“Lab 2 Culturing & Aseptic Technique BIO250L”
Student Name: Click here to enter text.
Access Code (located on the underside of the lid of your lab kit): Click here to enter text.
“Pre-Lab Questions”
- Proper aseptic technique is crucial to ensuring growth of pure bacterial colonies. What is one
experimental way you can test your practices to confirm that you are using proper aseptic
technique?
Click here to enter text. - In a laboratory setting, what are three ways you can properly sterilize culturing equipment?
a. Click here to enter text.
b. Click here to enter text.
c. Click here to enter text. - For each inoculation tool, give one scenario in which use of that tool would be appropriate.
Click here to enter text. - Why don’t microorganisms in cultures exhibit constant exponential growth? What are some
steps you could take to extend the lifespan of a microbial culture?
Click here to enter text. - Using a textbook or a reputable online source, describe how lab cultures are maintained in a
continual pattern of growth. Focus particularly on those used in biotechnology, such as E. coli,
“Lab 2 Culturing & Aseptic Technique BIO250L”
which is used to make human insulin.
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- Which of these has a constant growth pattern: an open system or a closed system?
Click here to enter text. - A human patient represents what kind of system for bacterial infections?
Click here to enter text. - You’re a physician trying to isolate bacterial colonies from the human gut in attempt to diagnose
a gastrointestinal infection. You streak your sample on a growth media containing glucose,
amino acids, and salts that contain both sulfur and phosphorous with a pH of 7. You incubate
the plates in aerobic conditions at 37 ˚C for three days, at which point you can see clear
bacterial colonies forming on the plate. Would you feel confident in stating that you had
successfully cultured all the bacteria from your gut sample? Why or why not?
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“EXPERIMENT 1: Agar Plate Preparation and Bacterial Inoculation
Data Tables
Table 1: Experiment 1 Colony Growth
Growth
Plate Number
Source
(Color, Amount, Shape, etc.)
1
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2
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3
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4
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5
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“Lab 2 Culturing & Aseptic Technique BIO250L”
Post-Lab Questions
- Do some research and try to identify one to three types of microbes cultured on your plates.
Using any resources available to you (i.e., a textbook or internet sources such as the CDC
website), look up what bacteria are usually found on the areas from which you obtained your
samples and the morphological characteristics of their colonies. Describe what morphological
traits (i.e., size, shape, arrangement, color, margin, etc.) led to your hypothesized species
identification. Be as specific as possible in the microbe type.
Click here to enter text. - For the colonies hypothesized in Question 1, specify which plate and source the microbes came
from. Are you surprised to find this type of microbe on this surface?
Click here to enter text. - Looking at your control, did you perform proper aseptic technique or were your plates
contaminated? If contamination did occur, list the possible sources and how you can prevent
contamination in the future.
Click here to enter text. - Was there a large risk for airborne contamination of your experimental plates? Based on the
colonies that grew on your plates, do you think any of your experiment plates received airborne
contamination?
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“Lab 2 Culturing & Aseptic Technique BIO250L”
Insert a photo of your plates after incubation. Include your name and access code handwritten in the
background of your photo.
“EXPERIMENT 2: Bacterial Transfer to a Stab Tube and an Agar Plate
Data Tables
Table 2: Initial Reserved Plate Colony Growth Observations
“Lab 2 Culturing & Aseptic Technique BIO250L”
Plate Sample
Appearance (morphology, etc.)
1
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2
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3
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Table 3: Final Plate and Stab Tube Growth Observations
Sample
Form
Growth (Yes
or No)
Same Appearance as
Initial Plate (Yes or
No)
Successful
Transfer? (Yes or
No)
Select one:
1
Plate
Select one:
Select one:
1
Select one:
Stab Tube
Select one:
Select one:
Select one:
2
Plate
Select one:
Select one:
2
Select one:
Stab Tube
Select one:
Select one:
Select one:
3
Plate
Select one:
Select one:
3
Select one:
Stab Tube
Select one:
Select one:
Control
Select one:
Plate
Select one:
Select one:
Control Stab Tube
Select one:
Select one:
Select one:
Post-Lab Questions
- Were all of your colony transfers successful? Explain what could have been the cause of any
unsuccessful transfers.
Click here to enter text. - Did you have any growth that was different in appearance from the initial plates? What might
account for any differences in growth on the transfer plate/tube?
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“Lab 2 Culturing & Aseptic Technique BIO250L”
- Describe why an unsuccessful transfer or growth of the transfer plate/tube differing from the
initial plates would be a problem if this experiment were placed in a larger context (i.e., only one
step in a longer experiment).
Click here to enter text. - Do some research and describe two or three scenarios in which it would be preferable to use a
stab tube vs. a growth plate. (Hint: What do bacteria use to help them move? Can motility be
used to help identify many medically important pathogenic bacteria such as the
Enterobacteriaceae?)
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Insert a photo of your plates and stab tubes after incubation. Include your name and access code
handwritten in the background of your photo.
