Question 1

Which of the following best describes the role of lysozyme in innate immunity?

Accepted Answer

It destroys the cell wall of bacteria, particularly by hydrolyzing the bonds in peptidoglycan.

Question 2

A patient presents with an increased number of eosinophils in their blood. Which of the following is the most likely cause?

Accepted Answer

A parasitic worm infection or an allergic reaction

Question 3

Which of the following is NOT a function of the normal microbiome in innate immunity?

Accepted Answer

Directly phagocytizing invading bacteria

Question 4

Which of the following best explains why the skin is an effective barrier to pathogens?

Accepted Answer

It contains multiple layers of tightly packed cells and is reinforced by collagen fibers.

Question 5

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

Accepted Answer

Chemotaxis → Adhesion → Ingestion → Maturation → Killing → Elimination

Question 6

Which of the following statements about complement activation is TRUE?

Accepted Answer

All complement activation pathways converge at the activation of C3.

Question 7

A patient with a genetic defect in Toll-like receptors (TLRs) would most likely have which of the following problems?

Accepted Answer

Impaired ability to recognize pathogen-associated molecular patterns (PAMPs)

Question 8

Which of the following best describes the role of fever in the innate immune response?

Accepted Answer

Fever enhances the effects of interferons and may inhibit the growth of some microbes.

Question 9

Which of the following cells is primarily responsible for releasing histamine during inflammation?

Accepted Answer

Basophils

Question 10

A researcher observes that a certain cell type can kill virally infected cells by secreting toxins, but does not attack normal body cells. Which cell type is most likely being observed?

Accepted Answer

Natural killer (NK) lymphocyte

Question 11

Which of the following best explains why sebum is important in the first line of defense?

Accepted Answer

It lowers the pH of the skin, creating an environment inhibitory to many bacteria.

Question 12

Which of the following is a function of neutrophil extracellular traps (NETs)?

Accepted Answer

They bind to and kill bacteria extracellularly.

Question 13

Which of the following is a characteristic of acute inflammation?

Accepted Answer

It develops quickly, is short-lived, and is typically beneficial.

Question 14

Which of the following best describes the role of dendritic cells in the epidermis?

Accepted Answer

They phagocytize pathogens that penetrate the skin.

Question 15

Which of the following is a direct effect of vasodilation during inflammation?

Accepted Answer

Redness and localized heat at the site of inflammation

Question 16

Which of the following statements about interferons is TRUE?

Accepted Answer

They are protein molecules released by host cells to nonspecifically inhibit the spread of viral infections.

Question 17

A patient has a wound that is not healing properly and shows signs of chronic inflammation. Which of the following is a likely consequence?

Accepted Answer

Long-term tissue damage and possible disease

Question 18

Which of the following best describes the function of NOD proteins in innate immunity?

Accepted Answer

They are cytosolic proteins that bind PAMPs and trigger inflammation and apoptosis.

Question 19

Which of the following is a plausible outcome if the lacrimal apparatus is not functioning properly?

Accepted Answer

Increased risk of bacterial eye infections due to reduced lysozyme activity in tears

Question 20

Which of the following best explains why the complement system is considered a bridge between innate and adaptive immunity?

Accepted Answer

It can be activated by both antibody-dependent (classical) and antibody-independent (alternative and lectin) pathways.

Innate Immunity: The Body’s First and Second Lines of Defense

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