Growing and Investigating bacteria

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Growing and Investigating bacteria by Mind Map: Growing and Investigating bacteria

1. why?

1.1. to find out more about them

1.1.1. what nutrients they need to grow

1.1.2. therefore how best to kill them ie which chemicals eg disinfectants and antibiotics destroy them

1.2. culture = grow large nos of microorganisms

1.2.1. Employee

1.2.2. Employee

1.3. many can be cultured in the lab

1.3.1. bacteria are most commonly cultured

2. Steps to grow useful microorganisms

2.1. sterilise petri dish

2.1.1. use heat

2.1.2. often use special autoclave oven

2.1.3. can be bought ready sterilised

2.2. sterilise nutrient agar

2.3. sterilising kills off unwanted microorganisms already in the dishes or jelly

2.4. inoculate the sterile agar with the microorganisms you want to grow

2.4.1. sterilise the inoculating loop

2.4.2. dip loop in suspension of bacteria

2.4.3. zig zag traces of bacteria across surface of agar

2.4.4. put petri lid on quickly

2.4.5. seal dish with tape but not all way around so oxygen can get into dish and stop nasty anaerobic bacteria growing

2.5. incubate (keep warm) the sealed petri dishes

3. Growing microorganisms in the lab

3.1. give them a culture medium

3.1.1. liquid or gel containing nutrients

3.1.2. contains carbohydrate, minerals and other chemicals

3.1.3. usually is agar jelly

3.2. also need warmth and oxygen to grow

3.3. pour hot agar in petri dish, let cool and set then add microorganisms

3.4. remember the risk of mutation - a change in DNA of the bacteria may produce a harmful pathogen

3.5. also make sure that the culture remains pure (or uncontaminated) so just the bacteria you are growing/testing so that results of investigations are valid

3.5.1. from your skin, soil, air, water around

3.6. only culture at max of 25 degrees on schools as dangerous pathogens may be grown above that temperature

3.7. industrial conditions = often higher temperatures allowing faster groeth