Required Practical Investigate The Effects Of Antisepctis Or Bacterial Growth Flashcards
How are microorganisms cultured in a-lab
Bacteria are grown in a culture medium . This contains carbohydrates , minerals and other necessities the bacteria requires to survive
In a lab these cultures are not kept above 25 degrees because after this temperature harmful pathogens will start to grow.
Effects of antibiotics on bacterial growth
Place paper discs soaked in different types of antibiotics on an agar plate
Allow the antibiotic to diffuse into the agar jelly
Soon visible circles will appear around the paper discs . These are called inhibition zones . These are zones where the bacteria have been killed and are now unable to grow there
Always use a control . A paper disc that has been soaked in nothing or water , this is to see if anything other than the antibiotics is interfering with the survival of the bacteria
Leave the plate for 48 hrs at a round 25 degrees
How do you prepare an uncontaminated culture
Petri dish and culture medium must be sterilized before use to kill any unwanted microorganisms .
If an inoculating loop is used to transfer the bacteria you must sterilize it with a hot flame
After transferring the bacteria onto the petri dish lightly tape the lid to further prevent any microorganisms from getting to it
The petri dish should be stored upside down to stop drops of condensation from falling onto the agar surface
