Question 1

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

Accepted Answer

TLRs attach to pathogen-associated molecular patterns (PAMPs) and induce cytokine release.

Question 2

A patient presents with a high white blood cell (WBC) count. Which of the following is the LEAST likely cause?

Accepted Answer

Viral infection

Question 3

Which physical factor is most directly responsible for transporting microbes away from the lungs?

Accepted Answer

Ciliary escalator

Question 4

Which chemical factor found in tears is responsible for destroying bacterial cell walls?

Accepted Answer

Lysozyme

Question 5

A patient with a genetic deficiency in complement proteins is MOST likely to experience which of the following?

Accepted Answer

Increased susceptibility to infections

Question 6

Which of the following is a correct sequence of events in phagocytosis?

Accepted Answer

Chemotaxis → Adherence → Ingestion → Digestion

Question 7

Which of the following is NOT a function of the complement system?

Accepted Answer

Antibody production

Question 8

Which pathway of complement activation is triggered by antibodies binding to antigens?

Accepted Answer

Classical pathway

Question 9

A bacterial capsule helps the pathogen evade the immune system by:

Accepted Answer

Preventing complement activation

Question 10

Which of the following best explains why normal microbiota are considered part of innate immunity?

Accepted Answer

They compete with pathogens for space and nutrients, and may produce substances harmful to pathogens.

Question 11

Which of the following is a granulocyte that is primarily involved in allergic responses?

Accepted Answer

Basophil

Question 12

During inflammation, which molecule is responsible for increased permeability of blood vessels?

Accepted Answer

Histamine

Question 13

Which of the following best describes the function of interferon-alpha ($$\mathrm{IFN}-\alpha) $$and interferon-beta ($$\mathrm{IFN}-\beta$$)?

Accepted Answer

They cause neighboring cells to produce antiviral proteins that inhibit viral replication.

Question 14

Which of the following iron-binding proteins is found in milk, saliva, and mucus?

Accepted Answer

Lactoferrin

Question 15

A patient with a fever has a body temperature above 37°C. What is the immediate cause of the hypothalamus resetting to a higher temperature?

Accepted Answer

Prostaglandins released in response to cytokines

Question 16

Which of the following is a correct description of opsonization?

Accepted Answer

Coating of a microorganism with serum proteins to enhance phagocytosis

Question 17

Which of the following is a multi-step process that involves chemotaxis, adherence, ingestion, and digestion?

Accepted Answer

Phagocytosis

Question 18

Which of the following is a broad-spectrum antimicrobial peptide that inhibits cell wall synthesis and forms pores in microbial membranes?

Accepted Answer

Defensin

Question 19

Which of the following best explains why the very young and elderly are more susceptible to infectious diseases?

Accepted Answer

Their innate immune responses are less effective.

Question 20

Which of the following is the main function of the membrane attack complex (MAC) formed during complement activation?

Accepted Answer

Cytolysis of target cells

Innate Immunity: Nonspecific Defenses of the Host – Study Notes

Study Guide - Practice Questions