Question 1

Which of the following best distinguishes innate immunity from adaptive immunity?

Accepted Answer

Innate immunity provides a rapid, non-specific response, while adaptive immunity develops slowly and is highly specific to particular antigens.

Question 2

A patient with a genetic defect that prevents the production of hematopoietic stem cells would most likely experience which of the following consequences?

Accepted Answer

A complete lack of all blood cells, including leukocytes, erythrocytes, and platelets.

Question 3

Which of the following is NOT a physical or chemical barrier to infection in a healthy adult?

Accepted Answer

Antibody production by plasma cells

Question 4

A researcher observes that a certain pathogen is unable to infect the liver but can infect the lungs. This is an example of:

Accepted Answer

Host tissue specificity

Question 5

Which of the following best describes the process of opsonization?

Accepted Answer

The coating of pathogens with molecules such as antibodies or complement proteins to enhance phagocytosis.

Question 6

Which of the following cell types is primarily responsible for mediating the innate immune response?

Accepted Answer

Phagocytes such as neutrophils and macrophages

Question 7

A patient is diagnosed with a deficiency in complement proteins. Which of the following immune processes would be most directly impaired?

Accepted Answer

Opsonization and lysis of pathogens

Question 8

Which of the following best explains why normal microbiota are important for preventing disease?

Accepted Answer

They compete with pathogens for nutrients and attachment sites, limiting pathogen colonization.

Question 9

During an inflammatory response, which of the following events occurs first?

Accepted Answer

Vasodilation and increased vascular permeability.

Question 10

A patient with a mutation in the gene encoding for major histocompatibility complex (MHC) molecules would most likely have difficulty with which immune process?

Accepted Answer

Recognition of self versus non-self antigens by T cells.

Question 11

Which of the following best describes the role of interferons in innate immunity?

Accepted Answer

They are produced in response to viral infection and limit viral spread by inducing antiviral states in neighboring cells.

Question 12

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

Accepted Answer

Chemotaxis → Adherence → Ingestion → Digestion

Question 13

A person with a genetic inability to perform phagocytosis would most likely experience which of the following?

Accepted Answer

Increased susceptibility to bacterial infections due to inability to clear pathogens.

Question 14

Which of the following is a function of the complement system in innate immunity?

Accepted Answer

Direct lysis of pathogens via the formation of the membrane attack complex ($$\mathrm{MAC}).$$

Question 15

Which of the following best describes the role of lymph nodes in the immune system?

Accepted Answer

They are sites where immune cells interact with antigens and initiate adaptive immune responses.

Question 16

A patient presents with a high fever, low blood pressure, and widespread inflammation after a bacterial infection. This clinical picture is most consistent with:

Accepted Answer

Septic shock

Question 17

Which of the following is a key difference between T-cytotoxic cells and natural killer (NK) cells?

Accepted Answer

T-cytotoxic cells require antigen presentation via MHC I molecules, while NK cells can recognize and kill cells lacking MHC I.

Question 18

Which of the following best explains why both innate and adaptive immunity are necessary for survival in a normal environment?

Accepted Answer

Innate immunity provides immediate, non-specific defense, while adaptive immunity provides long-lasting, specific protection and memory.

Question 19

Which of the following is an example of a chemical barrier to infection?

Accepted Answer

Lysozyme in tears and saliva

Question 20

A patient with a deficiency in antigen-presenting cells (APCs) would most likely have impaired:

Accepted Answer

Activation of T cells and initiation of adaptive immune responses.

Innate Immunity and Host Defenses – Study Guidance

Study Guide - Practice Questions

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