Question 1

Which of the following best describes the main difference between innate and adaptive immunity?

Accepted Answer

Innate immunity recognizes pathogens by predetermined patterns, while adaptive immunity learns to recognize each pathogen individually.

Question 2

Which of the following is NOT a physical barrier that constitutes the first line of defense in innate immunity?

Accepted Answer

Complement proteins

Question 3

A patient with a genetic mutation in the CCR5 gene is less susceptible to which of the following infections?

Accepted Answer

HIV

Question 4

Which granulocyte is primarily responsible for combating parasitic worm infections?

Accepted Answer

Eosinophil

Question 5

Which of the following cells can mature into macrophages once they enter tissues?

Accepted Answer

Monocytes

Question 6

Which of the following is a correct sequence of events in the inflammatory response?

Accepted Answer

Vasodilation, phagocyte migration, tissue repair

Question 7

Which of the following best describes the role of Toll-like receptors (TLRs) in innate immunity?

Accepted Answer

They recognize pathogen-associated molecular patterns (PAMPs) and activate innate immune responses.

Question 8

A bacterium with a thick capsule is able to evade phagocytosis. Which phase of phagocytosis is most directly affected?

Accepted Answer

Adherence

Question 9

Which of the following is NOT a typical sign or symptom of inflammation?

Accepted Answer

Bradycardia

Question 10

Which of the following is a direct outcome of complement activation?

Accepted Answer

Cytolysis, opsonization, and inflammation

Question 11

Which pathway of complement activation is initiated by antigen-antibody complexes?

Accepted Answer

Classical pathway

Question 12

Which complement protein acts as an opsonin to enhance phagocytosis?

Accepted Answer

C3b

Question 13

A patient is infected with a virus. Which interferons are produced by infected cells to signal neighboring cells to produce antiviral proteins?

Accepted Answer

IFN-α and IFN-β

Question 14

Which of the following best explains why fever can be beneficial during an infection?

Accepted Answer

It inhibits the growth of some pathogens and increases the activity of macrophages.

Question 15

Which of the following antimicrobial substances is produced by leukocytes and directly damages microbial membranes?

Accepted Answer

Defensins

Question 16

A patient with a deficiency in C9 complement protein would have the most difficulty with which outcome of complement activation?

Accepted Answer

Cytolysis

Question 17

Which of the following best describes the role of normal flora in innate immunity?

Accepted Answer

They compete with pathogens for nutrients and attachment sites, preventing colonization.

Question 18

Which of the following is a correct description of the ciliary escalator?

Accepted Answer

It is a process by which cilia in the respiratory tract move mucus and trapped particles upward toward the throat.

Question 19

Which of the following best explains why some bacteria with mycolic acid in their cell walls are resistant to digestion after phagocytosis?

Accepted Answer

Mycolic acid prevents the formation of the phagolysosome, inhibiting digestion.

Question 20

Which of the following best describes the function of C5a in the complement cascade?

Accepted Answer

It acts as a chemotactic factor, attracting phagocytes to the site of infection.

Innate Immunity: The Body’s First Line of Defense

Study Guide - Practice Questions