WGU D311 OA Final Exam/ WGU D311 Microbiology Objective Assessment
Final Exam
WGU D311 OA FINAL EXAM/ WGU D311 MICROBIOLOGY
OBJECTIVE ASSESSMENT FINAL EXAM NEWEST 2025/2026
ACTUAL EXAM COMPLETE 260 QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED
A+||BRAND NEW VERSION!!
Which method of microscopy uses a laser to scan multiple planes and produces a
three-dimensional image that can be used to visualize the internal structure of a
biofilm?
a) Transmission electron microscopy
b) Brightfield microscopy
c) Scanning electron microscopy
d) Confocal microscopy
D
This type of microscopy is used to visualize clear images of biofilms by focusing on
one z-plane at a time
Which technique uses a single dye to emphasize particular structures in the
specimen?
a) Differential staining
b) Acid-fast staining
c) Gram staining
d) Simple staining
D
Which bacterial structure determines the different outcomes of the Gram stain?
a) Endospore
b) Peptidoglycan
1|Page
, WGU D311 OA Final Exam/ WGU D311 Microbiology Objective Assessment
Final Exam
c) Capsule
d) Mycolic acid
B
Bacteria are classified as gram negative or gram positive based on how many
layers of peptidoglycan are in their cell walls
A hemagglutination assay is applied to dilutions of a sputum sample from a
person with signs of an upper respiratory infection. When the scientists evaluated
the sputum samples, they did not observe hemagglutination. Which microbial
cause of upper respiratory infections has been ruled out?
a) Taenia saginata
b) Rickettsia rickettsii
c) Toxoplasma gondii
d) Influenza virus
D
Influenza virus uses the adhesin hemagglutinin to spread infection. If the results
are negative, then we know that this URI isn't influenza
The antibiotic doxycycline works by inhibiting protein synthesis through binding to
the 30S ribosomal subunit. Why would this antibiotic be ineffective against
viruses?
a) Viruses are eukaryotic cells, not prokaryotic cells.
b) Viruses do not have ribosomes.
c) Viruses only have smooth endoplasmic reticula.
d) Viruses have 40S ribosomal subunits.
B
Viruses are acellular and only consist of DNA or RNA
2|Page
, WGU D311 OA Final Exam/ WGU D311 Microbiology Objective Assessment
Final Exam
A patient who is immunosuppressed develops skin pustules and itching. What is a
plausible cause of these symptoms?
a) An opportunistic endoparasitic infection
b) An opportunistic bacterial infection
c) An avirulent protozoal infection
d) A highly virulent allergic skin disease
B
This is the most correct because the patient's signs are consistent with a bacterial
skin infection. Opportunistic pathogens can only cause disease in situations where
a patient's immune defenses are down which is the case for this question.
A culture of fluid collected from a healthy person via a bronchoalveolar lavage
yielded growth of Staphylococcus aureus; however, a culture of a similarly
collected sample from a person sneezing and coughing also yielded growth of
Staphylococcus aureus. How can the same bacteria cause infection and symptoms
in one person but not in another person?
a) Commensal bacteria became opportunistic.
b) Nonpathogenic bacteria became avirulent.
c) Both people must be immunocompromised.
d) One of the samples yielded a false negative result.
A
Commensal bacteria can become pathogenic when their growth rate outnumbers
the amount of other bacteria
Why can both cats and people be infected with herpes virus but not infect each
other?
a) Infectivity must be low for these viruses.
b) Innate immunity differs between species.
c) These viruses are species-specific.
d) Virus particles are short-lived.
3|Page
, WGU D311 OA Final Exam/ WGU D311 Microbiology Objective Assessment
Final Exam
C
Feline herpes virus is specific to cats. Most mammals have their own type of
herpes virus that cannot be transmitted to other species
Fimbria is a virulence factor of Escherichia coli necessary for an infection to
develop. Which treatment may be helpful to prevent urinary tract infections
caused by Escherichia coli on the basis of the bacteria's virulence factor?
a) Probiotic because it interferes with capsule formation by Escherichia coli
b) Antitoxin because it counters endotoxin released by viable Escherichia coli
c) Cranberry extract because it interferes with the adherence of Escherichia coli to
the bladder wall
d) Antiparasitic because it prevents antigenic drift common to Escherichia coli
C
Cranberry extract has the ability to inhibit Escherichia coli adhesion
Which statement describes prokaryotic cells?
a) Prokaryotic cells are found in coccus form in both pairs and clusters.
b) Prokaryotic cells have multiple rod-shaped chromosomes.
c) Prokaryotic cells are found in chains of rods but not single rods.
d) Prokaryotic cells have a nucleus surrounded by a complex nuclear membrane.
A
This is correct because prokaryotic cells can form cocus in both pairs and clusters
Which statement describes eukaryotic cells?
a) The exoskeletons of eukaryotic cells maintain and support the cells' shapes.
b) The nuclei of eukaryotic cells are surrounded by complex nuclear membranes.
c) The genomes of eukaryotic cells are usually packaged in single circular
chromosomes.
4|Page
Final Exam
WGU D311 OA FINAL EXAM/ WGU D311 MICROBIOLOGY
OBJECTIVE ASSESSMENT FINAL EXAM NEWEST 2025/2026
ACTUAL EXAM COMPLETE 260 QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED
A+||BRAND NEW VERSION!!
Which method of microscopy uses a laser to scan multiple planes and produces a
three-dimensional image that can be used to visualize the internal structure of a
biofilm?
a) Transmission electron microscopy
b) Brightfield microscopy
c) Scanning electron microscopy
d) Confocal microscopy
D
This type of microscopy is used to visualize clear images of biofilms by focusing on
one z-plane at a time
Which technique uses a single dye to emphasize particular structures in the
specimen?
a) Differential staining
b) Acid-fast staining
c) Gram staining
d) Simple staining
D
Which bacterial structure determines the different outcomes of the Gram stain?
a) Endospore
b) Peptidoglycan
1|Page
, WGU D311 OA Final Exam/ WGU D311 Microbiology Objective Assessment
Final Exam
c) Capsule
d) Mycolic acid
B
Bacteria are classified as gram negative or gram positive based on how many
layers of peptidoglycan are in their cell walls
A hemagglutination assay is applied to dilutions of a sputum sample from a
person with signs of an upper respiratory infection. When the scientists evaluated
the sputum samples, they did not observe hemagglutination. Which microbial
cause of upper respiratory infections has been ruled out?
a) Taenia saginata
b) Rickettsia rickettsii
c) Toxoplasma gondii
d) Influenza virus
D
Influenza virus uses the adhesin hemagglutinin to spread infection. If the results
are negative, then we know that this URI isn't influenza
The antibiotic doxycycline works by inhibiting protein synthesis through binding to
the 30S ribosomal subunit. Why would this antibiotic be ineffective against
viruses?
a) Viruses are eukaryotic cells, not prokaryotic cells.
b) Viruses do not have ribosomes.
c) Viruses only have smooth endoplasmic reticula.
d) Viruses have 40S ribosomal subunits.
B
Viruses are acellular and only consist of DNA or RNA
2|Page
, WGU D311 OA Final Exam/ WGU D311 Microbiology Objective Assessment
Final Exam
A patient who is immunosuppressed develops skin pustules and itching. What is a
plausible cause of these symptoms?
a) An opportunistic endoparasitic infection
b) An opportunistic bacterial infection
c) An avirulent protozoal infection
d) A highly virulent allergic skin disease
B
This is the most correct because the patient's signs are consistent with a bacterial
skin infection. Opportunistic pathogens can only cause disease in situations where
a patient's immune defenses are down which is the case for this question.
A culture of fluid collected from a healthy person via a bronchoalveolar lavage
yielded growth of Staphylococcus aureus; however, a culture of a similarly
collected sample from a person sneezing and coughing also yielded growth of
Staphylococcus aureus. How can the same bacteria cause infection and symptoms
in one person but not in another person?
a) Commensal bacteria became opportunistic.
b) Nonpathogenic bacteria became avirulent.
c) Both people must be immunocompromised.
d) One of the samples yielded a false negative result.
A
Commensal bacteria can become pathogenic when their growth rate outnumbers
the amount of other bacteria
Why can both cats and people be infected with herpes virus but not infect each
other?
a) Infectivity must be low for these viruses.
b) Innate immunity differs between species.
c) These viruses are species-specific.
d) Virus particles are short-lived.
3|Page
, WGU D311 OA Final Exam/ WGU D311 Microbiology Objective Assessment
Final Exam
C
Feline herpes virus is specific to cats. Most mammals have their own type of
herpes virus that cannot be transmitted to other species
Fimbria is a virulence factor of Escherichia coli necessary for an infection to
develop. Which treatment may be helpful to prevent urinary tract infections
caused by Escherichia coli on the basis of the bacteria's virulence factor?
a) Probiotic because it interferes with capsule formation by Escherichia coli
b) Antitoxin because it counters endotoxin released by viable Escherichia coli
c) Cranberry extract because it interferes with the adherence of Escherichia coli to
the bladder wall
d) Antiparasitic because it prevents antigenic drift common to Escherichia coli
C
Cranberry extract has the ability to inhibit Escherichia coli adhesion
Which statement describes prokaryotic cells?
a) Prokaryotic cells are found in coccus form in both pairs and clusters.
b) Prokaryotic cells have multiple rod-shaped chromosomes.
c) Prokaryotic cells are found in chains of rods but not single rods.
d) Prokaryotic cells have a nucleus surrounded by a complex nuclear membrane.
A
This is correct because prokaryotic cells can form cocus in both pairs and clusters
Which statement describes eukaryotic cells?
a) The exoskeletons of eukaryotic cells maintain and support the cells' shapes.
b) The nuclei of eukaryotic cells are surrounded by complex nuclear membranes.
c) The genomes of eukaryotic cells are usually packaged in single circular
chromosomes.
4|Page
