Question: The “run” movement of bacterial flagella is characterized by which of the following?

Answer Options:
Clockwise rotation of the flagellum
A sudden stop and change in direction
Counterclockwise rotation of the flagellum
Movement away from a positive chemical stimulus

Answer: Counterclockwise rotation of the flagellum

Question: Use the image of the mutations in the SARS-CoV-2 genome to answer the question below: The first strain of the virus sequenced was the Washington strain in the United States. Based on what you know about mutations, which strain likely arose second?

Answer Options:
Utah
Colorado
Kansas
California

Answer: Utah

Question: ________ microscopy involves the use of dyes that must be exposed to UV light.

Answer Options:
Electron
Bright field
Phase-contrast
Fluorescent
Dark field

Answer: Fluorescent

Question: The purpose of the complement system is to:

Answer Options:
Produce neutrophils and macrophages
Enhance clearing of dead and damaged cells during infection
Produce phagocytes
All of the options are true

Answer: Enhance clearing of dead and damaged cells during infection

Question: The nucleic acid sequence resulting from the replication of the following strand would be: 5′- GTTCAGCCAGTAACGG -3′

Answer Options:
5′- CAAUGCGGUCAUUCCG -3′
3′- CAAGTCGGTCATTGCC -5′
3′- CAAUGCGGUCAUUCCG -5′
5′- CAAGTCGGTCATTGCC -3′

Answer: 5′- CAAGTCGGTCATTGCC -3′

Question: Which bacterial species is found on human skin as part of the normal flora?

Answer Options:
Bacillus subtilis
Escherichia coli
Staphylococcus epidermidis
Enterococcus faecalis

Answer: Staphylococcus epidermidis

Question: You want to determine the cell density of a liquid bacterial culture so you perform a serial dilution. You inoculate three TSA plates with 100 µL aliquots from three consecutive dilution tubes. After incubation, you count the colonies on each plate and obtain the results listed below. Which plates should be chosen to calculate the original cell density (OCD)? Plate A: 337 CFU Plate B: 35 CFU Plate C: 4 CFU

Answer Options:
Plate A
Plate B
Plate C
None of the plates

Answer: Plate B and Plate C

Question: Use this image to answer the question: The structure or area represented by letter C is the:

Answer Options:
Cell wall
Teichoic acid
Lipopolysaccharide
Periplasmic space

Answer: Periplasmic space

Question: An isolation streak is not necessary for obtaining a pure culture. True False

Answer: False

Question: Hormones secreted by the hypothalamus control hormones secreted by the anterior pituitary gland.

Answer Options:
True
False

Answer: True

Question: Calculate the total magnification if you are using a microscope with an ocular magnification of 10x and an objective magnification of 300x.

Answer Options:
310x
30x
3000x
210x

Answer: 3000x