BIO 171 Lab Exam 3 (L3) | Microbiology: Key Concepts and Techniques
| Actual Q&A with Rationale (BIO171 Lab Exam 3) | Portage Learning
Online
Score for this quiz: 30 out of 30 (100%)
Question 1 (2.5 pts)
List the four main steps used to prepare a WET mount, and indicate which (if any) step
is optional.
1. Clean slide with 70% ethanol
• Circle area on slide with a wax/hydrophobic pen
• Apply organism to slide
• View under microscope
Note: No step is optional for a wet mount.
Rationale: All steps are necessary to ensure a clean, contained, and observable sample.
The hydrophobic pen keeps the liquid confined; cleaning prevents contamination.
Question 2 (2.5 pts)
Why is it important to first clean your slide before applying your sample?
To remove any unwanted contaminants from the slide; otherwise it may be difficult to
distinguish between the pathogen of interest and a contaminant.
Rationale: Contaminants can cause false results or obscure the organism being
observed.
Question 3 (2.5 pts)
When performing a wet mount technique, what is the advantage of using a wax or
hydrophobic pen?
It creates a hydrophobic barrier that keeps the water within the circle so it does not
spill off the slide.
Rationale: The circle confines the liquid, preventing it from spreading and allowing
better focusing.
| Actual Q&A with Rationale (BIO171 Lab Exam 3) | Portage Learning
Online
Score for this quiz: 30 out of 30 (100%)
Question 1 (2.5 pts)
List the four main steps used to prepare a WET mount, and indicate which (if any) step
is optional.
1. Clean slide with 70% ethanol
• Circle area on slide with a wax/hydrophobic pen
• Apply organism to slide
• View under microscope
Note: No step is optional for a wet mount.
Rationale: All steps are necessary to ensure a clean, contained, and observable sample.
The hydrophobic pen keeps the liquid confined; cleaning prevents contamination.
Question 2 (2.5 pts)
Why is it important to first clean your slide before applying your sample?
To remove any unwanted contaminants from the slide; otherwise it may be difficult to
distinguish between the pathogen of interest and a contaminant.
Rationale: Contaminants can cause false results or obscure the organism being
observed.
Question 3 (2.5 pts)
When performing a wet mount technique, what is the advantage of using a wax or
hydrophobic pen?
It creates a hydrophobic barrier that keeps the water within the circle so it does not
spill off the slide.
Rationale: The circle confines the liquid, preventing it from spreading and allowing
better focusing.
