Lab 3

Question 1

What are the 3 main reasons aseptic technique is important?

Answer 1

1) Safety: When working with cultures to minimize potential contamination of you and your neighbor
2) Sterility: When working with sterile substances to avoid contamination
3) Purity: When working with pure cultures

Question 2

How do you aseptically pour tryptic soy agar (TSA) plates?

Answer 2

1) Flask closed; open and pass over the flame
2) Pour into petri dish
3) Recap petri dish and pass the flask over the flame again
4) Recap the flask
*All of this must be done within ~1.5 feet of a flame

Question 3

How do you aseptically transfer a bacterial pure culture?

Answer 3

1) Sterilize the loop with a flame
2) Pass the lid of the culture’s tube over the flame
3) Open tube, put loop in the tube and collect bacteria
4) Close bacteria tube
5) Open the sterilized petri dish or tube and deposit bacteria with the loop
6) Re-sterilize loop
*All must be done within ~1.5 feet of a flame

Question 4

When working with ‘dry’ bacteria (i.e. in a petri dish of agar), why is it important to slowly put the loop into the flame slowly when re-sterilizing?

Answer 4

So you don’t accidently allow the bacteria to go airborne