RP06: Aseptic Techniques

Question 1

State 6 aseptic techniques

Answer 1

Wipe down surfaces with antibacterial cleaner, before and after experiment

Use a Bunsen burner in the work space so that convection currents draw microbes away from the culture.

Flame the wire hoop before using it to transfer bacteria.

Flame the neck of any bottles before using them to prevent any bacteria entering the vessel.

Keep all vessels containing bacteria open for the minimum amount of time.

Close windows and doors to limit air currents.

Question 2

Why is bacteria incubated at 25*C

Answer 2

To prevent growth of pathogens (harmful bacteria), at which occurs at higher temperatures

Question 3

How can you compare effectiveness of different antibiotics applied to same bacteria

Answer 3

Measure diameter and calculate area of zone of inhibition (clear zone) on the agar

Question 4

What does zone of inhibition indicate

Answer 4

It indicates the bacteria killed by the antibiotic.
The larger the zone the more effective the antibiotic.

If an antibiotic has very little or no zone of inhibition, the bacteria is likely resistant to the antibiotic.

Question 5

State hazards and precautions of this practical

Answer 5

Naked flame: keep away from flammable materials, tie hair up, wear goggles

Bacteria is a biohazard, use disinfect and wash hands, dispose of bacteria safely

Disinfectant is flammable, keep away from naked flame.

Question 6

Why should lid not be completely taped to Petri dish

Answer 6

To allow oxygen to enter Petri dish, preventing growth of harmful anaerobic bacteria

Question 7

Describe graph that can be plotted from results of this practical

Answer 7

A bar chart of zone of inhibition against antibiotic