2.7 Microorganisms & Their Applications Flashcards
What is a micro organism?
A microscopic living organism
Types of microorganisms
Viruses, bacteria, microscopic fungi, protists
What is the name for a micro organism that causes disease?
Pathogen
How are microorganisms grown
On a petri dish in agar jelly, which provides them with nutrients
1 colony -
1 bacterium
What affects the rate at which bacteria grow?
Temperature
Aseptic technique Purpose 
So the surrounding bacteria don’t contaminate the agar plate sample
Aseptic technique steps
- Inoculating loop is sterilised by heating it in the Bunsen burner flame
- Lift stopper from culture tube and “flame it” - ensures bacteria drifting out are killed
- Collect bacteria with loop, flame tube mouth again to kill bacteria drifting in
- Partially raise petri dish lid, so bacteria from the air Don’t contaminate it. Draw the loop across the surface.
- Flame the wire loop again- kills bacteria left on the loop so they don’t contaminate the environment
Why incubate human pathogen is at 37° C
Human pathogens grow better at body temperature
Storing food at room temperature effect on bacterial growth
Bacterial growth is uncontrolled and rapid
Storing food in refrigerator effect on bacterial growth
Slows bacterial growth
Storing food in freezer affect on bacterial growth
Stops bacterial growth
What do very high temperatures do to bacteria
Kills bacteria
Conditions controlled in the production of penicillin
Temperature pH, oxygen level (needed for respiration), nutrient level (starvation levels)
Penicillin is extracted after how many hours
~200
