Microbiology Lab Exam 1 Questions
and Answers 100% Pass
What is the purpose of a streak plate? - ✔✔1) To separate cells so that they
grow to form isolated colonies 2) To confirm if a culture is a pure colony or
mixed 3) To confirm is there is contamination in your culture
What is a colony? - ✔✔Areas of growth that arise from a single cell.
How do colonies form? - ✔✔They are formed by spreading out cells. Cells
are spread and reproduce over and over again through bionary fission
until visable mass of cells appear.
What is a pure culture? - ✔✔Culture containing only one type of organism
What kind of media are colonies able to form on? - ✔✔agar slant, broth
media, agar plate
1
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,When is a agar slant used? Pros & cons - ✔✔1) Smaller amount of surface
area prevents the media from drying out too quickly 2) useful for medium
term storage 3) viable for a couple of months if stored properly
What are the 4 criteria for labeling a microbial culture? - ✔✔1) initials or
name AND group number
2) date
3) growth media type
4) culture name or source of inoculum
Describe bacillus (bacilli) morphology - ✔✔rod shaped cells, longer than
wide, sausage like, can use rod or bacillus
describe coccus morphology - ✔✔cells are ball shaped or spherical
Describe coccobacillus morphology - ✔✔elongated spheres- not quite
spherical, but not clearly a rod. Tends to occur in species which are
normally rod-shaped during rapid growth.
Describe spirillum morphology - ✔✔Helical, loose or tight coils. Look like
wavy lines - morphology has no arrangement
2
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,Describe filamentous morphology - ✔✔Long elongated cells. Look like a
tangled mass of branched filaments- no arrangement
Describe vibrio morphology - ✔✔A curved rod or comma shape
What does No arrangement mean? - ✔✔Single cells, ungrouped. Not all
cells have an arrangement
What is the cell arrangement Diplococci/Diplobacilli - ✔✔Pairs of cells.
Diplococci are pairs of cocci, diplobacilli are pairs of rods
What is the cell arrangement Streptococci/Streptobacilli? - ✔✔Chains of
cells. Streptococci are chains of cocci, streptobacilli are chains of rods
What is the call arrangement staphylococcus? - ✔✔Irregular clusters of
cells- like bunches of grapes.
What is the cell arrangement of tetrads? - ✔✔Sets of 4 regularly arranged
cells
What is the cell arrangement of palisade? - ✔✔Bacilli (usually 2-4 cells)
arranged side by side. Columns or "V-forms"
3
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, What genus is an acid fast bacteria? - ✔✔Mycobacterium tuberculosis
What genus is an capsule former? - ✔✔Klebsiella pneumoniae
What is a simple stain? - ✔✔Involves only one dye to make cells more
visable. Involves methylene blue or crystal voilet.
What is a complex stain? - ✔✔Two or more stains. Allow the differentiation
of cell types or cell structures. (can be called differential stain)
What is a differential stain? - ✔✔Another name for complex stain. Allow us
to see the differences between different cell types or cell structures. Uses at
least two different stains.
What is a negative stain? - ✔✔Leaves cell or a cell structure unstained
while the background is stained. No heat fixing. Used to determine cell
shapes more accurately or to see structures which may be unable to accept
dyes, or which are adversely affected by heat fixation (capsules)
What does water soluble mean? - ✔✔Bacteria that produce colorful
pigments and color spreads into the agar
4
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and Answers 100% Pass
What is the purpose of a streak plate? - ✔✔1) To separate cells so that they
grow to form isolated colonies 2) To confirm if a culture is a pure colony or
mixed 3) To confirm is there is contamination in your culture
What is a colony? - ✔✔Areas of growth that arise from a single cell.
How do colonies form? - ✔✔They are formed by spreading out cells. Cells
are spread and reproduce over and over again through bionary fission
until visable mass of cells appear.
What is a pure culture? - ✔✔Culture containing only one type of organism
What kind of media are colonies able to form on? - ✔✔agar slant, broth
media, agar plate
1
100% Pass Guarantee Katelyn Whitman, All Rights
,When is a agar slant used? Pros & cons - ✔✔1) Smaller amount of surface
area prevents the media from drying out too quickly 2) useful for medium
term storage 3) viable for a couple of months if stored properly
What are the 4 criteria for labeling a microbial culture? - ✔✔1) initials or
name AND group number
2) date
3) growth media type
4) culture name or source of inoculum
Describe bacillus (bacilli) morphology - ✔✔rod shaped cells, longer than
wide, sausage like, can use rod or bacillus
describe coccus morphology - ✔✔cells are ball shaped or spherical
Describe coccobacillus morphology - ✔✔elongated spheres- not quite
spherical, but not clearly a rod. Tends to occur in species which are
normally rod-shaped during rapid growth.
Describe spirillum morphology - ✔✔Helical, loose or tight coils. Look like
wavy lines - morphology has no arrangement
2
100% Pass Guarantee Katelyn Whitman, All Rights
,Describe filamentous morphology - ✔✔Long elongated cells. Look like a
tangled mass of branched filaments- no arrangement
Describe vibrio morphology - ✔✔A curved rod or comma shape
What does No arrangement mean? - ✔✔Single cells, ungrouped. Not all
cells have an arrangement
What is the cell arrangement Diplococci/Diplobacilli - ✔✔Pairs of cells.
Diplococci are pairs of cocci, diplobacilli are pairs of rods
What is the cell arrangement Streptococci/Streptobacilli? - ✔✔Chains of
cells. Streptococci are chains of cocci, streptobacilli are chains of rods
What is the call arrangement staphylococcus? - ✔✔Irregular clusters of
cells- like bunches of grapes.
What is the cell arrangement of tetrads? - ✔✔Sets of 4 regularly arranged
cells
What is the cell arrangement of palisade? - ✔✔Bacilli (usually 2-4 cells)
arranged side by side. Columns or "V-forms"
3
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, What genus is an acid fast bacteria? - ✔✔Mycobacterium tuberculosis
What genus is an capsule former? - ✔✔Klebsiella pneumoniae
What is a simple stain? - ✔✔Involves only one dye to make cells more
visable. Involves methylene blue or crystal voilet.
What is a complex stain? - ✔✔Two or more stains. Allow the differentiation
of cell types or cell structures. (can be called differential stain)
What is a differential stain? - ✔✔Another name for complex stain. Allow us
to see the differences between different cell types or cell structures. Uses at
least two different stains.
What is a negative stain? - ✔✔Leaves cell or a cell structure unstained
while the background is stained. No heat fixing. Used to determine cell
shapes more accurately or to see structures which may be unable to accept
dyes, or which are adversely affected by heat fixation (capsules)
What does water soluble mean? - ✔✔Bacteria that produce colorful
pigments and color spreads into the agar
4
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