BIOS 242 Week 1 iLab: Exploring the Microbiology Lab
iLab: Exploring the Microbiology Lab
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Section 1 Lab Safety
1. There are
... [Show More] four safety equipment items that a lab should have. Identify two of these four items. (2 pts.)
Eye wash and shower.
2. Identify one of the three ways to keep your work area safe. (1 pt.)
Always keep workspace free of any unnecessary objects and materials
3. There are five recommendations for dressing properly in a lab environment. Name two of these recommendations. (2 pt.)
Wear proper clothing – such as close-toed shoes and no loose or baggy clothing. Also, limit jewelry or dangly items such as bracelets.
4. There are several safety tips to protect one’s mucous membranes and broken skin. Identify one of the recommended tips. (1 pt.)
Do not insert eye contacts in the lab.
5. When working in a microbiology lab, it is important to contain spills and discard materials properly. Describe how a spill should be cleaned up safely in a microbiology lab. (3 pts.)
1.) Wear a lab coat, disposable gloves, safety glasses or a face shield, and if needed, approved respiratory equipment.
2.) Soak a paper towel(s) in an appropriate disinfectant (70% ethanol or fresh 10% bleach solution) and place around the spill area.
3.) Working from the outer edges into the center, clean the spill area with fresh towels soaked in the disinfectant. Be sure to decontaminate any areas or surfaces that you suspect may have been affected by the spill. Allow 10 minutes contact time.
4.) Place the paper towels and gloves into a biohazard bag and autoclave these materials to sterilize them.
5.) Dispose of any contaminated clothing properly.
6. Describe the procedures that one must do before leaving the lab. (3 pts.)
1.) Before leaving the lab, make sure all items have been returned to their appropriate location.
2.) After your work area is clear, wipe thoroughly with antimicrobial soap before leaving the lab.
3.) Do not remove any item from the lab unless you have been directed to do so by the lab instructor.
Section 2 Biochemical Tests
7. How do you know that no contamination occurred when you inoculated your culture? (1 pt.)
There would be no unexpected growths.
8. If the biochemical test requires an incubation of 24 hours, what do you need to do? (1 pt.)
Ensure it has been a full 24 hours before observing.
9. If your biochemical test requires that a reagent is added, which tool do you need to use? (1 pt.)
Separatory funnels
10. There are two ways to record the results of a biochemical test. Watch the video found in the Recording Results tutorial. What was the result of the acid from glucose test? (1 pt.)
The culture turned yellow indicating a positive test.
11. An important tool available in the Virtual Unknown program is the Identification Matrix. From the portion of the identification matrix shown in the Identifying Bacteria tutorial, identify at least one bacterium that has a positive result to the arabinose fermentation test. (1 pt.)
Cedecea neteri
Section 3: Reference Books
12. The first step of identification of an unknown bacterium is determining if the bacterium is gram negative or gram positive. (6 pts.)
Using the information found in the Gram Negative Enteric Baccilli and Gram Positive Cocci Reference books, complete the following table:
Bacteria Gram positive or negative? Locations most frequently found Identify at least one illness that bacteria can cause
Staphlococcus aureus
Gram Positive
Skin, Hair
Cellulitis
Proteus vulgaris
Gram Negative
Water, Fecal Matter
Urinary Tract Infections
The following questions, which focus on the Dulcitol Fermentation Test, will help you explore these resources.
13. What is the purpose of the dulcitol fermentation test? (1 pt.)
The purpose of the dulcitol fermentation test is to see if the microbe would ferment the carbohydrate (dulcitol) as a carbon source.
14. Which medium is used to perform the dulcitol fermentation test? What is the indicator used in this medium? (2 pts.)
The medium used is phenol red dulcitol broth. Phenol red is a pH indicator which is red when neutral, but turns yellow with a less than 6.8 pH level, and a hot pink or magenta color with a pH level greater than 8.4.
15. After incubating the inoculated medium for 24 hours, the medium is yellow. Can the bacterium that you tested ferment dulcitol? (1 pt.)
Yes, the color change from red to yellow indicates a positive acidic reaction.
16. Medium containing phenol red will be yellow when the pH is less than 6.8. Why would the medium change from a neutral pH to an acidic pH? (3 pts)
The medium would change from a neutral pH to an acidic pH when the pH value decreases. [Show Less]