Question 1

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

Accepted Answer

Innate immunity is present at birth and responds rapidly to any pathogen, while adaptive immunity develops more slowly and targets specific pathogens.

Question 2

A patient presents with a high white blood cell (WBC) count. Which of the following is the most likely cause?

Accepted Answer

Autoimmune disease

Question 3

Which of the following is a physical factor that prevents microbial entry through the respiratory tract?

Accepted Answer

Ciliary escalator

Question 4

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 5

Which of the following is NOT a function of normal microbiota in innate immunity?

Accepted Answer

Directly producing antibodies against pathogens

Question 6

Which leukocyte is most abundant in normal blood and is the first to respond to a bacterial infection?

Accepted Answer

Neutrophil

Question 7

During phagocytosis, what is the role of opsonization?

Accepted Answer

It coats the microbe with serum proteins to enhance adherence by phagocytes.

Question 8

Which of the following chemical mediators is primarily responsible for vasodilation during inflammation?

Accepted Answer

Histamine

Question 9

A patient with a genetic deficiency in complement proteins would most likely experience which of the following?

Accepted Answer

Increased susceptibility to infections

Question 10

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

Accepted Answer

Fever inhibits multiplication of temperature-sensitive microorganisms and enhances immune responses.

Question 11

Which pathway of complement activation is triggered directly by repeating molecules on microbial surfaces, such as LPS?

Accepted Answer

Alternative pathway

Question 12

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

Accepted Answer

Chemotaxis → Adherence → Ingestion → Digestion → Excretion

Question 13

Which of the following is a function of interferons (IFNs) in innate immunity?

Accepted Answer

Inducing neighboring cells to produce antiviral proteins that inhibit viral replication

Question 14

A patient with a severe bacterial infection develops swelling, redness, heat, and pain at the site of infection. Which process is primarily responsible for these signs?

Accepted Answer

Inflammation

Question 15

Which of the following best describes the role of iron-binding proteins in innate immunity?

Accepted Answer

They bind iron tightly, limiting its availability to pathogens.

Question 16

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

Accepted Answer

It forms transmembrane channels that cause cytolysis of target cells.

Question 17

Which of the following is an example of a chemical factor that prevents microbial growth on the skin?

Accepted Answer

Sebum

Question 18

Which of the following best describes the process of diapedesis?

Accepted Answer

The squeezing of phagocytes between endothelial cells of blood vessels to reach infected tissue

Question 19

Which of the following is a benefit of edema during inflammation?

Accepted Answer

It dilutes toxic substances and brings clotting factors to the site of injury.

Question 20

Which of the following antimicrobial peptides is produced by neutrophils and macrophages and can form pores in microbial membranes?

Accepted Answer

Defensins

Innate Immunity: Nonspecific Defenses of the Host – Study Notes

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