Question 1

Which of the following is a primary mechanism by which protozoa cause disease in humans?

Accepted Answer

They digest host cells, leading to tissue damage.

Question 2

A patient presents with a topical infection that resists phagocytosis. Which microbial feature is most likely responsible for this resistance?

Accepted Answer

Presence of a capsule

Question 3

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

Accepted Answer

TLRs recognize Pathogen-Associated Molecular Patterns (PAMPs) and trigger cytokine release.

Question 4

Which portal of exit is most commonly associated with the transmission of respiratory viruses?

Accepted Answer

Coughing and sneezing via the respiratory tract

Question 5

A laboratory test shows a patient's white blood cell count is $$3,800$$ cells per microliter. Which of the following is the most likely explanation?

Accepted Answer

The patient is likely suffering from a viral infection.

Question 6

Which of the following chemical factors contributes to the skin's ability to inhibit microbial growth?

Accepted Answer

Sebum creating an acidic pH of $$3-5$$

Question 7

Which statement best distinguishes innate immunity from adaptive immunity?

Accepted Answer

Innate immunity is immediate and non-specific, while adaptive immunity is specific and has memory.

Question 8

A patient ingests contaminated food. Which first line of defense is most likely to destroy the ingested microbes?

Accepted Answer

Gastric juice with a pH of $$1.2-3.0$$

Question 9

Which of the following is NOT a physical factor in the body's first line of defense?

Accepted Answer

Lysozyme in tears

Question 10

Interferons alpha and beta are produced by cells in response to which type of infection?

Accepted Answer

Viral infection

Question 11

Which of the following best explains why helminth infections can cause significant physical damage to host tissues?

Accepted Answer

Helminths use host tissue for growth and their large size causes cellular damage.

Question 12

A patient is exposed to a pathogen with lipopolysaccharide (LPS) in its cell wall. Which immune component is most likely to recognize this molecule?

Accepted Answer

Toll-like receptors (TLRs)

Question 13

Which of the following is a plausible consequence of a fungal infection that produces proteases?

Accepted Answer

Modification of host cell membranes, compromising their integrity

Question 14

Which of the following best describes the function of lysozyme?

Accepted Answer

Lysozyme breaks down bacterial cell walls.

Question 15

A patient with a high white blood cell count ($$15,000$$ cells per microliter) is most likely suffering from which condition?

Accepted Answer

A bacterial infection or autoimmune disease

Question 16

Which of the following is a characteristic of adaptive immunity that distinguishes it from innate immunity?

Accepted Answer

It has a memory component, allowing for faster responses upon re-exposure.

Question 17

Which of the following is an example of a mechanical defense in the first line of innate immunity?

Accepted Answer

Vomiting

Question 18

A patient is exposed to a pathogen via a mosquito bite. Which portal of entry is involved?

Accepted Answer

Arthropod vector

Question 19

Which of the following is a function of cytokines released during the innate immune response?

Accepted Answer

Acting as alarm signals to recruit other immune cells

Question 20

Which of the following is a major difference between humoral and cellular immunity within the adaptive immune system?

Accepted Answer

Humoral immunity is mediated by antibodies, while cellular immunity is mediated by cells.

Innate and Adaptive Immunity: Mechanisms, Barriers, and Host Defense

Study Guide - Practice Questions