UPDATED TEST BANK EXAM 2024-2025|58
QUESTIONS WITH CORRECT ANSWERS
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The ability of some microbes, such as Trypanosoma or Giardia to alter their surface molecules and evade
destruction by the host's antibodies is called
A) antigenic variation.
B) lysogenic conversion.
C) virulence.
D) cytopathic effect.
E) cytocidal effect - ANSWERS -antigenic variation
Most pathogens that gain access through the skin
A) can penetrate intact skin.
B) just infect the skin itself.
C) enter through hair follicles and sweat ducts.
D) must adhere first while their invasive factors allow them to penetrate.
E) must be injected - ANSWERS -enter through hair follicles and sweat ducts
- ANSWERS -mucous membranes of the respiratory tract
The ID50 is
A) a measure of pathogenicity.
B) the dose that will cause an infection in 50 percent of the test population.
C) the dose that will kill some of the test population.
, D) the dose that will cause an infection in some of the test population.
E) the dose that will kill 50 percent of the test population - ANSWERS -the dose that will cause an
infection in 50 percent of the test population
All of the following contribute to a pathogen's invasiveness EXCEPT
A) toxins.
B) capsules.
C) cell wall components.
D) hyaluronidase.
E) coagulases - ANSWERS -toxins
Which of the following statements is FALSE?
A) Leukocidins destroy neutrophils.
B) Hemolysins lyse red blood cells.
C) Hyaluronidase breaks down substances between cells.
D) Kinase destroys fibrin clots.
E) Coagulase destroys blood clots - ANSWERS -Coagulase destroys blood clots
- ANSWERS -they are resistant to heat
Endotoxins are
A) associated with gram-positive bacteria.
B) molecules that bind nerve cells.
C) part of the gram-negative cell wall.
D) excreted from the cell.
E) A-B toxins - ANSWERS -part of the gram-negative cell wall
Which of the following is NOT a membrane-disrupting toxin?
A) A-B toxin