Questions and Answers
What biosafety level are most microbes in our lab?
According to Dr. Franklund, what is the most dangerous thing in our microbiology lab?
What type of fire extinguisher does our lab have?
Where is our lab's tornado evacuation location?
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What should you put down the sink in our lab?
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What term refers to the edge of a colony?
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What term refers to a macroscopic pile of microscopic cells?
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Umbronate is an example of a colony's ___________.
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The most common color of bacterial colonies is what?
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What solidifying agent is added to our plated media?
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What is the maximum magnification using our microscopes?
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What term refers to the ability to distinguish two objects as being separate from each other?
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Which of our objective lenses has the most working distance?
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How big is one ocular micrometer tick when using our 100X objective lens?
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What is the purpose of immersion oil?
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How large are most bacteria?
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What term refers to ball-shaped microbes found in chains?
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What term refers to spiral-shaped bacteria with axial filaments?
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What term refers to rod-shaped bacteria?
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What term refers to ball-shaped bacteria that appear in packets of eight cells?
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What is the primary stain of the Gram stain?
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What color is a properly stained Gram negative bacterium?
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Who invented the Gram stain?
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What would happen if you apply the destain for too long in the Gram stain?
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What is the function of iodine in the Gram stain?
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What is the main function of a microbial capsule?
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What are most microbial capsules made of?
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What did we stain the background with in our capsule stains?
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What type of microbe is Cryptococcus neoformans?
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How did capsules appear in our capsule stain?
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What is the purpose of a bacterial endospore?
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What was the primary stain in the endospore stain?
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What was the mordant in the endospore stain?
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Which pair microbes make endospores?
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What color did endospore stain in our lab?
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Why do we call this the acid fast stain?
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Which acid fast staining technique did we use?
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Which two diseases are typically caused by acid fast bacteria?
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What color did our acid fast bacteria appear?
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What was the secondary stain in the acid fast procedure?
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What structure do most bacteria use for motility in liquid media?
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What term refers to microbes with a single flagellum at one end?
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What term refers to bacteria with tufts of flagella at their end?
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What term refers to bacteria with flagella at both of their ends?
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What term refers to bacteria that have flagella all around their cell margin?
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If you put 2 ml of sample into 8 ml of diluent, what is the tube dilution factor?
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If you have three tubes with 1 ml of diluent in each and you sequentially transfer 1 ml of sample to each (i.e., 1 ml to #1, then 1 ml from #1 to #2 and 1 ml from #2 to #3), what is the SDF for tube 3?
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If you dilute a sample 1000X, plate 0.1 ml, and observe 150 colonies the next day, how many cfu/ml were in the original culture?
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If you have a culture with 50,000,000 cfu/ml and you serially dilute it by transferring 1 ml into 9 ml of diluent five times, how many colonies would you expect if you plate 0.2 ml?
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Assume that you have a culture with 4,000,000 cfu/ml and you plated 0.5 ml. The next day you observe 200 colonies. How much was this culture diluted prior to plating?
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What kind of microbes are bacteriophage?
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What term refers to the protein coat that surrounds the phage genome?
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What are these holes referred to as?
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Assume that you dilute a phage stock by adding 0.1 ml to 0.9 ml in 7 tubes sequentially and then plate 0.1 ml on host cells. If you saw 100 holes on the plate the next day, how many pfu/ml were in your stock?
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In our lab, how many drops do we assume that it takes to make 1 ml?
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What are the clear areas around this disk called?
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What is the target of tetracycline's action?
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What group of compounds includes aldehydes?
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When you use isopropanol on your skin, it is acting as __________.
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Which of the following compounds is a surfactant?
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Identify this protozoan pathogen.
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Identify this protozoan pathogen.
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Identify this protozoan pathogen.
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Identify this protozoan pathogen.
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Identify this protozoan pathogen.
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What biomolecule are fungal cell walls composed of?
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Which fungus does this image represent?
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Which fungus does this image represent?
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Which fungus does this represent?
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Which fungus does this image represent?
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What type of microbe grows best between 20 and 40°C?
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What type of microbe grows best between pH 3 and pH 4?
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What type of microbe will only grow in the presence of 5 to 15% NaCl?
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What pH would a neutrophile grow best at?
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Which of these best describes most bacterial pathogens?
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What is the oxygen indicator found in Brewer's anaerobic agar?
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In a GasPak jar, what is oxygen converted into?
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What type of growth is exhibited in this fluid thioglycollate tube?
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What type of growth is exhibited in this fluid thioglycollate tube?
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What type of microbe would grow inside a GasPak jar but not outside of it?
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What percent of a microbial population will remain after one D-value has transpired?
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If we hold the time of exposure constant at 10 minutes and it required 80°C to achieve sterilization, 80°C is the ___________.
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If we hold the temperature constant at 70°C and it requires 23 minutes to achieve sterilization, 23 minutes is the ______.
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Why is Bacillus cereus so resistant to killing by heat?
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What term refers to the complete killing of all microbes on a surface?
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Which of these microbes is most resistant to UV killing?
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Which of these has the shortest wavelength?
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Which of these is the most germicidal wavelength of UV light?
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What sort of cellular damage is caused by UV light?
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What type of UV light is used in tanning booths (hopefully)?
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What biochemical test are all coliforms positive for?
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What color is a positive urease test?
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What reaction would a TSI tube show if glucose was fermented, but not sucrose or lactose?
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Which amino acid is broken down in a positive indole test?
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What color does a positive citrate test turn?
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What compound is broken down in a catalase test?
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What inhibitory molecule is found in EF broth?
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What type of hemolysis results in complete clearing on blood agar?
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What antibiotic is found on our A disks?
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What type of media is mannitol salt agar?
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Study Notes
Biosafety and Lab Safety
- Most microbes in the lab are classified as BSL-1.
- The most dangerous item in the microbiology lab is the Bunsen burner.
- The lab has an ABC type fire extinguisher.
- Tornado evacuation location is designated as the hallway.
- Only water should be disposed of down the sink in the lab.
Colony Characteristics and Microscopy
- The edge of a colony is referred to as the margin.
- A macroscopic pile of microscopic cells is called a colony.
- Umbronate describes a colony's elevation.
- The most common color for bacterial colonies is tan.
- Agarose serves as the solidifying agent in plated media.
- The maximum magnification using lab microscopes is 1000X.
- Resolution refers to the ability to distinguish two separate objects.
Bacterial Morphology
- Rod-shaped bacteria are termed bacilli.
- Ball-shaped bacteria in chains are called streptococci.
- Spiral-shaped bacteria with axial filaments are spirochetes.
- Ball-shaped bacteria that appear in packets of eight cells are termed sarcina.
Gram Staining Procedure
- The primary stain in the Gram stain process is crystal violet.
- Gram-negative bacteria appear pink after proper staining.
- The Gram stain was invented by Hans Christian Gram.
- If the destain process is prolonged, both Gram-positive and negative cells appear pink.
- Iodine functions as a mordant in the Gram staining process.
Microbial Structures and Functions
- The primary function of a microbial capsule is to evade phagocytes.
- Capsules are typically made of polysaccharides.
- Bacterial endospores are primarily used for survival.
- Endospores appear green when stained with malachite green.
Acid-Fast Staining
- The acid-fast stain is so named because the primary stain does not wash out in acid.
- Kinyoun staining technique is used for acid-fast bacteria.
- Common diseases caused by acid-fast bacteria include tuberculosis and leprosy.
- Acid-fast bacteria appear dark red after staining, with methylene blue as the secondary stain.
Microbial Mobility
- Most bacteria utilize flagella for motility in liquid media.
- Bacteria with a single flagellum at one end are called monotrichous.
- Bacteria with flags at both ends are referred to as amphitrichous, while those with tufts are lophotrichous.
Dilution and Colony Counting
- To calculate tube dilution factor: when 2 ml is put into 8 ml of diluent, the factor is 5X.
- A culture diluted 1000X and yielding 150 colonies results in an original concentration of 1,500,000 cfu/ml.
- Serial dilutions can be calculated based on the amount transferred and plated.
Bacteriophage and Viral Structure
- Bacteriophages are classified as acellular microbes.
- The protein coat surrounding the phage genome is termed capsid.
- Clear areas around disks on agar plates are known as zones of inhibition.
Microbial Resistance and Sterilization
- Sterilization refers to complete killing of all microbes on a surface.
- Bacillus cereus is known for its resistance to heat due to endospore formation.
- Germicidal effectiveness of UV light is highest at a wavelength of 260 nm, producing T-T dimers in DNA.
Biochemical Testing
- All coliforms test positive for lactose fermentation, indicative of their metabolic capability.
- A positive urease test results in a pink coloration.
- TSI (Triple Sugar Iron) test shows K/A if only glucose is fermented.
- Indole test detects the breakdown of tryptophan, producing a positive result when the indicator changes color.
- The hemolytic pattern of complete clearing on blood agar is classified as beta hemolysis.
Growth Conditions for Microbes
- Mesophiles thrive best at temperatures between 20 and 40°C.
- Acidophiles prefer environments with a pH of 3 to 4.
- Halophiles grow optimally in high salt concentrations, between 5% to 15% NaCl.
- Neutrophiles grow best at a pH of 7, typical of many pathogens.
Media and Inhibition
- Mannitol salt agar is both selective and differential for specific microorganisms.
- Antibiotic sensitivity testing, such as with Bacitracin on A disks, identifies susceptibility or resistance of bacteria.
Antiseptics and Disinfectants
- Isopropanol acts as an antiseptic when used on skin.
- Roccal is identified as a surfactant compound effective in microbe control.
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Description
Test your knowledge on microbiology lab safety protocols and equipment with this quiz. Questions cover biosafety levels, hazards, and fire safety measures specific to the lab environment. Perfect for students and professionals looking to enhance their safety awareness in microbiology labs.