Transcript B6- under the microscope

B6- under the microscope…
Bacteria and Virus
• Can be cultured using an aseptic
technique
• Viruses have a protein coat surrounding a
strand of genetic material. They only
reproduce in living cells, only attack
specific cells.
Reproduction of virus
Bacteria
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Flagellum for movement
Cell wall for shape
DNA control function
4 shapes…spherical, rod, spiral,
curved rods
Reproduce assexually called
binary fission
Survive in a range of habitats
Exploit a range of energy sources
Rapid growth can cause food to
spoil
Harmful microbes
• Diseases can be transferred through food,
water, contact and airborne droplets
• The enter the body, grow rapidly (the incubation
period) produce toxins and then symptoms
appear.
• Antibiotics and antivirals can control the disease
but overuse can render them ineffective and give
rise to bacteria that are resistance to antibiotics
through natural selection
• To avoid this you must only prescribe when
necessary and complete the dose
Natural Disasters
• Damage the sewer systems & water
supplies
• Damage to electrical supplied and rapid
food decay
• Displacement of people
• Disruption to services (eg transport &
emergency services)
Discoveries
• Pasteur- germ theory
• Lister- Antiseptics
• Fleming- penicillin
• You need to know what they discovered
and an understanding of the method(s)
they used
Useful Microbes
• Yogurt (sterilise equipment, pasteurise,
incubation, sampling, flavours/colours). Use of
lactobacillus bacteria that breaks down lactose
into lactic acid- this gives it the wobbly
consistency
• Brewing- fermentation is the anaerobic
respiration of yeast to produce alcohol…
Glucose->ethanol + carbon dioxide
C2H12O6 -> 2C2H5OH + 2CO2
Brewing Continued
• The main stages of brewing beer are… extracting sugar
from the source, add yeast, prevent entry of air,
clarfiying/clearing, drawing off, pasteurising, casking and
or bottling
• The process must be done in absence of oxygen to
create an environment for anaerobic respiration
• Pasteurisation is the sterilisation of product by taking it to
a high temperature momentarily to kill any unwanted
bacteria
• Distillation can make your beer stronger but is illegal to
do so without a license
• Different yeasts can tolerate different levels of alcohol
before they die :
Biofuels
• To make biofuels you need a large amount of
biomass generated by fast growing trees or by
transferring the energy of biomass by fermenting
them with bacteria of yeast.
• Advantages are- alternative to fossil fuels,
carbon neutral, no particulates
• If they are burnt at the same rate as they are
being produced and no other crop is being
cleared to grow crops for biofuels there will be
no increase is greenhouse gases.
• Disadvantages- potential habitat loss and
extinction of species
Biogas
• Made of methane, carbon dioxide and traces of
other gases. If there is less that 10% methane it
is explosive.
• Can be produced on a large scale using a
continuous flow method
• Can be used to generate electricity, produce hot
water or fuel for vehicles
• Biogas is made by fermenting waste and so is
susceptable to high & low temperatures
Gasohol
• A mixture of alcohol and petrol
• Used in cars in Brazil
• Good for countries that have lots of sugar
and small oil reserves
Life in Soil
• Sandy soil and clay soil have difference particle sizes.
Loam is a mixture of the two
• Humus is soil made of decomposing matter, rich in
minerals.
• Particle size effect air and water content.
• Soil needs as so the microscopic life can respire. If soil
has too much water it is impossible for respiration to take
place. Some water is essential however for both plants
and animals in the soil
• Aerating and draining can made the water and oxygen
levels.
• It is also important to mix up the layers and neutralise
the soil
Life in soil
• Earthworms burying organic matter,
aerate, drain, mix up layers and neutralise
the soil (WOW)
• Charles Darwin was the scientist who
discovered they unique important in the
life of soil
Life in Water
• Advantages- support, good for waste disposal, constant
water supply, less variation in temp
• Disadvantages- need to regulate water content of the
body (i.e contractile vacuoles), resistance to you
movement
• Photosynthesis of plants at depth depends on light,
temperature and mineral content of the water
• The amount of phytoplankton and zooplankton fluctuate
over seasons (you will need to interpret data on this
• Grazing food webs- start with a living producer
• Marine snow- decomposing matter falling form the
suface
Contractile Vacuoles
Eutrophication
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Fertiliser runs into the sea/lake
Rapid growth of algae
Plants in the dark die
Rapid growth of bacteria
Uses up all oxygen
Fish die
This is an accumulitive long term effect.
Other similar chemical include pesticides (DDT
on whales) due to bioaccumilation
Enzymes (again)
• Amylase, lipase, protease, can be used as
biological washing powder at moderate
temperatures
• Sucrose can be broken down to a sweeter
glucose or fructose by the enzyme
sucrase to make artificial sweeteners
• Lactose intollerance means the enzyme
lactase does exist so the lactose ferments
in the body causing diarrhoea and wind
Immobilising enzymes
• Mix the enzyme in an alginate and drop the
mixture into calcium chloride.
• Enzyme can be used over and over without
being contaminated
• Can be used in a continuous flow process
• These are used to make lactose free products.
• Immobilised lactose converts lactose to glucose
and galactose
Genetic Engineering (again)
• Identification of desired gene in one organism
• Removal of gene from DNA
• Cutting open the DNA in another organismrestriction enzyme
• Inserting the new gene into the DNA- ligase
enzyme
• Transgenic organism can be cloned to produce
identical copies
• Gene works in transgenic organism
Making Insulin
• The gene for producing human insulin is cut out
of human DNA
• A loop of bacterial DNA is cut open
• The insulin gene is inserted into the loop
• The loop is inserted into the bacterium
• The bacteria are able to produce insulin
• Transgenic bacteria are cultured by cloning
• Large quantities of insulin are harvested