MICROBIO 303 Exam test quiz and
answers graded A+
Mycoplasma species - ANS✅✅- Bacterial cells not enveloped by a cell wall
Gram Negative - ANS✅✅- Bacterial cells stained pink at the completion of a gram stain
- Braun Lipoprotein
- Periplasmic space
- Outer membrane
- Might contain an endotoxin
- Monolayer of peptidoglycan
- Contains an LPS layer
Archaea - ANS✅✅- Cell membranes contain L-glycerol
- Contains pseudomurein
- Cell membrane contains ether bonds instead of ester bonds
- Cell membrane contains isoprenes
Mycoplamsa species - ANS✅✅- Bacterial cells not enveloped by a cell wall
Gram Positive - ANS✅✅- Techoic acid
- Many layers of peptidoglycan
- Bacterial cell that retains crystal violet during a gram stain
Mycobacterium species, or other acid-fast bacteria - ANS✅✅- Mycolic acid
Mushroom's are usually considered part of the microbial world because their fungal hyphae are
microscopic. Some mushrooms have a fruiting body known as a ______ that is visible to the naked
eye above ground. - ANS✅✅basidiocarp
,A 10^-1 dilution is performed 5 times on the same sample as mathematically depicted above. To find
the cumulative dilution, each dilution should be _____ together. The cumulative dilution therefore
equals ______. - ANS✅✅multiplied; 1*10^-5
What technique is most likely to be used for sterilizing a vitamin solution that is added to culture
media? - ANS✅✅***
In general, when performing spread plates, ______ mL of cell suspension is added to the plate to
prevent the formation of a microbial _______. Adding more than 1 mL of cell suspension to an agar
plate will result in a ______. Adding less than 1 mL of cell suspension to an agar plate will result in a
______. - ANS✅✅0.1
lawn
concentration
dilution
A limitation of microscopic methods for counting cells is that - ANS✅✅microscopic cells counts
enumerate cells that were both living and dead at the time of sampling
A bacterium adapted to life in hot environments would be more likely to have - ANS✅✅cell
membranes with a greater number of saturated fatty acids
Which two domains of life form a monophyletic group (aka: are most closely related)? -
ANS✅✅Archaea
Eukaryotes
Correctly order the steps in Koch's Postulates - ANS✅✅1. The microorganism must be found in
abundance in all organisms suffering from the disease, but should not be found in healthy organisms
2. The microorganism must be isolated from a diseased organism and grown in pure culture.
3. The cultured microorganism should cause disease when introduced into a healthy organism
4. The microorganism must be reisolated from the inoculated, diseased experimental host and
identified as being identical to the original specific causative agent.
Which compound is a constituent of both pseudomurein and peptidoglycan? - ANS✅✅N-
Acetylglucosamine
, Which kind of media contains highly nutritious materials or specific compounds that enable certain
kinds of microbes to grow? - ANS✅✅Enriched media
Which kinds of media contains a dye or other indicator that responds to metabolic reactions during
growth to identify a specific organism? - ANS✅✅Differential
Which kind of media is used to culture fastidious microbes? - ANS✅✅Enriched media
Sabouraud Glucose Agar with chloramphenicol is used to culture fungi. The chloramphenicol is used
to inhibit the growth of bacteria. Which of the statements below correctly describes this media? -
ANS✅✅- This media selects for fungi
- This media selects against bacteria
If 1 mL of culture is transferred to 99 mL of sterile media, and then 1 mL of that dilution is
transferred to 9 mL of sterile media, and finally 0.1 mL of that dilution is transferred to a plate, what
is the final dilution? - ANS✅✅1*10^-4
(1/100)*(1/10)*(0.1) = 1e-4
If 1 mL of culture is transferred to 99 mL of sterile media, and then 0.1 of that dilution is transferred
to 9.9 mL of sterile media, and finally of that dilution is transferred to a plate, what is the final
dilution? - ANS✅✅1*10^-3
There are so many microbes is a single mL of culture, it is very difficult to perform one dilution to
produce countable cells. Microbiologists need to perform a dilution series, where multiple dilutions
are performed in sequence to arrive at the correct dilution.
Dilutions are cumulative. Multiply the series of dilutions together to find the final dilution value.
If 2 serial dilutions are performed, each with a dilution of 0.1, what is the cumulative dilution? -
ANS✅✅1*10^-2
0.1 * 0.1 = 0.01
answers graded A+
Mycoplasma species - ANS✅✅- Bacterial cells not enveloped by a cell wall
Gram Negative - ANS✅✅- Bacterial cells stained pink at the completion of a gram stain
- Braun Lipoprotein
- Periplasmic space
- Outer membrane
- Might contain an endotoxin
- Monolayer of peptidoglycan
- Contains an LPS layer
Archaea - ANS✅✅- Cell membranes contain L-glycerol
- Contains pseudomurein
- Cell membrane contains ether bonds instead of ester bonds
- Cell membrane contains isoprenes
Mycoplamsa species - ANS✅✅- Bacterial cells not enveloped by a cell wall
Gram Positive - ANS✅✅- Techoic acid
- Many layers of peptidoglycan
- Bacterial cell that retains crystal violet during a gram stain
Mycobacterium species, or other acid-fast bacteria - ANS✅✅- Mycolic acid
Mushroom's are usually considered part of the microbial world because their fungal hyphae are
microscopic. Some mushrooms have a fruiting body known as a ______ that is visible to the naked
eye above ground. - ANS✅✅basidiocarp
,A 10^-1 dilution is performed 5 times on the same sample as mathematically depicted above. To find
the cumulative dilution, each dilution should be _____ together. The cumulative dilution therefore
equals ______. - ANS✅✅multiplied; 1*10^-5
What technique is most likely to be used for sterilizing a vitamin solution that is added to culture
media? - ANS✅✅***
In general, when performing spread plates, ______ mL of cell suspension is added to the plate to
prevent the formation of a microbial _______. Adding more than 1 mL of cell suspension to an agar
plate will result in a ______. Adding less than 1 mL of cell suspension to an agar plate will result in a
______. - ANS✅✅0.1
lawn
concentration
dilution
A limitation of microscopic methods for counting cells is that - ANS✅✅microscopic cells counts
enumerate cells that were both living and dead at the time of sampling
A bacterium adapted to life in hot environments would be more likely to have - ANS✅✅cell
membranes with a greater number of saturated fatty acids
Which two domains of life form a monophyletic group (aka: are most closely related)? -
ANS✅✅Archaea
Eukaryotes
Correctly order the steps in Koch's Postulates - ANS✅✅1. The microorganism must be found in
abundance in all organisms suffering from the disease, but should not be found in healthy organisms
2. The microorganism must be isolated from a diseased organism and grown in pure culture.
3. The cultured microorganism should cause disease when introduced into a healthy organism
4. The microorganism must be reisolated from the inoculated, diseased experimental host and
identified as being identical to the original specific causative agent.
Which compound is a constituent of both pseudomurein and peptidoglycan? - ANS✅✅N-
Acetylglucosamine
, Which kind of media contains highly nutritious materials or specific compounds that enable certain
kinds of microbes to grow? - ANS✅✅Enriched media
Which kinds of media contains a dye or other indicator that responds to metabolic reactions during
growth to identify a specific organism? - ANS✅✅Differential
Which kind of media is used to culture fastidious microbes? - ANS✅✅Enriched media
Sabouraud Glucose Agar with chloramphenicol is used to culture fungi. The chloramphenicol is used
to inhibit the growth of bacteria. Which of the statements below correctly describes this media? -
ANS✅✅- This media selects for fungi
- This media selects against bacteria
If 1 mL of culture is transferred to 99 mL of sterile media, and then 1 mL of that dilution is
transferred to 9 mL of sterile media, and finally 0.1 mL of that dilution is transferred to a plate, what
is the final dilution? - ANS✅✅1*10^-4
(1/100)*(1/10)*(0.1) = 1e-4
If 1 mL of culture is transferred to 99 mL of sterile media, and then 0.1 of that dilution is transferred
to 9.9 mL of sterile media, and finally of that dilution is transferred to a plate, what is the final
dilution? - ANS✅✅1*10^-3
There are so many microbes is a single mL of culture, it is very difficult to perform one dilution to
produce countable cells. Microbiologists need to perform a dilution series, where multiple dilutions
are performed in sequence to arrive at the correct dilution.
Dilutions are cumulative. Multiply the series of dilutions together to find the final dilution value.
If 2 serial dilutions are performed, each with a dilution of 0.1, what is the cumulative dilution? -
ANS✅✅1*10^-2
0.1 * 0.1 = 0.01
