Micro biology 260
Dr. Timm
Review
Lab quiz material
Microscope
How is the magnification power of microscope calculated
What does the working distance refer to?
Know the parts of a microscope
What is the purpose of oil on the microscope slide.
What is the procedure to clean an oily microscope
If a person removes a microscope from the cabinet, properly set up a slide for viewing but can not
focus upon the slide effectively - what could be the problem?
Describe the term “Parfocal.”
Aseptic Techniques (Lab book or test book)
Please review why we disinfect our work areas prior to use.
What method is used to sterilize transfer loops
Why is the culture tube heat sanitized about its rim between removal and replacement of the culture tube
cap
How can microbial levels be controlled on the skin? On surfaces in the environment - like the
telephone? In the air?
Smear Preparation
When making a simple smear of bacteria how much of a volume should we use on the glass slide?
Describe the steps of a simple smear for a bacteria culture from solid TSA and then from both media TSB
Why is heat ‘fixing’ of microbes such an important process
Gram Staining
Be able to fully out line the steps preformed during a gram stain process.
Why do some bacteria gram stain positive while others gram stain negative?
(Explain the physical structure of the two type of bacteria)
Endospore Stain
Microbes of the genera Clostridia and Bacillus form spores as the nutrients on which they
grow diminishes over time.
1 - What are endospores? 2 - Why is hard to kill a endospore?
4 - Name the stain we use to identify endospores
3 - How much water does a endospore
contain?
5 -What survival features does a
endospore offer a prokaryote
compared to a non-sporing microbe?
Acid Fast Staining
When is acid fast staining used?
Questions from lab manual 10th ed
Of the two stains procedures we used in class (gram, and endospore) which one
would you most likely use first to identify an unknown bacterium? And why?
Comparing the staining used with Gram stain technique to that of counter stain, how
does the counter stain differ from the primary stain?
Which is the most critical step in the Gram stain procedure? Why? If this step is left
out how are the final results impacted?
Why must smear thickness be considered before performing a Gram stain?
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