WGU D311 Microbiology Exam Questions and
Answers (2026) | Comprehensive Review
with Detailed Rationales | A+ Verified
• Which environment would contain microbes that are psychrophilic? -✓✓Glaciers
• What is the role of nematodes in soil? -✓✓They photosynthesize and fix
nitrogen.
• Which eukaryote is responsible for producing antibiotics to ward off bacterial
competitors? -✓✓Fungi
• Which symbiotic relationship is an example of mutualism? -✓✓The relationship
between humans and the Escherichia coli colonizing the human gut
• Which type of symbiotic relationship exists between the Escherichia coli (E. coli)
that inhabit the human gut and the humans who utilize the vitamin K produced by
E. coli? -✓✓Mutualism
• Which description of resident microbiota is true? -✓✓Resident microbiota
constantly live on the human body.
• Which relationship is exhibited by intestinal Escherichia coli and their human
host? -✓✓Mutualism
• Which type of disease is transmitted from animals to humans? -✓✓Zoonotic
diseases
,• Which type of disease is acquired in hospital settings? -✓✓Nosocomial diseases
• Which portal of exit can expel the most viral particles? -✓✓Respiratory
• Which type of disease is sickle cell anemia? -✓✓Noninfectious
• Which type of transmission occurs when tuberculosis is spread through small
particles expelled by a cough? -✓✓Droplet transmission
• Which type of transmission occurs when pathogens are spread from mother to
child during breastfeeding? -✓✓Vertical direct contact transmission
• Which type of transmission occurs when an arthropod carries a viral pathogen
inside of its body? -✓✓Biological vector transmission
• Which type of transmission occurs through contact with a fomite? -✓✓Indirect
contact transmission
• Which infected host would be considered a passive carrier? -✓✓A healthcare
professional who does not wash their hands after seeing an infected patient
• How is Giardia lamblia, the causative agent of giardiasis, transmitted? -
✓✓Contaminated food or water
• Which organism is the definitive host of Toxoplasma gondii? -✓✓Birds
, • Which disease is transmitted by animals but not arthropods? -✓✓Rabies
• How can adhesins be described? -✓✓Adhesins found on the surface of pathogens
bind to receptors of host cells.
• Which description indicates a portal of entry? -✓✓Body features through which
pathogens can enter host tissue
• Pathogens produce proteins to prevent the fusion of the phagosome and the
lysosome (phagolysosome).Why does this virulence factor facilitate invasion? -
✓✓It prevents the exposure of pathogens to lethal digestive enzymes.
• Which action refers to a secondary infection? -✓✓An infection by one pathogen
enables another pathogen to cause an infection.
• What differentiates signs from symptoms of disease? -✓✓Signs are measurable;
symptoms are subjective.
• Which procedure does a clinician use to measure a symptom? -✓✓Asking
patients to rate pain on a numerical scale
• During which stage of an infection does a patient feel the worst? -✓✓The period
of illness stage
• What defines the end of the incubation period for an infectious disease? -✓✓The
appearance of nonspecific signs or symptoms of disease
Answers (2026) | Comprehensive Review
with Detailed Rationales | A+ Verified
• Which environment would contain microbes that are psychrophilic? -✓✓Glaciers
• What is the role of nematodes in soil? -✓✓They photosynthesize and fix
nitrogen.
• Which eukaryote is responsible for producing antibiotics to ward off bacterial
competitors? -✓✓Fungi
• Which symbiotic relationship is an example of mutualism? -✓✓The relationship
between humans and the Escherichia coli colonizing the human gut
• Which type of symbiotic relationship exists between the Escherichia coli (E. coli)
that inhabit the human gut and the humans who utilize the vitamin K produced by
E. coli? -✓✓Mutualism
• Which description of resident microbiota is true? -✓✓Resident microbiota
constantly live on the human body.
• Which relationship is exhibited by intestinal Escherichia coli and their human
host? -✓✓Mutualism
• Which type of disease is transmitted from animals to humans? -✓✓Zoonotic
diseases
,• Which type of disease is acquired in hospital settings? -✓✓Nosocomial diseases
• Which portal of exit can expel the most viral particles? -✓✓Respiratory
• Which type of disease is sickle cell anemia? -✓✓Noninfectious
• Which type of transmission occurs when tuberculosis is spread through small
particles expelled by a cough? -✓✓Droplet transmission
• Which type of transmission occurs when pathogens are spread from mother to
child during breastfeeding? -✓✓Vertical direct contact transmission
• Which type of transmission occurs when an arthropod carries a viral pathogen
inside of its body? -✓✓Biological vector transmission
• Which type of transmission occurs through contact with a fomite? -✓✓Indirect
contact transmission
• Which infected host would be considered a passive carrier? -✓✓A healthcare
professional who does not wash their hands after seeing an infected patient
• How is Giardia lamblia, the causative agent of giardiasis, transmitted? -
✓✓Contaminated food or water
• Which organism is the definitive host of Toxoplasma gondii? -✓✓Birds
, • Which disease is transmitted by animals but not arthropods? -✓✓Rabies
• How can adhesins be described? -✓✓Adhesins found on the surface of pathogens
bind to receptors of host cells.
• Which description indicates a portal of entry? -✓✓Body features through which
pathogens can enter host tissue
• Pathogens produce proteins to prevent the fusion of the phagosome and the
lysosome (phagolysosome).Why does this virulence factor facilitate invasion? -
✓✓It prevents the exposure of pathogens to lethal digestive enzymes.
• Which action refers to a secondary infection? -✓✓An infection by one pathogen
enables another pathogen to cause an infection.
• What differentiates signs from symptoms of disease? -✓✓Signs are measurable;
symptoms are subjective.
• Which procedure does a clinician use to measure a symptom? -✓✓Asking
patients to rate pain on a numerical scale
• During which stage of an infection does a patient feel the worst? -✓✓The period
of illness stage
• What defines the end of the incubation period for an infectious disease? -✓✓The
appearance of nonspecific signs or symptoms of disease
