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microbiology lab final exam Questions and
Answers 100% Pass
Which staining technique is used to determine the thickness of the peptidoglycan layer based on the cell
wall composition? - ✔✔Gram stain
Where would you properly dispose of the following items? - ✔✔Contaminated slides: Slide trays on
student benches
Pipettes: Nalgene buckets on student benches
Used test tubes: Trash cart at front of lab
Uncontaminated broken glass: Broken glass box at front of lab (and notify the TA!)
When are open toed-shoes and shorts allowed in the microbiology labs? - ✔✔Never
What do you use to clean the ocular lenses and objective lenses on your microscope? - ✔✔Lens cleaner
and lens paper
________________________ microscopy is used to view dead, stained microorganisms, and
________________________ microscopy is used to view live, unstained microorganisms - ✔✔Brightfield,
phase-contrast
What is the purpose of isolation streaks on your environmental isolate? - ✔✔To purify one species of
bacteria
In microscopy, what are the three main factors to obtain a good image? - ✔✔Magnification, resolution,
and contrast
Created by Katelyn Whitman © 2025, All Rights Reserved. 100% PASS GUARANTEE
, 2|Page
Which objective lens is used with immersion oil? - ✔✔100X objective lens
When you first enter the lab and again before you leave the lab, what are two things that you should
always do? - ✔✔Wash your hands and wipe down the lab bench with QT solution
In Exercise 1 Part 2 Phase-Contrast Microscopy, ______________ ______________ was used to visualize
bacteria at 1000x total magnification with oil immersion. - ✔✔Bacillus megaterium
Which of the following is a growth streak? - ✔✔perfect up down streak
______________ ______________ is the positive control organism for the capsule stain. - ✔✔Klebsiella
pneumoniae
With regard to staining techniques used in this lab, what is the definition of a control organism? - ✔✔A
control organism is known to have a positive or negative result for a specific staining technique and is
used as a comparison to determine the staining result of an unknown bacteria
When differentially staining bacterial cells, what is the purpose of the steaming step? - ✔✔Endospore
stain: Drives the primary stain into keratin proteins
Capsule stain: The steaming step is not used in this staining technique
Gram stain: The steaming step is not used in this staining technique
Based on the following image, where is the appropriate place to label a Petri plate? - ✔✔Along the side of
the bottom plate
How do bacteria benefit from the production of endospores? - ✔✔Endospores allow bacteria to survive
stressful environmental conditions
When staining bacterial cells, what is the purpose of a mordant? - ✔✔The mordant and the primary stain
form an insoluble complex that is attached to a substrate of interest
Created by Katelyn Whitman © 2025, All Rights Reserved. 100% PASS GUARANTEE
microbiology lab final exam Questions and
Answers 100% Pass
Which staining technique is used to determine the thickness of the peptidoglycan layer based on the cell
wall composition? - ✔✔Gram stain
Where would you properly dispose of the following items? - ✔✔Contaminated slides: Slide trays on
student benches
Pipettes: Nalgene buckets on student benches
Used test tubes: Trash cart at front of lab
Uncontaminated broken glass: Broken glass box at front of lab (and notify the TA!)
When are open toed-shoes and shorts allowed in the microbiology labs? - ✔✔Never
What do you use to clean the ocular lenses and objective lenses on your microscope? - ✔✔Lens cleaner
and lens paper
________________________ microscopy is used to view dead, stained microorganisms, and
________________________ microscopy is used to view live, unstained microorganisms - ✔✔Brightfield,
phase-contrast
What is the purpose of isolation streaks on your environmental isolate? - ✔✔To purify one species of
bacteria
In microscopy, what are the three main factors to obtain a good image? - ✔✔Magnification, resolution,
and contrast
Created by Katelyn Whitman © 2025, All Rights Reserved. 100% PASS GUARANTEE
, 2|Page
Which objective lens is used with immersion oil? - ✔✔100X objective lens
When you first enter the lab and again before you leave the lab, what are two things that you should
always do? - ✔✔Wash your hands and wipe down the lab bench with QT solution
In Exercise 1 Part 2 Phase-Contrast Microscopy, ______________ ______________ was used to visualize
bacteria at 1000x total magnification with oil immersion. - ✔✔Bacillus megaterium
Which of the following is a growth streak? - ✔✔perfect up down streak
______________ ______________ is the positive control organism for the capsule stain. - ✔✔Klebsiella
pneumoniae
With regard to staining techniques used in this lab, what is the definition of a control organism? - ✔✔A
control organism is known to have a positive or negative result for a specific staining technique and is
used as a comparison to determine the staining result of an unknown bacteria
When differentially staining bacterial cells, what is the purpose of the steaming step? - ✔✔Endospore
stain: Drives the primary stain into keratin proteins
Capsule stain: The steaming step is not used in this staining technique
Gram stain: The steaming step is not used in this staining technique
Based on the following image, where is the appropriate place to label a Petri plate? - ✔✔Along the side of
the bottom plate
How do bacteria benefit from the production of endospores? - ✔✔Endospores allow bacteria to survive
stressful environmental conditions
When staining bacterial cells, what is the purpose of a mordant? - ✔✔The mordant and the primary stain
form an insoluble complex that is attached to a substrate of interest
Created by Katelyn Whitman © 2025, All Rights Reserved. 100% PASS GUARANTEE
