Question 1

Which of the following is NOT considered a physical barrier to infection in the human body?

Accepted Answer

Basophil granules

Question 2

During phagocytosis, which process involves coating a microorganism with serum proteins to enhance ingestion?

Accepted Answer

Opsonization

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 equation correctly represents the production of hydrogen peroxide ($H_2O_2$) by phagocyte enzymes during the respiratory burst?

Accepted Answer

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

Question 5

Which pathogen evasion strategy is used by Streptococcus pyogenes to avoid phagocytosis?

Accepted Answer

Inhibition of adherence via M protein and capsules

Question 6

Which cell type is primarily responsible for presenting antigens to trigger adaptive immunity?

Accepted Answer

Macrophages

Question 7

Toll-like receptors (TLRs) are important for pathogen recognition. Which TLR is most likely to recognize lipopolysaccharide (LPS) from Gram-negative bacteria?

Accepted Answer

TLR4

Question 8

Which of the following is a direct outcome of complement activation?

Accepted Answer

All of the above

Question 9

A patient is infected with HIV. Which cell surface protein does HIV primarily target for entry into host cells?

Accepted Answer

CD4

Question 10

Which of the following best describes the role of Natural Killer (NK) cells in innate immunity?

Accepted Answer

They detect and kill unhealthy cells using activating and inhibitory receptors

Question 11

Which iron-binding protein is found in milk, saliva, and mucus, and helps limit microbial growth by sequestering iron?

Accepted Answer

Lactoferrin

Question 12

Which acute-phase protein is released during inflammation and causes vasodilation and increased permeability of blood vessels?

Accepted Answer

Histamine

Question 13

Which of the following is a function of eosinophils in the innate immune response?

Accepted Answer

Release of enzymes to combat parasitic infections

Question 14

Which step in the mechanism of phagocytosis involves the movement of phagocytes toward a site of infection in response to chemical signals?

Accepted Answer

Chemotaxis

Question 15

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

Accepted Answer

It inhibits the growth of some pathogens and enhances immune cell activity

Question 16

Which of the following is a broad-spectrum antimicrobial molecule produced by epithelial cells in response to microbial invasion?

Accepted Answer

Antimicrobial peptides

Question 17

Which of the following pathogens is able to survive inside the phagolysosome, evading destruction by phagocytes?

Accepted Answer

Coxiella burnetii

Question 18

Which of the following is a correct description of the role of pattern recognition receptors (PRRs) in innate immunity?

Accepted Answer

PRRs recognize pathogen-associated molecular patterns (PAMPs) on microbes

Question 19

Which of the following is a direct effect of alpha and beta interferons (IFNs) on viral infections?

Accepted Answer

They induce neighboring cells to produce antiviral proteins

Question 20

A patient is diagnosed with HIV and begins HAART therapy. Which of the following is a primary goal of HAART?

Accepted Answer

Decrease plasma viral load

Innate Immune Response: Mechanisms, Cells, and Pathogen Interactions

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