5.3-4 Culturinf Baceria And Preventing Growth

Question 1

How do bacteria divide/ grow?

Answer 1

Binary fission

Question 2

How to calculate mean division time?

Answer 2

Work out how many division occur within given time
Let’s call the amount ‘X’
2 to the power of the amount of division ( the X)= number of cells produced

Question 3

Step: disinfect Petri dish, state the reason for it?

Answer 3

To kill off any unwanted micro organisms

Question 4

Step: inoculating loop over a Bunsen burner, state the reason for it ?

Answer 4

Kills microbes on loop that might contaminate sample

Question 5

Step: Agar jelly, state the reason for it ?

Answer 5

Nutrients/ growth medium
Sugars for bacteria infused

Question 6

Step: Taping the Petri dish in a ‘X’ shape, State the reason for it ?

Answer 6

Allows O2 in but prevents contamination from air

Question 7

Step: Storing culture upside down, state the reason for this ?

Answer 7

Stops condensation forming and dripping onto sample

Question 8

Steps: incubate under 25C, state the reason for this step ?

Answer 8

Took cold for harmful pathogens to form

Question 9

What are three ways of preventing bacterial growth ?

Answer 9

Antibiotics: chemicals that can be used to kill bacteria or prevent them from growing (only worn in Bacteria)
Antiseptics: a disinfectant that is safe to use on human skin
Disinfectant: chemicals used to kill bacteria in the environment around us

Question 10

How do you know which antibiotic ,when testing them, is the most effective?

Answer 10

The largest inhabitation zone