SERIES MICROBIOLOGY LAB FINAL EXAM COMPLETE QUESTIONS AND CORRECT ANSWERS | GRADED AND THE LATEST SERIES

2025-2026 SERIES
MICROBIOLOGY LAB FINAL EXAM COMPLETE
QUESTIONS AND CORRECT ANSWERS | GRADED
AND THE LATEST SERIES
Which staining technique is used to determine the thickness of the peptidoglycan

layer based on the cell wall composition?


Ans: Gram stain


Question: Where would you properly dispose of the following items?


Ans: 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!)


Question: When are open toed-shoes and shorts allowed in the microbiology

labs?


Ans: Never


Question: What do you use to clean the ocular lenses and objective lenses on

your microscope?


Ans: Lens cleaner and lens paper

, 2025-2026 SERIES
Question: ________________________ microscopy is used to view dead,

stained microorganisms, and ________________________ microscopy is used to

view live, unstained microorganisms


Ans: Brightfield, phase-contrast


Question: What is the purpose of isolation streaks on your environmental

isolate?


Ans: To purify one species of bacteria


Question: In microscopy, what are the three main factors to obtain a good

image?


Ans: Magnification, resolution, and contrast


Question: Which objective lens is used with immersion oil?


Ans: 100X objective lens


Question: When you first enter the lab and again before you leave the lab,

what are two things that you should always do?


Ans: Wash your hands and wipe down the lab bench with QT solution


Question: In Exercise 1 Part 2 Phase-Contrast Microscopy, ______________

______________ was used to visualize bacteria at 1000x total magnification

with oil immersion.

, 2025-2026 SERIES
Ans: Bacillus megaterium


Question: Which of the following is a growth streak?


Ans: perfect up down streak


Question: ______________ ______________ is the positive control organism

for the capsule stain.


Ans: Klebsiella pneumoniae


Question: With regard to staining techniques used in this lab, what is the

definition of a control organism?


Ans: 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


Question: When differentially staining bacterial cells, what is the purpose of the

steaming step?


Ans: 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


Question: Based on the following image, where is the appropriate place to

label a Petri plate?