Lab Quiz Cards Flashcards
A single medium, such as trypticase soy agar can support the growth of all organisms in the lab. True or false?
False - there is no medium that support the growth of all organisms.
When preparing a slide, a liquid organism would not require the initial drop of water. True or false?
True.
The total magnification of the microscope is the product of the ___ lens and the objective lens magnification.
- focal piece
- eyepiece
- nose piece
eyepiece
Why is sterile technique so important? Give two reasons.
- prevent contamination of the culture from environmental organisms
- prevent culture of contaminating you or others
Why should plates be inverted when being incubated?
- To view the cells correctly
- To avoid condensation
- To avoid outside contamination
to avoid condensation
All of the following are true when you use the oil immersion lens except:
- you are using the 100x objective
- you are adding a drop of oil to compensate for refraction
- you are adding a drop of oil to compensate for reflection
you are adding a drop of oil to compensate for reflection
The resolving power of a microscope is described as the ability of the microscope to
clearly separate two objects that are very close together
specimens can be observed at the atomic level using an
atomic force microscope
What kind of charge do basic dyes have?
positive
what is the correct order in the basic staining procedure?
smear, fix, stain
what are the two types of bacteria and what are their colors?
gram positive - purple
gram negative - pink
is applicable to only a few groups of bacteria and usually shows the spores as green structures among a background of pink cells
endospore stains
what is a diluent?
the liquid used to dilute a sample
you have added .1ml of the original culture to 9.9ml of water. How much have you diluted the sample?
1:100
what is serial dilution?
preparing a dilution of the original culture in multiple steps
All of the following are true of viable bacteria except
- they are not growing
- they are growing and dividing
- can be measured by plate counts
they are not growing
In an agar deep, where do obligate aerobes grow?
at the surface of the agar deep
what is an agar deep?
test tube filled almost to the top with agar
what the thermal death time (TDT)
minimum time required to kill all microbes at a set temperature
what is the thermal death point (TDP)
the lowest temperature at which all microbes are killed in a culture within a given time
Out of the following microorganisms, which one would penicillin be able to kill?
- staphylococcus epidermidis
- e. coli
- pseudomonas aeruginosa
staphylococcus epidermidis
liquid media containing heat-sensitive components would best be sterilized by
membrane filtration
the zone of inhibition produced by a bacteria that is sensitive to an antibiotic will depend on….
the size of the antibiotic molecule and the concentration of antibiotic on the disc
What are two precautions that need to be taken when dealing with UV light?
do not look directly at it and do not put it to your skin because it causes mutations
what are the typical conditions for sterilization?
121 degrees celsius at 15 psi for 15 minutes
what is the zone of inhibition?
region that surrounds a chemical saturated disc where bacteria are unable to grow
acinetobacter is
naturally competent
what is DNA transformation?
transfer genes of one bacterium to another
Acinetobacter StrS cells will grow on TSY + streptomycin plate. True or false?
False
propionbacterium will grow in what conditions?
- plate incubated aerobically
- plate incubated anaerobically
- surface of the agar deep
- bottom to middle of the agar deep
plate incubated anaerobically/bottom to the middle of the agar deep
what happens to staphylococcus aureus when it is plated on a mannitol salt plate?
it will appear yellow because it is able to utilize mannitol
why is salt used in the mannitol salt plate?
to prevent the growth of gram negative bacteria
A commensal organism is harmful for the host. True or false?
false
a pink color on macconkey agar tells us what?
lactose has been fermented by a gram negative bacteria
the indole test indicates whether the bacteria has the enzyme to break down what?
tryptophan
what happens when there is an indication of tryptophan in a broth?
a red/pink ring will form in the indole test when kovacs regeant is added
why is methyl red added to each of the sugar fermenting tubes
because it is a pH indicator
what is one coccus gram negative bacteria from your throat culture?
moraxella catarrhalis
what is a beta hemolytic bacteria that may be found in a throat culture?
streptococcus pyogenes
what does the oxidase test indicate?
is cytochrome c oxidase is present in a bacteria
what is a indicative oxidase test?
a dark purple blue color
ELISA stands for
enzyme linked immunosorbent assay
the elisa assay technique is based on the formation of
antigen-antibody complex
what does lauryl lactose sulfate selectively enrich for
coliforms
what is the best way to measure the presence of viable bacteria that may not form colonies on plates easily
multiple tube fermentation method
three characteristics of indicator organisms
- non pathogenic
- highly occurring in feces
- easy to detect compared to waterborne pathogens
what kind of medium is the brilliant green broth?
selective
what kind of growth does brilliant green broth support?
coliforms
if all the tubes in your MPN method for determination of viable bacteria are positive, then you will start with
a diluted sample of the water
