Download Growing Microbes - Noadswood Science

L.O: To understand how microorganisms can
be safely cultured in a laboratory
Answers in your book:
1) Antibiotics do not work on which type of pathogen?
2) Drugs like paracetamol do not cure a disease, they only treat
the __________ of an illness.
3) Where do virus’ reproduce (replicate)?
4) What are the types of things that can be given to you in a
vaccination to make you immune?
5) Why should you always complete a course of antibiotics?
What does this symbol mean?
Why is it important?
Biohazard

If microorganisms that we want to use are
contaminated, the other microorganisms that
are present may produce harmful substances
or cause disease. It is only safe to use pure
cultures which contain one species.
Growing Micro - organisms
Grown in a culture medium containing
carbohydrates, minerals, proteins and
vitamins. This is usually agar in a petri dish.
Agar jelly can be poured when hot and sets
when cold. Alternatively a broth is a
culture flask might be used.
To grow micro-organisms you must
1) Sterilise the culture medium and petridish, this is done in an autoclave
2) Use Sterile inoculating loops (pass
through a flame) to transfer microorganisms
3) Seal the dish with adhesive tape to
prevent micro-organisms from the air
contaminating the sample/culture
What would happen if the
equipment wasn’t
sterilised?
Draw your agar plate out in your book:
For each section count the number of
colonies of bacteria that you can see.
Can we take a class sample of whether we found
less bacteria before cleaning our hands?
How does asking ‘the scientific community’ (the
class) improve the reliability of my conclusion?
Judge your partners sterile technique out of 10
 A rating of 1 would be very unhygienic.
 10/10 your partner is a perfect microbiologist
 Record this score in your exercise book
Next lesson we will compare the scores to how
contaminated the plates are.
Why do we need microbiology?
Microbiology is the study of microorganisms
(bacteria, viruses, fungi and protoctista) to small
to be seen by the naked eye.
 They have a vital role in decay, recycling nutrients,
disease and many other uses.
 Growing them allows us to learn about what
nutrients they need to survive and which
chemicals will kill them.
 We can also discover which are useful and which
are deadly!

What will happen?
Growing micro organisms Quiz
Method:
1) Sterilise the
inoculating loop
Dishes will be
incubated at 25°C
in school labs
2) Dip the loop in the bacteria
and spread it across the agar
3) Secure (but don’t
seal) the lid with tape
Questions:
1) Why do you sterilising the loop?
2) What does the agar do?
3) Why is the lid not sealed all the way around?
4) Why would you not want to culture your bacteria at 37OC ?
5) Why
23/05/2017are cultures incubated at higher temperatures in industry?