Microbiology Lab Exam # 1 Questions
and Answers 100% Pass
Considering the cultures used to inoculate each medium in this exercise,
how many different microbial types should you expect to see in/on each
medium? (1.4) - ✔✔You should only have 1 if using good sterile technique.
A successful aseptic transfer will have only micrococcus lutes growth- this
would be a pure culture
You were asked to describe differences in appearance of growth in each
culture, if present. In which medium was this the most difficult to
determine? What made it difficult? (1.4) - ✔✔More difficult to see in broth
because you can only see if growth occurred on the top or bottom etc.
Better in slant because you can observe different growth patterns.
1
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,Which medium was most difficult for you to transfer from? Which medium
was most difficult for you to inoculate? Why? (1.4) - ✔✔Most people don't
like working with slants (solid)
If you got growth on sterile NA and NB slant rubes, why? (1.4) -
✔✔Possible contamination include not heating the loop to orange-hot, not
holding the open tubes on an angle, and/or placing the cap on the table
surface during the process.
Did you notice a difference in density (turbidity) of growth in NB tubes
inoculated from NB and NA slants? Possible reasons?( 1.4) - ✔✔Generally,
more cells are transferred from growth on a solid medium than from a
broth culture. Therefore, broth cultures made from growth on a solid
medium will show greater turbidity than those inoculated from a broth
culture.
Did you notice a difference in density of growth on NA slants inoculated
from NA slants and NB? (1.4) - ✔✔Generally there will be denser growth
on the slant inoculated from the NA slant, because more cells are
transferred from solid medium than broth.
2
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,Pure culture (1.4) - ✔✔When a culture ( a medium that contains living
microbes) contains a single species.
Broths (1.4) - ✔✔A medium used to grow microbes when fresh cultures or
large numbers of cells are required. Used for ID.
Agar Slant (1.4) - ✔✔A type of medium used to grow stock cultures that
can be refrigerated after incubation and maintained for several weeks.
Plated Media (1.4) - ✔✔A type of medium used for obtaining isolation of
species, differential testing, and quantifying bacterial densities.
Inoculating loops (1.4) - ✔✔An instrument used to inoculate a medium.
Inoculation (1.4) - ✔✔To introduce (cells or organisms) into a culture
medium.
Using a pencil, draw a quadrant streak (1.5) - ✔✔Should look like this. You
should also rotate a little less than 90 Degrees each streak, and heat the
loop so you can get good results. Also, let the loop cool!!
Mixed Culture (1.5) - ✔✔A microbial culture consisting of two or more
species.
3
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, What is generally the first step in identifying a microbial organism? (1.5) -
✔✔Obtaining isolations of Individual colonies. The technique we used in
class was the isolation technique- the streak plate. Cells that have been
sufficiently isolated will grow into colonies, consisting only of the original
cell type.
Colonies (1.5) - ✔✔Individual microbial cell type. They can also form from
a pair, chain, or cluster of cells.
Colony Forming Unit (CFU) (1.5) - ✔✔A more correct description of the
colony origin
Zigzag Inoculation (1.5) - ✔✔A type of inoculation pattern used to when
the sample does not have a high enough cell density.
Quadrant streak technique: (1.5)
- how much space should you try to use?
- describe what each of the quadrants should look like
4
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and Answers 100% Pass
Considering the cultures used to inoculate each medium in this exercise,
how many different microbial types should you expect to see in/on each
medium? (1.4) - ✔✔You should only have 1 if using good sterile technique.
A successful aseptic transfer will have only micrococcus lutes growth- this
would be a pure culture
You were asked to describe differences in appearance of growth in each
culture, if present. In which medium was this the most difficult to
determine? What made it difficult? (1.4) - ✔✔More difficult to see in broth
because you can only see if growth occurred on the top or bottom etc.
Better in slant because you can observe different growth patterns.
1
100% Pass Guarantee Katelyn Whitman, All Rights
,Which medium was most difficult for you to transfer from? Which medium
was most difficult for you to inoculate? Why? (1.4) - ✔✔Most people don't
like working with slants (solid)
If you got growth on sterile NA and NB slant rubes, why? (1.4) -
✔✔Possible contamination include not heating the loop to orange-hot, not
holding the open tubes on an angle, and/or placing the cap on the table
surface during the process.
Did you notice a difference in density (turbidity) of growth in NB tubes
inoculated from NB and NA slants? Possible reasons?( 1.4) - ✔✔Generally,
more cells are transferred from growth on a solid medium than from a
broth culture. Therefore, broth cultures made from growth on a solid
medium will show greater turbidity than those inoculated from a broth
culture.
Did you notice a difference in density of growth on NA slants inoculated
from NA slants and NB? (1.4) - ✔✔Generally there will be denser growth
on the slant inoculated from the NA slant, because more cells are
transferred from solid medium than broth.
2
100% Pass Guarantee Katelyn Whitman, All Rights
,Pure culture (1.4) - ✔✔When a culture ( a medium that contains living
microbes) contains a single species.
Broths (1.4) - ✔✔A medium used to grow microbes when fresh cultures or
large numbers of cells are required. Used for ID.
Agar Slant (1.4) - ✔✔A type of medium used to grow stock cultures that
can be refrigerated after incubation and maintained for several weeks.
Plated Media (1.4) - ✔✔A type of medium used for obtaining isolation of
species, differential testing, and quantifying bacterial densities.
Inoculating loops (1.4) - ✔✔An instrument used to inoculate a medium.
Inoculation (1.4) - ✔✔To introduce (cells or organisms) into a culture
medium.
Using a pencil, draw a quadrant streak (1.5) - ✔✔Should look like this. You
should also rotate a little less than 90 Degrees each streak, and heat the
loop so you can get good results. Also, let the loop cool!!
Mixed Culture (1.5) - ✔✔A microbial culture consisting of two or more
species.
3
100% Pass Guarantee Katelyn Whitman, All Rights
, What is generally the first step in identifying a microbial organism? (1.5) -
✔✔Obtaining isolations of Individual colonies. The technique we used in
class was the isolation technique- the streak plate. Cells that have been
sufficiently isolated will grow into colonies, consisting only of the original
cell type.
Colonies (1.5) - ✔✔Individual microbial cell type. They can also form from
a pair, chain, or cluster of cells.
Colony Forming Unit (CFU) (1.5) - ✔✔A more correct description of the
colony origin
Zigzag Inoculation (1.5) - ✔✔A type of inoculation pattern used to when
the sample does not have a high enough cell density.
Quadrant streak technique: (1.5)
- how much space should you try to use?
- describe what each of the quadrants should look like
4
100% Pass Guarantee Katelyn Whitman, All Rights
