Microbiology Lab Practical 1 Flashcards
What are the general nutritional requirements for growth?
- water
- chemical element
The 4 physical factors that affect growth of an organism?
- salt and sugar concentration
- temperature
- oxygen gas
- pH
What ingredient is used as a solidifying agent in media?
agar
What type of organism makes up agar media?
algae
what percentage of organisms can be cultured in an artificial (laboratory) setting?
1 percent
By what process do most bacteria divide?
- binary fision
The temperature (in celsius) for the the freezer is?
-20 degrees
The temperature (in celsius) for refrigerator is?
4-10 degrees
The temperature (in celsius) for room temperature is?
20-25 degrees
The temperature (in celsius) for body temperature is?
37 degrees
What percentage of organisms require oxygen for growth?
50%
Define negative control?
- no growth
Define positive control?
- expect growth
Why might an organism fail to grow?
- none made it alive, dies before
- culture is bad
- physical conditions aren’t correct
Why might two different organisms show exactly the same growth features even if they aren’t supposed to?
- cross contaimination
what is a meniscus?
- the concave appearance artifact
What growth patterns are similar or different among the organisms tested?
- bacillus only had a pellicle
- staph/e.coli were both turbid
Is it possible for an organism to produce more than one growth pattern in the same tube?
yes
A film growth on the surface is a what?
pellicle
Even cloudiness is called what?
uniform fine turbidity
Growth adhering to the lass at the liquid/air interface is called what?
a ring
Suspended flakes or particles are called?
flocculent
A layer of growth at the bottom of the broth is called?
sediment
How do you calculate total magnification?
objective x ocular = total magnification