Question 1

Which of the following best explains how lysozyme acts as an antimicrobial substance in the innate immune response?

Accepted Answer

It hydrolyzes the peptidoglycan layer in bacterial cell walls, leading to cell lysis.

Question 2

A patient with a genetic defect in peroxidase production is more susceptible to certain infections. Which of the following best describes the role of peroxidase in innate immunity?

Accepted Answer

It catalyzes the formation of reactive oxygen species that are toxic to microbes.

Question 3

Which of the following is NOT a function of normal flora in the first line of defense?

Accepted Answer

Directly phagocytosing invading microbes.

Question 4

Which of the following best describes the process of hematopoiesis?

Accepted Answer

The formation and development of blood cells from stem cells in the bone marrow.

Question 5

A laboratory test shows a patient has a deficiency in neutrophils. Which function would be most directly impaired?

Accepted Answer

Phagocytosis of bacteria at sites of acute infection.

Question 6

Which of the following best describes the role of chemokines in the immune response?

Accepted Answer

They direct the migration of immune cells to sites of infection or injury.

Question 7

Which of the following is a correct statement about the classical pathway of the complement system?

Accepted Answer

It is initiated by the binding of antibodies to antigens on the surface of a pathogen.

Question 8

Which of the following is NOT a protective outcome of complement activation?

Accepted Answer

Inhibition of antibody production by B cells.

Question 9

A patient presents with redness, heat, swelling, and pain at a wound site. Which of the following best explains the physiological reason for the swelling?

Accepted Answer

Increased permeability of blood vessels allows fluid and proteins to enter the tissue.

Question 10

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

Accepted Answer

They recognize conserved microbial molecules and trigger intracellular signaling pathways that activate immune responses.

Question 11

Which of the following cytokines is primarily responsible for inducing fever during an infection?

Accepted Answer

Interleukin-1 (IL-1)

Question 12

Which of the following best explains how fever inhibits the growth of pathogens?

Accepted Answer

It raises body temperature above the optimal range for microbial enzymes, slowing their growth.

Question 13

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

Accepted Answer

Chemotaxis $$ \rightarrow $$ recognition and attachment $$ \rightarrow $$ engulfment $$ \rightarrow $$ phagolysosome formation $$ \rightarrow $$ digestion $$ \rightarrow $$ exocytosis

Question 14

Which of the following best describes the function of lactoferrin in the innate immune response?

Accepted Answer

It binds iron, making it unavailable to microbes and inhibiting their growth.

Question 15

A patient is exposed to a bacterial endotoxin that triggers the release of tumor necrosis factor (TNF). Which of the following is a likely effect of TNF in this scenario?

Accepted Answer

Induction of inflammation and promotion of apoptosis in infected cells.

Question 16

Which of the following is a distinguishing feature of the alternative pathway of complement activation?

Accepted Answer

It is triggered by spontaneous hydrolysis of C3 in the absence of antibodies.

Question 17

Which of the following best describes apoptosis in the context of the immune response?

Accepted Answer

A programmed cell death process that eliminates infected or damaged cells without causing inflammation.

Question 18

Which of the following is NOT one of the four cardinal signs of inflammation?

Accepted Answer

Numbness (anesthesia)

Question 19

Which of the following is a possible stimulus for inflammation?

Accepted Answer

All of the above

Question 20

A researcher is studying the effect of defensins on bacterial populations. Which of the following best describes the action of defensins?

Accepted Answer

They insert into microbial membranes, forming pores that disrupt membrane integrity.

Innate Immune Response Study Guide – Microbiology

Study Guide - Practice Questions

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