Micro lab exam 2 Flashcards
UV-A wavelength
315-400 nm
UV-B wavelength
280-315 nm
UV-C wavelength
100-280 nm
Spontaneous mutation
arise occasionally in all bacteria and develop in the absence of any agent
Induced mutation
result of a bacterium’[s exposure to a mutagen, which is a physical or chemical agent
Viruses that infect bacteria:
bacteriophages
Lytic cycle:
Phage attaches to bacteria cell
Injects DNA
Viral genome commands host cell to produce more DNA which make more phages
Host lyses and releases phages
Lysogenic
Phage DNA integrates into chromosome called prophage
dormant until cell is stressed then goes to lytic stage
Plaque
lysis of bacterial cells growing in a lawn on an agar plate
Plage titer =
PFU / (Volume x Dilution)
Plaque Assay
Diluted phage is added to bacterial culture and then put into agar and agar poured into plate
propagated transmission
disease transmitted from person to person
Incident rate =
(number new cases / size of at-risk population at midpoint of time ) x K
Prevalence rate =
(number of existing cases / size of at-risk population at midpoint of time period ) x K
Hemagglutination
general term applied to any agglutination test in which clumping of red blood cells indicates a positive reaction
Type A blood:
RBCs with A antigen
Produces anti-B antibodies
Type B blood:
RBCs with B antigen
produces anti-A antibodies
Types AB blood
RBCs with both A and B antigens
Lack anti-A and anti-B antibodies
Type O blood:
RBCs lack A and B antigens
Produces both anti-A and anti-B antibodies
Agglutination (clumping) of anti-A serum means what?
type A
Rh factor is shown by what antigen?
D
Universal donor
O- blood
Universal recipient
AB+ blood
Thermophiles
grow at greater than 45 degrees
Obligate thermophiles
will not grow below 40 degrees
Facultative thermophiles
grow below 40 degrees
extreme thermophiles
grow best above 80 degrees
Acidophiles
live below pH 5.5
Neutrophiles
live in pH between 5.5 and 8.5
Alkaliphiles
live above pH 8.5
obligate (strict) aerobes
require oxygen; grow at top of media
facultative anerobes: grow everywhere but denser at top
grow in presence or absence of oxygen
obligate anaerobes; grow in lower region
cannot have oxygen
aerotolerant
don’t require oxygen but aren’t affect by it; grow unifromly
microaerobes
lower than atmospheric levels of O2
Thioglycollate is used
to determine if an organism needs O2
Eosin Methylene Blue Agar (EMB) inhibits growth of what?
Gram + organisms
EMB results:
normal color: non-lactose fermenters
dark purple to black: vigorous lactose fermenters
pink to dark purple: less aggressive lactose fermenters
green: e.coli
Hektoen enteric Agar (HE) results:
black: Salmonella
Shigella: green
Other: yellow or salmon
susceptible
harmed by a thing
what family are coliforms part of
Enterobacteriaceae and are lactose fermenting
DSLB stands for
Double Strength Lactose Broth
SSLB stands for
single strength lactose broth
Bactericidal vs Bacteriostatic
kills microbe stops growth does not kill
Kirby Bauer test or disk diffusion test
put the antimicrobial in middle of lawn of bacteria and measure the diameter
