Micro-Organisms Flashcards
What form of cell division does bacteria use?
Binary fission
What does bacteria growth depend upon?
The availability of nutrients and other suitable conditions
How often do bacteria replicate?
Every 20 minutes
What are the ways to culture bacteria?
In a nutrient broth solution or on an agar plate
What does a liquid broth solution provide?
Carbohydrates for energy, nitrogen for protein synthesis, plus other minerals.
What are pathogens?
Bacteria that cause disease
Why is it important to sterilise a petri dish before use?
To prevent other bacteria from competing for resources
What is used to transfer bacteria?
An inoculating loop which is sterilised in a bunsen flame
How hot are agar plates incubated at and for how long
24-48 hours at 25 degrees, to make sure they aren’t harmful to humans (37 degrees)
How can we be confident that predictions of growth are correct?
Because bacteria multiply at regular intervals
How do we calculate the number of bacteria in a population?
- Calculate how many times the bacteria divide in said time (how many times per hour, how many hours)
- How many in the population (bacteria at the beginning times two to the power of however many divisions)
How can we slow bacterial growth?
- By lowering the temperature
- When frozen bacteria stop growing but don’t die
- When cooked bacteria die
What do fermenters do?
Grow bacteria on an industrial level
What are fermenters made out of?
A metal that won’t corrode
What does a steam inlet do for a fermenter?
It sterilises the inside of the container and stops competition
What gives nutrients to a fermenter?
A nutrient inlet
What does a water jacket do for a fermenter?
It keeps a constant temperature
What does an air inlet do for a fertiliser?
Provides a source of oxygen
Why is an air inlet filter necessary?
Stop micro-organisms from getting in
What do stirring paddles do in a fermenter?
Keeps the mixture inside the fermenter agitated (stirred)
What do pH probe and intake valve for acid and alkali do for a fermenter
The pH inside the fermenter is monitored to check it is at the optimum value
What happens after penicillium has been in a fermenter for 200 hours?
It is removed and filtered. This removes fungal cells, leaving the product penicillin which will need to be treated chemically before use.
