Study sets, textbooks, questions
Upgrade to remove ads
Microbiology Lab Final Exam Review Guide
Terms in this set (66)
Microbes are ___________, and most are not ______________.
Multiple species can grow as _____________ on nutrient media when a plate is exposed to many types of environments.
the number of ____________ colonies on a plate is essentially the number of cultivable species from the environment you test.
What is the measure of microbial diversity?
the number of unique colonies (total number doesn't matter)
-unique colonies directly correlates to microbial diversity
All living things require __________ to survive, grow and reproduce.
What are the 6 necessary nutrient components?
Complex vs. defined vs. selective vs. differential media
What are the types of various media that we used in lab? How are they classified? Were any a combination of these types?
All media in the lab must be ___________ prior to the use of experiments.
How do we sterilize in the lab?
-Autoclave (121 degrees C and 15 pounds psi for >15 min) (if the pressure goes up so does the temperature)
-Vacuum filtration (used for water quality) is also commonly known to sterilize special media components that are heat sensitive (ex: protein additives like growth factors)
What is required in the laboratory in order to specifically study a particular bacterial species of interest, and to reduce contamination of the cultures, yourself, and the area in which you are working?
aseptic technique (minimizes contamination, but does not sterilize it)
Aseptic vs. sterile technique
Why can't you have sterile techniques in the laboratory?
Aseptic technique in broths vs. slants vs. plates (differences and advantages/disadvantages)
How can a successful inoculation be checked visually?
A broth culture will become ______ whereas successful growth on slants or plates would be the appearance of ____________.
Define a colony
Difference between a colony and a cell
What is the importance of isolating and selecting a single colony in which to perform your experiments?
What are the various plate-streaking techniques you've used?
If done correctly, quadrant streaking tends to provide _____________. Why is this important?
The _____________ is an invaluable tool to the microbiologist.
What does the microscope allow you to do?
visualize individual cells and their components
Anatomy, function and magnifying ability of our compound light microscope
Know the resolving power of our microscopes
The ________________ of our microscopes is a function of the numerical aperture of the ocular and objective lenses and the light's wavelength.
As the _______________ power (magnification) increases, the stage distance to objective and the field of view decreases and the resolving power increases.
Why does the oil immersion work for clarity and color contrast?
How you use oil immersion lens on the microscope
-Similar to how glass bends light
-Doesn't allow scattered light to be lost
What was the procedure for making bacterial smears on slides? Why is the heat fixing step so important?
-Critical to imobilize cells so they won't slide off with water
-Makes a thin (single) layer of cells on slide (so more light will pass through)
Most cells are what color?
Why is simple staining used?
To better resolve bacterial cells and their contents, providing bold contrast against the background so that features such as cell morphology, size, and arrangement can be discerned.
How does a stain work to bind a bacterial cell?
We mainly used simple staining with ______________, providing a positive stain of the cell
What is simple negative staining and why is it useful?
Simple positive vs. negative staining?
Positive = imaging object you want to see (staining the cell)
-mythl blue (binds bacterial cell wall, forms electric static wall)
Negative = staining the background (gives really accurate dimensions)
-nigrasin (don't heat fix because it will shrink cell)
Who developed the gram staining procedure in the late 19th century?
Hans Christian Gram
How an unknown bacteria stains in this test, gram positive or gram negative.
Cell __________ structure and ____________ inherently provides the ability to differentiate between bacterial cells and species
What is the most important and error prone step in a differential stain?
Be able to describe the staining process and why (on a molecular level, cells stain either positively or negatively)
What are the two types of differential staining?
Gram differential staining
-Positive or negative
-Most critical step: decolorizer (alcohol, gets ride of outer membrane)
Spore differential staining
Decolorizing stain problem
-if too long, takes away crystal violet (and leads to a false negative)
-if not long enough, false positive (less common)
What are the two most important bacteria that produce endospores?
-bacillus (soil bacteria)
-clostridium (more common)
Know the anatomy of an endospore
What conditions stimulate their production and their appearance under the microscope in gram and spore staining? Why are these important medically and what role do they serve to assess sterilization practices?
List the major environmental parameters that can be changed in order to promote and/or limit bacterial growth?
What are the temperature range classifications for bacteria?
On a molecular level, what happens to bacteria if they are forced to live outside "comfortable" ranges of temperature?
-Too high = kills
-Too low: slows down growth
We used ________ and __________ as antimicrobial agents and assessed affects on growth using the Kirby-Bauer method.
How do perform this assay (Kirby-Bauer method)?
natural vs. adaptive resistance
-Adaptive: develops over time (lots of mechanisms to do this)
Why would gram positives be more susceptible to antibiotics that target the peptidogylcan cell wall?
What general classes of antibiotics might be specifically effective against gram negatives?
Gram positive and Gram negative wth Lysozymes and antibiotics
-Gram positive: lysozymes are most effective (dip disk into plate)
-Gram negative: antibiotics (gram negative is less sensitive to antibiotics)
4 classes we tested (measured the diameter of the zone of inhibition)
-Measuring at what antibiotic concentration can this cell grow
-Just because you get zone does not mean cell is sensitive to antibiotic
Water distribution lines that are used for human consumption and use must be routinely ________ by water boards for the presence of ________ bacteria.
-Typically the subset of species that are tested for (easy to culture and identify) (not typically found in water or soil)
-Can be found in water for a relatively long period of time (endemic to the mammalian gut)
-Their identification is an indicator of sewage contamination of a water source
We use the ____________ method for water quality testing.
Membrane filter method
How does the membrane filter method work and how is it different from the classical most probable number (MPN) determination method?
How is MPN determined with the MF method? What does it mean and how do we use it?
_________________ is a common procedure for microbiologists.
What are some of the techniques, tools, and reagents we use to be able to differentiate between Streptococcus/Enterococcus species?
Compare and contrast how we approach unknown identification for this chapter versus the environmental sampling unknown in the first half of the semester, were these presumptive or confirmatory identifications or somewhere in the middle?
Sets with similar terms
Micro 107 Quiz 1
Ch. 4: Microscopy and Staining
micro lab test 2
Microbiology Lab Final Review
Other sets by this creator
Microbiology Lab Study Guide
Microbiology Lab (BIOL 225): Final Exam
Microbiology Exam 4 Study Guide