5.17B **Biology Only** - Aseptic Technique Flashcards
What are microorganisms?
Microorganisms are very small living organisms that require growth in the lab for study.
What is culture medium?
Culture medium contains carbohydrates for energy, minerals, proteins, and vitamins.
What are the two ways to grow microorganisms in the lab?
- In nutrient broth solution 2. On an agar gel plate.
How is nutrient broth solution prepared?
A suspension of bacteria is mixed with sterile nutrient broth and stoppered with cotton wool.
What is the purpose of shaking the flask in nutrient broth solution?
Shaking provides oxygen for the growing bacteria.
How is an agar gel plate made?
Hot sterilised agar jelly is poured into a sterilised Petri dish and left to cool and set.
What is the role of inoculating loops?
Inoculating loops are dipped in a microorganism solution and spread over the agar evenly.
What is the incubation process for agar gel plates?
The lid is taped on, and the plate is incubated upside down for a few days.
Why must Petri dishes and culture media be sterilised?
To prevent contamination with other microorganisms that could compete for nutrients or produce pathogens.
How are inoculating loops sterilised?
By passing them through a flame.
Why should the Petri dish be stored upside down?
To prevent condensation from the lid landing on the agar surface.
Why should the lid of the Petri dish be sealed with tape?
To stop airborne microorganisms from contaminating the culture.
What is the optimal incubation temperature for cultures?
The culture should be incubated at 25 degrees Celsius.
What happens if the culture is incubated at 37 degrees Celsius?
Bacteria that could be harmful to humans are more likely to grow at this temperature.
