluble and easily wash off |
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What are the optimum conditions for biological washing powders?
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Moderate temperatures Neutral pH |
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What breaks down sucrose? |
Sucrase (invertase) |
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What alternative to sucrose is used in food industries and why? |
Sucrose is broken down into glucose and fructose which are both much sweeter and thus less can be used to have the same taste. Lowers costs, eh. |
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How can we immobilise enzymes? |
-Mix with alginate -Drop into calcium chloride solution |
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Why are immobilised enzymes used? |
-Mixture won't be contaminated by enzyme -Can be used in continuous processing |
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What causes lactose intolerance? |
Cannot produce enzyme, lactase. This means bacteria in the gut just ferment the lactose causing diarrhoea and wind. |
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How is milk treated for the lactose-intolerant? |
-Immobilised lactase converts lactose into glucose and galactose -The glucose and galactose are then absorbed from the milk with no side effects |
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What's a transgenic organism? |
One that receives a new gene from another organism |
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What's the process of genetic engineering? |
-Identify and remove desired gene from A using restriction enzymes, this leaves unpaired bases (sticky ends)
-Cut open DNA from B -Insert gene from A into B's DNA -Make sure the gene works -Ligase joins DNA strands because the sticky ends on the cut section join by complimentary base pairings |
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How do we genetically engineer insulin? |
-Get human gene for insulin production -Cut open a loop of bacteria DNA (plasmid) -Insert insulin gene into bacteria DNA -Insert the bacteria DNA into a bacterium -Clone large quantities! |
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What are plasmids and where are they found? |
Loops of bacteria DNA used as vectors for genes. Found in the cytoplasm of bacteria. |
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How do you test to see if a bacterium has taken up the plasmid? |
Assaying technique. -Add genes that make the bacteria resistant to antibiotics -Bacteria then flooded with antibiotic by being grown on a nutrient agar with an antibiotic -Choose the ones that live lol like the hunger games |
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Why do people disagree with DNA fingerprints? |
They could be used to assess likelihood of certain diseases and thus be a reason to refuse insurance. |
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How does one produce a DNA fingerprint? |
-Extract DNA sample (like blood) -Fragmenting it using restriction enzymes -Separate fragments using electrophoresis -Make fragments visible with radioactive probe |
