What is important about the Petri dishes used to make agar plates?
They are made of glass
They are sterilised before use
They are filled with agar
Which of these is a method used in aseptic technique?
Touch the agar to make sure it is cool
Remove the Petri dish lid completely
Heat the inoculating loop to red hot in the Bunsen flame
Why must nitrogen be included in the nutrient broth used to grow microbes?
For energy
For respiration
For protein synthesis
Which piece of apparatus is used to transfer bacteria onto an agar plate?
Pipette
Inoculating loop
Petri dish
At what temperature should inoculated plates be incubated in a school laboratory?
25°C
35°C
45°C
What assumption is made when using agar plates to count bacteria in a sample?
That all bacteria are dead
That all bacterial colonies are the same
That all bacterial colonies are formed from just one cell
The mean division time for bacteria population A is 20 minutes. If an experiment begins with one bacterium, how many bacteria will be present after two hours if kept under optimal conditions?
6
64
128
What is the function of the water jacket in a fermenter?
To allow nutrients in
To test the pH
To cool the fermenter
What is the function of the filter on the air inlet in a fermenter?
To stop microbes leaving the fermenter
To prevent contamination of the fermenter
To allow acids and alkalis into the fermenter
How does keeping food in a freezer avoid spoiling?
It stops bacterial growth
It slows bacterial growth
It kills bacteria