MICROBIOLOGY AND IMMUNOLOGY
EXAM SCRIPT UPDATED COMPLETE
QUESTIONS AND ANSWERS EXPERT
REVIEWED
●● Richest Site of Resident Microbiota
Answer: The colon (large intestine). [cite: 17]
●● Microbial Antagonism
Answer: The hostile chemical or physiological environment created by
resident microbiota that prevents incoming microbes from displacing
them. [cite: 11, 12]
●● Factors Increasing Susceptibility to Infection
Answer: Old age, extreme youth (infancy), genetic or acquired immunity
defects (AIDS), surgery, organ transplants, underlying disease (cancer,
diabetes), chemotherapy, stress, and pregnancy. [cite: 14]
●● Pathogenicity
Answer: A microbe's ability to cause disease. [cite: 20]
●● Virulence
Answer: The relative degree of disease an organism can inflict. [cite: 21]
,●● Infectious Dose (ID)
Answer: The minimum number of microbial cells required to initiate
infection in the host. [cite: 24]
●● Lethal Dose (LD)
Answer: The minimum number of microbes required to kill the host.
[cite: 25]
●● True Pathogens
Answer: Microbes that cause disease in healthy hosts and tend to be
highly virulent. [cite: 29, 30]
●● Opportunistic Pathogens
Answer: Microbes that cause disease only when the host defenses are
compromised. [cite: 29]
●● Exogenous Infection
Answer: An infection where the microbe originates from a source
outside the body (environment, another person, or animal). [cite: 33]
●● Endogenous Infection
Answer: An infection where the microbe already existed on or in the
body as part of the normal microbiota or a silent infection. [cite: 34]
, ●● Adherence Virulence Factors
Answer: Structures like fimbriae and adhesive capsules used by
pathogens to physically attach to host cells. [cite: 37]
●● Anti-Phagocytic Factors
Answer: Virulence factors like cytolytic toxins (Hemolysins/Leukocidin)
that kill phagocytes, capsules that prevent engulfment, or mechanisms to
survive inside phagocytes. [cite: 41]
●● Three Major Virulence Factors for Tissue Damage
Answer: Exoenzymes, toxins, and the ability to induce injurious host
responses (inflammation). [cite: 42]
●● Horizontal Transmission
Answer: The spread of infectious disease from person to person. [cite:
49]
●● Vertical Transmission
Answer: The spread of infectious disease from parent to offspring. [cite:
50]
●● Sign vs. Symptom
EXAM SCRIPT UPDATED COMPLETE
QUESTIONS AND ANSWERS EXPERT
REVIEWED
●● Richest Site of Resident Microbiota
Answer: The colon (large intestine). [cite: 17]
●● Microbial Antagonism
Answer: The hostile chemical or physiological environment created by
resident microbiota that prevents incoming microbes from displacing
them. [cite: 11, 12]
●● Factors Increasing Susceptibility to Infection
Answer: Old age, extreme youth (infancy), genetic or acquired immunity
defects (AIDS), surgery, organ transplants, underlying disease (cancer,
diabetes), chemotherapy, stress, and pregnancy. [cite: 14]
●● Pathogenicity
Answer: A microbe's ability to cause disease. [cite: 20]
●● Virulence
Answer: The relative degree of disease an organism can inflict. [cite: 21]
,●● Infectious Dose (ID)
Answer: The minimum number of microbial cells required to initiate
infection in the host. [cite: 24]
●● Lethal Dose (LD)
Answer: The minimum number of microbes required to kill the host.
[cite: 25]
●● True Pathogens
Answer: Microbes that cause disease in healthy hosts and tend to be
highly virulent. [cite: 29, 30]
●● Opportunistic Pathogens
Answer: Microbes that cause disease only when the host defenses are
compromised. [cite: 29]
●● Exogenous Infection
Answer: An infection where the microbe originates from a source
outside the body (environment, another person, or animal). [cite: 33]
●● Endogenous Infection
Answer: An infection where the microbe already existed on or in the
body as part of the normal microbiota or a silent infection. [cite: 34]
, ●● Adherence Virulence Factors
Answer: Structures like fimbriae and adhesive capsules used by
pathogens to physically attach to host cells. [cite: 37]
●● Anti-Phagocytic Factors
Answer: Virulence factors like cytolytic toxins (Hemolysins/Leukocidin)
that kill phagocytes, capsules that prevent engulfment, or mechanisms to
survive inside phagocytes. [cite: 41]
●● Three Major Virulence Factors for Tissue Damage
Answer: Exoenzymes, toxins, and the ability to induce injurious host
responses (inflammation). [cite: 42]
●● Horizontal Transmission
Answer: The spread of infectious disease from person to person. [cite:
49]
●● Vertical Transmission
Answer: The spread of infectious disease from parent to offspring. [cite:
50]
●● Sign vs. Symptom
