Microbiology Questions Flashcards
(15 cards)
What is the focus of Required Practical 2: Microbiology?
Investigating the effect of antiseptics or antibiotics on bacterial growth using agar plates and measuring zones of inhibition.
What is the purpose of aseptic technique in microbiology?
To prevent contamination of cultures with unwanted microorganisms.
What should you do before and after working with bacteria?
Wash your hands.
How should you prepare the work surface before and after the experiment?
Sterilise it.
Why use a sterile Petri dish and sterile agar?
To ensure no microorganisms are already present.
How do you sterilise an inoculating loop?
By holding it in a Bunsen burner flame until it glows red.
Why work near a Bunsen burner when transferring bacteria?
The hot air helps prevent airborne microorganisms from contaminating the culture.
How should you handle the lid of a Petri dish to reduce contamination?
Tilt the lid open slightly and minimise the time it is exposed to air.
What should be done to the neck of the culture medium before use?
Flame it to prevent unwanted microorganisms from entering.
Why shouldn’t you seal the Petri dish completely with tape?
To avoid creating anaerobic conditions, which could promote growth of pathogens.
At what temperature should the dish be incubated, and why?
25°C – lower than the optimum for pathogen growth.
What would indicate the most effective antibiotic or antiseptic?
The largest zone of inhibition around the disc.
What kind of conclusions might you be asked to make from data?
Which antibiotic or concentration is most effective and possibly safest.
What is a useful control in this experiment?
A paper disc with no antibiotic to compare the effect of antibiotics.
Why is a control disc with no antibiotic important?
It shows whether bacterial growth is affected without the antibiotic present.
