Aseptic technique + Growth of Bacteria

Question 1

What is the aseptic technique used for?

Answer 1

Ensure that the petri dish is thoroughly sterilised (not contaminated with unwanted bacteria)

Question 2

What is culture

Answer 2

the growing of microorganisms

Question 3

How to do the aseptic technique

Answer 3

1. Clean hands and workspace
   Ensure dishes and cultures are sterilised
2. Inoculating loops (used to transfer culture onto petri dishes) must be sterilised by being passed through a bunsen burner.
3. Open the vial of sterilised water and pass the rim through the bunsen burner
4. Dip inoculating loop into the sterilised water and spread it onto the agar
5. Replaced lid secured with tape (not all the way for respiration)
6. Pass the inoculating loop through the bunsen burner again
7. Stored upside down to prevent condensation
8. Stored at 25 degrees celsius.

Question 4

How to calculate the final number of bacteria (growth of bacteria formula)

Answer 4

Initial number of bacteria x 2^number of divisions

Question 5

How do you calculate the number of divisions

1 initial bacteria. Bacteria B with mean division time of 15 minutes is left for 8 hours. Calculate the final amount of bacteria.

Answer 5

How long the sample is left to grow / how long it takes to divide

15 divided by 60= 0.25

8/0.25 hours = 32 divisions.

1x2^32= 4294967296

4.29x10^9