Answer Options:
True
False
Answer: True
Question: Following are data collected from a serial dilution experiment using E. coli in which you plated 100 microliters (0.1 mL) onto each of the following plates. What is the concentration of cells in the original stock solution? Tube Dilution: 10^-4, 10^-5, 10^-6, 10^-7 Plate Colonies: TMTC, 968, 156, 14
Answer Options:
1.56 x 10^8 CFU/mL
1.56 x 10^9 CFU/mL
1.56 x 10^7 CFU/mL
Answer: 1.56 x 10^8 CFU/mL
Question: Use the following image to answer question 23. What type of organism is infected by the viruses shown below?
Answer Options:
Fungus
Bacteria
Archaea
Humans
Answer: Bacteria
Question: If you perform a Gram stain on a pure culture of bacteria and you observe purple, round-shaped cells at 400X magnification. How would you characterize this particular bacteria?
Answer Options:
Gram negative rods
Gram positive rods
Gram negative cocci
Gram positive cocci
Answer: Gram positive cocci
Question: Calculate the total magnification if you are using a microscope with an ocular magnification of 5x and an objective magnification of 200x.
Answer Options:
250x
5x
200x
1000x
Answer: 1000x
Question: The potassium hydroxide (KOH) or string test distinguishes between Gram-positive and Gram-negative bacteria and used to validate Gram Stain results.
Answer Options:
True
False
Answer: True
Question: Using that same microscope and those same lenses (10x oculars and 25x objective), you also note that the NA of the objective lens is 1.1. What is the resolving power of the microscope when you’re looking at a sample using a 500 nm wavelength of light?
Answer Options:
454.5 nm
2.0 mm
227.3 nm
350 nm
Answer: 227.3 nm
Question: Pelagibacter ubique is an organism that thrives in low-nutrient environments. The correct term used to describe an organism like this is:
Answer Options:
Copiotroph
Oligotroph
Photoautotroph
Chemoheterotroph
Answer: Oligotroph
Question: Sensitive E. coli cells grow on TSA plus streptomycin media.
Answer Options:
True
False
Answer: False
Question: True or False: Plants likely generated the oxygen portion of the earth’s atmosphere.
Answer Options:
True
False
Answer: True
Question: Normal microbiota provide protection from infection in each of the following ways EXCEPT:
Answer Options:
they produce antibacterial chemicals.
they compete with pathogens for nutrients.
they make the chemical environment unsuitable for nonresident bacteria.
they produce lysozyme.
Answer: they produce lysozyme.
Question: Which cellular structure is fundamentally different between Gram positive and negative bacteria and impacts the differential staining during the Gram Stain procedure?
Answer Options:
Peptidoglycan
Outer Membrane
Chitin
Cytoplasm
Answer: Outer Membrane
Question: True or False: Most animal vectors are arthropods.
Answer Options:
True
False
Answer: True