Question 1

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

Accepted Answer

Innate immunity is present at birth and acts rapidly, while adaptive immunity develops more slowly and has memory.

Question 2

A patient presents with a high fever, low blood pressure, and rapid heart rate after a bacterial infection. Which immune process is most likely contributing to their condition?

Accepted Answer

Overactivation of the complement system leading to septic shock.

Question 3

Which of the following is a function of Toll-like receptors (TLRs) in innate immunity?

Accepted Answer

TLRs recognize pathogen-associated molecular patterns (PAMPs) and trigger cytokine release.

Question 4

Which physical factor is most important in preventing microbial entry through the respiratory tract?

Accepted Answer

The ciliary escalator moving mucus and trapped microbes away from the lungs.

Question 5

What is the main role of normal microbiota in innate immunity?

Accepted Answer

They compete with pathogens for space and nutrients, and may produce substances harmful to pathogens.

Question 6

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

Accepted Answer

Sebum forming a protective film and lowering pH.

Question 7

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

Accepted Answer

Increased susceptibility to infections.

Question 8

Which of the following best describes the process of opsonization?

Accepted Answer

Microorganisms are coated with serum proteins, making them easier for phagocytes to ingest.

Question 9

Which white blood cell type is most abundant in normal blood and is primarily responsible for early phagocytic response to infection?

Accepted Answer

Neutrophils

Question 10

During inflammation, what is the primary cause of redness and heat at the site of injury?

Accepted Answer

Vasodilation and increased blood flow to the area.

Question 11

Which of the following is NOT a typical sign or symptom of inflammation?

Accepted Answer

Fever

Question 12

Which pathway of complement activation is triggered by antibodies binding to antigens?

Accepted Answer

Classical pathway

Question 13

What is the main function of interferons (IFN-α and IFN-β) in the immune response?

Accepted Answer

They cause neighboring cells to produce antiviral proteins that inhibit viral replication.

Question 14

Which of the following best explains why lymph nodes swell during an infection?

Accepted Answer

Accumulation of lymphocytes and macrophages responding to pathogens.

Question 15

A patient with a respiratory infection has impaired ciliary escalator function. What is a likely consequence?

Accepted Answer

Increased risk of microbes reaching the lungs and causing infection.

Question 16

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

Accepted Answer

Chemotaxis → Adherence → Ingestion → Digestion

Question 17

Which of the following is a role of iron-binding proteins in innate immunity?

Accepted Answer

They bind iron, making it unavailable to microbes and limiting their growth.

Question 18

A child with sickle cell trait is less susceptible to malaria caused by Plasmodium falciparum. This is an example of:

Accepted Answer

Genetic resistance providing a selective survival advantage.

Question 19

Which of the following is a consequence of complement activation?

Accepted Answer

Cytolysis, opsonization, and inflammation.

Question 20

Which of the following best describes the role of antimicrobial peptides in innate immunity?

Accepted Answer

They inhibit cell wall synthesis and form pores in microbial membranes.

Innate Immunity: Nonspecific Defenses of the Host

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