Growing Microbes L.O: To understand how microorganisms can be safely cultured in a laboratory Answers in your book: Antibiotics do not work on which type of pathogen? Drugs like paracetamol do not cure a disease, they only treat the __________ of an illness. Where do virus’ reproduce (replicate)? What are the types of things that can be given to you in a vaccination to make you immune? 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 Sterilise the culture medium and petri-dish, this is done in an autoclave Use Sterile inoculating loops (pass through a flame) to transfer micro-organisms 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: Dishes will be incubated at 25°C in school labs 1) Sterilise the inoculating loop 2) Dip the loop in the bacteria and spread it across the agar 3) Secure (but don’t seal) the lid with tape Questions: Why do you sterilising the loop? What does the agar do? Why is the lid not sealed all the way around? Why would you not want to culture your bacteria at 37OC ? Why are cultures incubated at higher temperatures in industry? In school and college labs, cultures should be incubated at a maximum temperature of 25°C which greatly reduces the likelihood of pathogens growing that might be harmful to humans. In industrial conditions higher temperatures can produce more rapid growth. 22/04/2017