Week 1 Labs Flashcards
Culture with one type of bacterial species in known as?
Pure
A culture with more then one type of bacteria is known as?
Mixed
Culture with unwanted organisms is called?
Contaminated
What is the purpose of the aseptic techinque?
Avoid contamination
How bacterial growth is bacterial growth detected on broth medium? Solid medium?
Turbidity (cloudness), colonies.
What is the function of an autoclave in media preparation?
To sterilize the media of both vegetative cells and spores.
How high should the bunsen burner flame be?
10cm high
What part of the bunsen burner flame is hottest?
Blue cone is the coolest and the top of the cone is the hottest.
Subcluturing
Providing the organism with a fresh medium
inoculum vs inoculation
The organism is the inoculum while the process of transferring them to a new medium is inoculation.
incubation period and temp for cultures?
30-37 C for 18-25 hours
Sterilization
process that achieves a microbe-free medium
Vegetative cells vs. Spores
Vegetative is actively growing and sores of environmental resistant.
Autoclave specifications
15psi, 121 C, 15-20 minutes.
Why do you flame the loop prior to placing it into a culture?
To prevent contamination of both the primary and new culture.
How often must bacteria be sub-cultured from a broth to maintain culture viability?
48 hours
Flocculence, turbidity, pellicle
Flocculence- clumps
Turbidity- cloudness
Pellicle- film growth on surface.
Possible sources of contamination when performing broth-broth sub culturing.
Loop not being sterilized properly, contamination by placing the cap on bench.
How are broth cultures used in microbiology?
Used for testing and research.
How are slant cultures used in microbiology lab and what are its advantages over other types of cultures?
Maintain stock cultures. Take up less room and less likely to be contaminated.
What is added to broth to produce a solid medium?
Agar
At what temp does solid medium melt? What temp does it solidify?
Melts at 97-100 C and solidifies at 42 C
What is the ideal pouring temp of a solid medium?
50 C
inoculum size
the needed concentration of microorganisms for a standard test
