Question 1

Which of the following best describes the primary function of physical barriers in the innate immune response?

Accepted Answer

They prevent the entry of pathogens by providing a mechanical and chemical shield.

Question 2

Which of the following is NOT a step in the mechanism of phagocytosis?

Accepted Answer

Antibody production

Question 3

A patient with cystic fibrosis is more susceptible to respiratory infections due to which defect in their innate immune system?

Accepted Answer

Impaired ciliary elevator function

Question 4

Which of the following pathogens can prevent phagosome-lysosome fusion, allowing it to survive inside phagocytes?

Accepted Answer

HIV

Question 5

Which white blood cell type is primarily responsible for releasing histamine and stimulating the inflammatory response?

Accepted Answer

Basophil

Question 6

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

Accepted Answer

They recognize pathogen-associated molecular patterns (PAMPs) and initiate immune signaling.

Question 7

Which of the following is a correct equation for the production of hydrogen peroxide ($$H_2O_2) by $$phagocyte enzymes?

Accepted Answer

$$2O_2^- + 2H^+ \rightarrow H_2O_2 + O_2$

Question 8

Which of the following is a function of Natural Killer (NK) cells in innate immunity?

Accepted Answer

They recognize and kill virus-infected or cancerous cells by detecting changes in surface molecules.

Question 9

Which of the following statements about the complement system is TRUE?

Accepted Answer

It can lead to opsonization, inflammation, and cytolysis of pathogens.

Question 10

A patient is infected with a bacterium that produces a capsule. Which mechanism is this bacterium using to evade the innate immune response?

Accepted Answer

Inhibiting adherence by preventing phagocyte attachment

Question 11

Which of the following best describes the action of alpha and beta interferons (IFNs) in antiviral defense?

Accepted Answer

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

Question 12

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

Accepted Answer

Lactoferrin

Question 13

Which of the following is a direct effect of acute-phase proteins released during inflammation?

Accepted Answer

Increased vasodilation and permeability of blood vessels

Question 14

Which of the following best explains why HIV infection leads to immunodeficiency?

Accepted Answer

HIV destroys CD4+ T cells, impairing both innate and adaptive immune responses.

Question 15

Which of the following is a correct sequence of events in the HIV replication cycle?

Accepted Answer

Attachment, fusion, reverse transcription, integration, transcription, assembly, budding

Question 16

Which of the following is a function of antimicrobial peptides in innate immunity?

Accepted Answer

Inhibit cell wall synthesis and form pores in microbial membranes

Question 17

A patient with a genetic defect in Toll-like receptor 4 (TLR4) would have difficulty recognizing which of the following pathogen-associated molecular patterns (PAMPs)?

Accepted Answer

Lipopolysaccharide (LPS)

Question 18

Which of the following best describes the role of opsonization in phagocytosis?

Accepted Answer

Coating of pathogens with serum proteins to enhance phagocyte attachment and ingestion

Question 19

Which of the following is a plausible outcome if a pathogen produces siderophores in the human body?

Accepted Answer

The pathogen can compete with host iron-binding proteins, enhancing its survival.

Question 20

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

Accepted Answer

Fever increases the activity of immune cells and inhibits the growth of some pathogens.

Innate Immune Response: Mechanisms, Cells, and HIV Pathogenesis

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