1-2 Flashcards
what does a media/medium contain?
carbon sources
nitrogen
vitamins
minerals
Microbiological media usually comes in what form?
dehydrated power
dissolves in water
what converts a liquid medium into a solid medium?
agar
how can media be sterilized?
autoclaving
filtration
what is a chemically defined medium?
composition and amount of each ingredient is known
what is a chemically undefined medium/complex media?
composition and amount of each ingredient is not known
what is an enriched medium?
additional nutrients added to encourage growth of fastidious (difficult to grow) MO
what is a differential medium?
differentiates b/w MO based on their ability to conduct a metabolic process
what is a selective medium?
contains ingredients that select for a particular type or group of MO
what is a maintenance medium?
allows for the maintaining of MO over a long period of time
what is agar composed of?
polysaccharides isolated from red algae
when does agar melt?
100 degrees Celsius
when does agar solidify
45 degrees Celsius
can agar be melted and solidified repeatedly?
yes
what are some important characteristics of agar?
Most MO cant use it as a carbon and energy source
converts a liquid medium into a solid medium
necessary to kill endospores
what is an autoclave?
fancy, expensive pressure cooker
what is an autoclave used for?
sterilization of liquid media
glassware
metal ware
what can not be used with an autoclave?
heat sensitive materials
what are the conditions for reaching sterilization with an autoclave?
121 degrees Celsius
15 PSI
15 minutes
what is one form of media?
liquid/
NUTRIENT broth
what is another form of media?
semisolid (low concentration of agar added)
like jello
what is the third form of media?
solid
1.5% agar concentration added
what concentration of agar is needed t convert a broth/ liquid medium into a solid medium
1.5% agar
what is a slant? refer to pic in p.p
angled in tube
what is a deep?
agar in test tube and not angled
what is a petri dish?
agar in a dish with two halves
How do you prepare a medium/agar?
weigh agar
mix Agar
dispense agar
autoclave
*for agar plates, pour sterilized medium in petri dish
how are endospores killed?
only in an autoclave
