Biology B6 (OCR Gateway)

What does a flagellum do in bacterial cells?
Helps bacteria to move
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What does the cell wall do in bacterial cells?
Maintains the shape of bacteria and stops them bursting
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What does DNA do in bacterial cells?
Controls activities and reproduction in bacterial cells
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What are the four shapes of bacteria?
Spherical, rod, spiral and curved rods
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How do bacteria reproduce?
A type of asexual reproduction called binary fission
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What is meant by aseptic techniques?
Keeping unwanted microbes out when growing bacteria
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How can the growth rate of yeast be increased?
Controlling: food availability, temperature, pH and removing of waste products
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What do viruses consist of?
A protein coat surrounded by a strand of genetic material
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Where can viruses reproduce?
Only in other living cells
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What specific cells can viruses attack?
Plants, animals or bacteria
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How can diseases be spread?
Food, water, contact or airborne droplets
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What are the four stages of infection by a disease?
Entry into the body, rapid growth (incubation), production of toxins and appearance of symptoms
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Name four factors that can affect the spread of disease.
Damage to water and sewage supplies, damage to electricity supplies, displacement of people, disruption of health services
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Who formulated the germ theory of disease?
Louis Pasteur
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What did Joseph Lister develop?
Antiseptics which control disease
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What did Alexander Fleming discover?
Antibiotics which kill bacteria and fungi, but not viruses
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How are some bacteria becoming resistant to antibiotics?
Natural selection
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What are the five stages of yoghurt production?
Sterilisation of equipment, pasteurisation, incubation, sampling and adding colours/ flavours
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What do Lactobacillus bacteria do?
Convert lactose (milk sugar) into lactic acid
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What is fermentation?
Anaerobic respiration in yeast; sugars are converted into ethanol (alcohol) and carbon dioxide
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What is the balanced symbol equation for fermentation?
C6H12O6 ------> 2C2H5OH + 2CO2
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What are the main stages of making beer?
Extracting sugar from a source, adding yeast and keeping it warm, preventing entry of air/microbes, clarifying/clearing, drawing off the beer, pasteurising and bottling
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What is limited by fermentation?
The concentration of alcohol that can be produced
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How do different strains of yeast differ?
Can tolerate different concentrations of alcohol
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What is distillation used for?
Increasing the alcohol concentration in drinks
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How can biomass provide energy?
Burning fast growing trees, or via fermentation
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What are biofuels?
Alternatives to fossil fuels, which do not produce particulates or add to greenhouse gas levels
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What does biogas contain?
Mainly methane, some carbon dioxide, traces of hydrogen, nitrogen and hydrogen sulphide
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How does the amount of methane affect biogas?
Biogas containing more than 50% methane is burnable, but below 10% methane it is explosive
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What are an advantage and disadvantage of biogas?
A 'cleaner' fuel than petrol or diesel but contains less energy than natural gas
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What can biogas be used for?
Providing electricity, hot water, and steam for heating or to fuel cars
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What is gasohol?
A mixture of petrol and alcohol used in cars in countries like Brazil
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What is loam?
A soil with a mixture of sand and clay
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What is humus?
Mostly decomposed dead material in soil
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What happens when humus decomposes?
It releases minerals into the soil, and aerates the soil
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What does most life in soil need?
A supply of air and water
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What do earthworms do?
Bury organic material, which is decomposed by bacteria and fungi
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Name three functions of earthworms in soil.
Aerate and drain soil with their burrows, mix up layers of soil and neutralise acidic soil
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Who recognised the importance of earthworms in agriculture?
Charles Darwin
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What are the four major advantages of living in water?
No shortage of water/risk of dehydration, less temperature variation, support of the body, easy to dispose of waste
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What are the two disadvantages of living in water?
Regulating water content and resistance to movement
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What in water varies with seasons and depth of water?
Light, temperature and mineral content
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How can some food chains in oceans vary?
Some start with bacteria, not plants, and some rely on marine snow
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What are phytoplankton?
Microscopic plants
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What are zooplankton?
Microscopic animals
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What can sewage and fertiliser run off cause?
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What are biological indicators?
Species which are only able to survive at particular levels of oxygen or at particular pHs.
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What do biological washing powders contain?
Carbohydrases to digest carbohydrate stains, lipases to digest fatty stains and proteases to digest protein stains
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What is the optimum temperature for biological washing powders?
40 degrees C.
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How can sucrose sugar be broken down?
By the enzyme sucrase into the smaller, sweeter sugars glucose and galactose
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What does using sweeter sugars mean?
Less sugar has to be added to foods
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What is meant by immobilising enzymes?
Fixing them into an insoluble material so they are easier to handle and use
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What is an advantage of immobilised enzymes?
Do not contaminate the substance they are added to
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How are immobilised enzymes used?
In a continuous process
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Why are some people lactose intolerant?
Do not produce the enzyme lactase, so are unable to digest lactose sugar from milk
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What happens when lactose intolerant people have lactose?
Bacteria in their gut ferments the lactose, causing wind and diarrhoea
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What are transgenic organisms?
New organisms produced by genetic engineering
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What happens when genes are put into a different organism?
They produce the same proteins
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What do restriction enzymes do??
Cut DNA to leave sticky ends
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What are ligase enzymes used for?
Sticking other genes to the sticky ends of cut DNA
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How might bacteria be useful to diabetics?
Can be genetically engineered to produce human insulin
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How can transgenic organisms be used?
Can be cloned to produce identical copies, and large quantities of the same product
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What are plasmids?
Loops of DNA found in bacteria
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What are assaying techniques?
Techniques used to identify if the new gene has been successfully transferred
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What are DNA fingerprints?
Patterns, like bar codes, which are unique for each person
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What is electrophoresis?
A technique used to separate pieces of DNA
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What are radioactive probes used for?
To show up the DNA during DNA fingerprinting
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Other cards in this set

Card 2


What does the cell wall do in bacterial cells?


Maintains the shape of bacteria and stops them bursting

Card 3


What does DNA do in bacterial cells?


Preview of the front of card 3

Card 4


What are the four shapes of bacteria?


Preview of the front of card 4

Card 5


How do bacteria reproduce?


Preview of the front of card 5
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