Practical microbiology

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Year 5 Practical Microbiology Homework
<this is on Edmodo, Twitter and FB>
You need to know how to do ‘aseptic technique’ in detail! There has
been a 6 mark question on it.
Choose one of these tasks and complete for homework.
Due Monday 2nd Feb (bring in red book or email document to JEM)
How will this be marked: Effort and Attainment Grade
• Complete an illustrated flow chart to describe every step we did
today. Use Google images for pictures?
• Complete a comic strip to show what we did today (comic life
app? Or similar?)
• Complete the 6 mark question in from your long-answer booklet –
do in your red book and check compare to mark-scheme.
If anyone wants this power point with images – email me
Growing microorganisms in Petri dishes to demonstrate sterile
technique and growing pure cultures
Aim – to transfer E.coli from culture medium to petri dish
without contamination
Lawn of
bacteria
What is in the petri dish?
• Agar = jelly
• Growth medium:
– Nutrient agar
– Blood agar etc
the use of pre-inoculated agar in Petri dishes to evaluate the
effect of disinfectants and antibiotics
Aim: to add samples of antibiotics or disinfectants to
the bacterial lawn to see which is the most effective at
killing bacteria
Antibiotics:
X8
Allergies!
Disinfectants:
Savlon
Virkon
Hydrogen
peroxide
Sterile water
Sealing & labelling your dishes
The lid of the Petri dish should be secured with
adhesive tape to prevent microorganisms from
the air contaminating the culture.
Label
Tiny writing around edge!
On base
Initials, date, contents
Practise table drawing for controlled assessment
Growing microorganisms
In school and college laboratories, cultures should be incubated at a
maximum temperature of 25 °C, which greatly reduces the likelihood
of growth of pathogens that might be harmful to humans.
In industrial conditions higher temperatures can produce more rapid
growth.
Specification
m) Uncontaminated cultures of microorganisms are required for investigating the action of
disinfectants and antibiotics. For this:
• Petri dishes and culture media must be sterilised before use to kill unwanted microorganisms
• inoculating loops used to transfer microorganisms to the media must be sterilised by passing
them through a flame
• the lid of the Petri dish should be secured with adhesive tape to prevent microorganisms from the
air contaminating the culture.
n) In school and college laboratories, cultures should be incubated at a maximum temperature of 25
°C,
which greatly reduces the likelihood of growth of pathogens that might be harmful to humans.
o) In industrial conditions higher temperatures can produce more rapid growth.
• Suggested ideas for practical work to develop skills and understanding include the following:
• investigate the effectiveness of various antibiotic discs in killing bacteria
• growing microorganisms in Petri dishes to demonstrate sterile technique and growing pure
cultures
• the use of pre-inoculated agar in Petri dishes to evaluate the effect of disinfectants and antibiotics
•

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