Microbiology Practical Flashcards
(16 cards)
What does Required Practical 2 investigate?
The effect of antiseptics or antibiotics on bacterial growth using agar plates and measuring zones of inhibition.
What is used to grow bacteria in this experiment?
A Petri dish with agar inoculated with a culture of bacteria.
What do you soak the paper discs in?
Different antibiotics or antiseptics.
How are the discs placed on the agar?
Using sterile forceps.
At what temperature is the dish incubated?
25°C.
Why is the Petri dish sealed and incubated upside down?
To prevent contamination and condensation dripping onto the culture.
What do you measure to assess effectiveness?
The diameter of the clear zones (zones of inhibition) around the discs.
What formula is used to calculate the area of inhibition zones?
Area = πr².
What does a larger zone of inhibition indicate?
A more effective antibiotic or concentration.
What is the independent variable in this practical?
The type of antibiotic used.
What is the dependent variable in this practical?
The size of the zone of inhibition.
What are some control variables in this practical?
Size of the discs, length of time soaked in antibiotic.
What is the purpose of this practical?
To test the effectiveness of different substances or concentrations on bacterial growth.
What can this practical help scientists discover?
Which antibiotics bacteria are resistant to.
What other factor could be varied in this experiment?
The concentration of the antibiotic or the type of antimicrobial chemical.
What is a key safety measure in this practical?
Using aseptic technique to avoid contamination.
