Question 1

Which of the following best describes the role of the skin in the body's first line of defense against pathogens?

Accepted Answer

It acts as a physical barrier preventing the entry of bacteria, viruses, and fungi.

Question 2

Which process is primarily responsible for the movement of leukocytes from the bloodstream into infected tissues during inflammation?

Accepted Answer

Chemotaxis

Question 3

A patient presents with an increased percentage of eosinophils in their white blood cell count. Which type of infection is most likely indicated?

Accepted Answer

Parasitic worm infection

Question 4

Which of the following is NOT a function of antimicrobial peptides found in the body's second line of defense?

Accepted Answer

Directly producing antibodies against pathogens

Question 5

Which cell type is capable of diapedesis, contains granules with acidic and basic dyes, and releases inflammatory chemicals?

Accepted Answer

Neutrophils

Question 6

What is the main function of Pattern Recognition Receptors (PRRs) in innate immunity?

Accepted Answer

To identify and bind to pathogen-associated molecular patterns (PAMPs) for immune activation

Question 7

Which of the following best explains the mechanism of action for neutrophil extracellular traps (NETs)?

Accepted Answer

NETs release webs of extracellular fibers that trap and kill pathogens with antimicrobial peptides.

Question 8

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

Accepted Answer

Chemotaxis → Adhesion → Ingestion → Maturation → Killing → Elimination

Question 9

Which complement pathway is activated by antibodies bound to antigens and leads to the formation of the membrane attack complex?

Accepted Answer

Classical pathway

Question 10

A mutation in the gene encoding NOD proteins would most likely affect which aspect of innate immunity?

Accepted Answer

Recognition of viral RNA in the cytoplasm

Question 11

Which of the following is a function of the lacrimal apparatus in innate immunity?

Accepted Answer

Producing tears that contain lysozyme to destroy bacteria

Question 12

Which of the following best describes the role of siderophores in bacterial survival within the host?

Accepted Answer

They secrete iron-binding compounds to acquire iron during iron scarcity.

Question 13

Which of the following is a direct result of Toll-like receptor (TLR) activation on a phagocyte's cell membrane?

Accepted Answer

Upregulation of costimulatory molecules and enhanced antigen presentation to T cells

Question 14

Which of the following is NOT considered part of the body's first line of defense?

Accepted Answer

Phagocytic cells

Question 15

Which process involves the coating of pathogens with proteins to enhance their uptake by phagocytes?

Accepted Answer

Opsonization

Question 16

Which of the following equations correctly represents the activation of complement component C3 in the classical pathway?

Accepted Answer

$$C1 + C4 + C2 \rightarrow C3$$

Question 17

Which cell type leaves the blood and matures into macrophages, playing a key role in phagocytosis?

Accepted Answer

Monocytes

Question 18

Which of the following is a function of natural killer (NK) cells in innate immunity?

Accepted Answer

Destroying virally infected cells by releasing toxins onto their surfaces

Question 19

Which of the following is a key difference between Toll-like receptors (TLRs) and NOD proteins?

Accepted Answer

TLRs are located on the cell surface or in membranes, while NOD proteins are found in the cytoplasm.

Question 20

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

Accepted Answer

It enhances immune responses and inhibits pathogen growth.

Innate Immunity: Structure, Components, and Mechanisms

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