Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
23 Cards in this Set
- Front
- Back
mixed culture
|
culture with more than one type of microorganism
|
|
Why is agar such a good gelling agent?
|
Majority of microorganisms do not have the enzymes to degrade the agar, and it does not melt unless it is at boiling temperature.
|
|
What do microorganisms need to grow?
|
nitrogen, energy source (e-), carbon, water
|
|
defined medium
|
when the exact components and amounts are known
|
|
complex medium
|
if the medium contains peptones (extracts from yeast, veggies, meat, etc)
|
|
streak plate
|
method of diluting a bacterial sample on a solid plate
|
|
selective medium
|
inhibits growth of certain groups of microorganisms (EMB- inhibits gram +)
|
|
EMB
|
-eosin methylene blue
-inhibits gram + -can also differentiate between lactose fermenting or non-fermenting gram (-) because it contains sugars (lactose and sucrose), and if organism ferments sugar to acid, then it will absorb dye, turning it black) |
|
enriched medium
|
promotes growth of certain organisms (media with something extra like blood or yolk)
|
|
differential medium
|
differentiates between organisms (by pH, lactate, etc)
|
|
Mannitol salt agar
|
-contains carbohydrate and pH indicator (yellow if acidic, red if basic). therefore if organism ferments sugar, it will give off a yellow halo
-also high in salt content (7.5%) so organisms that cannot tolerate high salt will not grow |
|
MacConkey agar
|
contains lactose and neutral red pH indicator (turns red when acidic)
|
|
blood agar
|
microorganisms that secrete hemolysin (lyses blood) which will "eat" the blood cells around the colony so you get a clear area around it, or green if it is a hemolysin that partially lyses
|
|
Time before you must transfer your slant pure culture
|
7-10 days
|
|
coliforms
|
gram negative lactose fermenting bacili (rod shaped), non-endosporm forming. ex) e. coli
|
|
facultative
|
"optionally"
|
|
normal flora
|
mostly gram + bacteria that reside on human skin
|
|
propionibacterium
|
normal flora found in dairy products too. found deep in skin near sebaceous glands.
|
|
types of colonies you might get from forehead culture
|
a. large, convex, opaque, white (staph)
b. flat, tan, viscid c. medium, opaque, convex, smooth, pink/brown (propionibacterium) |
|
Yeast are eukaryote or prokaryote?
|
eukaryote
|
|
S1 (Gould) agar
|
-prevents gram + (contains SLS which disrupts the membrane)
-Trimethoprim- antibiotic for facultative anaerobic gram- |
|
pseudonoma
|
-produces pigment around the colony which diffuses into media
-gram-, aerobes |
|
bacillus
|
gram +, endospore forming bacteria
|