Question 1

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

Accepted Answer

It destroys the cell walls of microbes by hydrolyzing peptidoglycan.

Question 2

A patient with a genetic defect resulting in nonfunctional C3 protein would most likely have which of the following immune deficiencies?

Accepted Answer

Defective opsonization, cytolysis, and inflammation responses.

Question 3

Which of the following is NOT a physical factor involved in the first line of defense against pathogens?

Accepted Answer

Sebum production

Question 4

A laboratory test shows a patient has an abnormally high percentage of eosinophils. This finding is most consistent with which of the following conditions?

Accepted Answer

A parasitic worm infection

Question 5

Which of the following best explains why Helicobacter pylori can survive in the stomach, while most other bacteria cannot?

Accepted Answer

It neutralizes stomach acidity, allowing it to grow in low pH environments.

Question 6

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

Accepted Answer

Chemotaxis → Adherence → Ingestion → Digestion

Question 7

A Gram-negative bacterial infection triggers fever in a patient. Which of the following best describes the sequence of events leading to fever?

Accepted Answer

Endotoxin stimulates phagocytes to release interleukin-1, which causes the hypothalamus to release prostaglandins, raising body temperature.

Question 8

Which of the following is a function of the membrane attack complex (MAC) formed during complement activation?

Accepted Answer

Directly lysing microbial cell membranes

Question 9

Which of the following best describes the role of normal microbiota in nonspecific immunity?

Accepted Answer

They compete with pathogens for nutrients and space, inhibiting pathogen growth.

Question 10

A patient is infected with Streptococcus pneumoniae, which has a capsule. Which mechanism does this bacterium use to evade the host's nonspecific defenses?

Accepted Answer

Inhibiting adherence of phagocytes

Question 11

Which of the following chemical mediators is primarily responsible for vasodilation and increased permeability of blood vessels during inflammation?

Accepted Answer

Histamine

Question 12

Which of the following is NOT a cardinal sign of inflammation?

Accepted Answer

Leukocytosis

Question 13

Which pathway of complement activation is initiated by antigen-antibody complexes?

Accepted Answer

Classical pathway

Question 14

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

Accepted Answer

It enhances the activity of interferons and inhibits the growth of some microbes.

Question 15

Which of the following is a correct match between a white blood cell and its function?

Accepted Answer

Eosinophil – counterattack against parasitic worms

Question 16

Which of the following is a chemical factor that inhibits microbial growth on the skin?

Accepted Answer

Sebum containing unsaturated fatty acids

Question 17

A patient with a deficiency 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 18

Which of the following is a function of interferon-gamma (IFN-$$ \gamma $$)?

Accepted Answer

Activates neutrophils and macrophages to kill bacteria by phagocytosis

Question 19

Which of the following best describes the process of opsonization?

Accepted Answer

The coating of a microorganism with serum proteins to enhance phagocytosis

Question 20

A patient with a severe burn loses large areas of skin. Which of the following best explains why this patient is at increased risk for infection?

Accepted Answer

Loss of the skin removes a major physical barrier and chemical defense (keratin, sebum) against pathogens.

BIO108 Chapter 16 Non-Specific Immunity

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