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Student Name Alissa Obryan Student ID 271304 Lesson Aseptic Technique and Culturing Microbes Institution Coastal Carolina Community College Session 275-02W Summer 2023 Course Microbiology 275-02W Summer 2023 Instructor Marie Smith
Final Report
Test Your Knowledge
Microbiology 275-02W Summer 2023
Aseptic Technique and Culturing Microbes
True False
Identify each statement as true or false.
1
Aseptic techniques are designed to prevent the spread of microorganisms beyond the intended working environment.
Open tubes and vials should be tilted away from the mouth and nose.
Media containers should be stored away from children and pets.
2
The caps and lids of media containers should be placed on countertops when working with cultures.
Plates should be incubated agar side down.
Work surfaces should be sterilized with soap and water.
Exploration
Liquid media used to increase the number of microorganisms.
Solid media used to isolate microbes.
Normal flora bacteria used for studies involving osmotic pressure, antibiotic resistance, and biofilms.
Clump of genetically identical microorganisms.
Single-celled fungi used for studies involving fermentation, genetics, and aging.
Instrument used for spreading microorganisms across a streak plate.
Match each term to the best description.
Broth
Agar plate
Staphylococcus epidermidis
Colony forming unit
Saccharomyces cerevisiae
Inoculation loop
Agar plates should be labeled on the _____.
lid
bottom
side
All of the above
1 2 3 4 5 6
Because this helps to keep a clean or aseptic environment which prevents the growing microbes from being contaminated, it also helps with erasing most or all bacteria from the surface for a clean and safe environment. Just like after you flush the toilet and touch the toilet seat, you are picking up bacteria which is why there is a proper way to wash your hands to get rid of those germs so you won't get sick.
What is the purpose of wiping down your work area with bleach before and after an experiment?
I wore my safety goggles, gloves, apron, and face mask, washed my hands properly, and disinfected when needed to keep myself and my microbes safe.
List five safety precautions you used to protect yourself while culturing microbes.
the broth's purpose is to grow a wide amount of microbes in a small place. The small place in this case would be the petri dish.
What is the purpose of a broth in a microbiology laboratory?
My S. cerevisiae showed signs of flocculent microbial growth in the bottom of the tube by the time 48 hours passed and my S. epidermis had very few growth specks floating in the tube. Still, they were identifiable enough to know that it was growth. My E. coli tube had a change of color as well as my S. epidermis. I believe that my S. epidermis and E. coli could have produced more growth if it would have incubated for a longer time and if it was placed in a real incubation machine and not a cabinet.
Did each of your cultures develop at the same rate? Why might your incubation environment favor one microbe over another?
Photo 1: Escherichia Coli Broth
Photo 2: Staphylococcus Epidermidis Broth
Data Table 1: Broth Culture Results
Exercise 2
Microbe Description
Escherichia coli
Staphylococcus epidermidis
Saccharomyces cerevisiae
My E. coli tube had a change of color, clear broth
my S. epidermis had very few growth specks floating in the tube. Clear broth with yellowish tint
microbial growth in the bottom of the tube and cloudy in color.
Colonies are populations of bacteria that populate from a single cell. It relates to a bacterial cell because it makes bacteria easier to see and shows how they are able to develop and grow.
What is a colony and how does a colony relate to a bacterial cell? Why are colonies important in the study of microbiology?
bacteria is easier to see on a plate because it is not inside of a liquid but rather grown on agar. with the broth being a liquid and not a jelly-like substance, we cannot see exact shapes of the bacteria.
Are bacteria easier to observe on a plate or in a broth? How do the bacteria look on the plate as compared to the broth?
Photo 5: Staphylococcus Epidermidis Plate
Photo 6: Saccharomyces Cerevisiae Plate
Aseptic technique includes _____.
working quickly and efficiently around open media containers
not talking or breathing over open media containers
washing hands before and after working with media
All of the above
All equipment and work surfaces should be cleaned with a bleach solution after contacting microbe cultures.
True
False
Tryptic Soy Agar (TSA) is a _____ media.
general purpose liquid
selective liquid
general purpose solid
None of the above
Streak plating is performed by pouring broth onto agar plates.
True
False
_____ is a common, harmless microbe used in laboratory studies.
Escherichia coli
Saccharomyces cerevisiae
Staphylococcus epidermidis
All of the above
Extension Questions
When transferring microbes from a broth to a plate, the inoculation loop should be sterilized _____.
before placing in broth
after spreading microbes on the agar surface
prior to disposal
All of the above
Turbidity and flocculence are indicators of microbial growth in liquid media.
True
False
A pure plated culture should exhibit colony forming units with two or more morphologies.
True
False
After the colony forms, you can see the differences in the shapes because no petri dish with bacteria will be the same. Using a streak plate and using sterilization can help the student create a pure culture.
A new microbiology student failed to properly sterilize the pipet between creating E. coli and S. epidermidis cultures from the tablets in the lab kit. How would this mistake be recognized when the mixed culture is streak plated? How could the student create a pure culture from the mixed culture streak plate?
