Question 1

Which of the following best describes the main difference between innate and adaptive immunity?

Accepted Answer

Innate immunity provides a non-specific, immediate response, while adaptive immunity provides a specific, learned response.

Question 2

A patient is infected with Streptococcus pneumoniae. Which microbial evasion strategy is this pathogen most likely using to avoid phagocytosis?

Accepted Answer

Formation of a capsule to inhibit adherence

Question 3

Which white blood cell is the first responder to bacterial infections and is most abundant in a normal blood sample?

Accepted Answer

Neutrophil

Question 4

Which of the following best describes the process of phagocytosis as shown in the first image?

Accepted Answer

Phagocytes engulf microbes, form a phagosome, fuse with a lysosome, digest the microbe, and discharge waste.

Question 5

Which of the following chemical barriers is most effective against Gram-positive bacteria?

Accepted Answer

Lysozyme

Question 6

A patient with tuberculosis is found to have Mycobacterium tuberculosis surviving inside immune cells. Which evasion mechanism is being used?

Accepted Answer

Prevention of phagosome-lysosome fusion

Question 7

Which complement pathway is triggered by antibodies bound to a pathogen, as shown in the second image?

Accepted Answer

Classical pathway

Question 8

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

Accepted Answer

Activates macrophages and neutrophils to enhance phagocytosis

Question 9

Which acute-phase protein is primarily responsible for increasing the permeability of blood vessels during inflammation?

Accepted Answer

Histamine

Question 10

A patient develops a fever after a bacterial infection. Which of the following best explains the physiological benefit of fever?

Accepted Answer

Fever helps kill pathogens and speeds up immune reactions.

Question 11

Which of the following best describes the role of opsonization in the complement system?

Accepted Answer

Opsonization tags pathogens for phagocytosis by immune cells.

Question 12

Which of the following pathogens is known for escaping from the phagosome into the cytoplasm to avoid destruction?

Accepted Answer

Shigella

Question 13

Which white blood cell type is primarily responsible for releasing histamine during allergic reactions?

Accepted Answer

Basophil

Question 14

A patient is diagnosed with Q fever, caused by Coxiella burnetii. Which microbial evasion strategy allows this pathogen to survive?

Accepted Answer

Surviving inside the phagolysosome

Question 15

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

Accepted Answer

Adherence → Ingestion → Formation of phagosome → Fusion with lysosome → Digestion → Discharge

Question 16

Which complement pathway is activated by mannose-binding lectin (MBL) binding to carbohydrates on a pathogen surface?

Accepted Answer

Lectin pathway

Question 17

Which of the following is a function of prostaglandins during inflammation?

Accepted Answer

Increase permeability of blood vessels and intensify the effects of histamine and kinins

Question 18

Which of the following best explains why Salmonella can evade the complement system?

Accepted Answer

It has surface lipid-carbohydrates that prevent membrane attack complex (MAC) formation.

Question 19

Which of the following equations best represents the process of oxygen transport by erythrocytes?

Accepted Answer

$$\mathrm{Hb} + \mathrm{O}_2 \rightarrow \mathrm{HbO}_2$$

Innate Immunity: Mechanisms and Cellular Components

Study Guide - Practice Questions