Question 1

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

Accepted Answer

The innate immune system provides immediate, nonspecific defense, while the adaptive immune system targets specific antigens and has memory.

Question 2

Which of the following is NOT a function of inflammation?

Accepted Answer

Directly produces antibodies to neutralize pathogens

Question 3

A patient receives a flu vaccine and later develops immunity to the flu virus. This is an example of which type of humoral immunity?

Accepted Answer

Artificially acquired active immunity

Question 4

Which antibody class is most abundant in plasma and can cross the placental barrier to provide passive immunity to the fetus?

Accepted Answer

IgG

Question 5

Which process enhances phagocytosis by marking pathogens with antibodies or complement proteins?

Accepted Answer

Opsonization

Question 6

A person is stung by a bee and develops anaphylactic shock within minutes. Which type of hypersensitivity reaction is this?

Accepted Answer

Type I (immediate) hypersensitivity

Question 7

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

Accepted Answer

Fever increases the metabolic rate, which accelerates tissue repair and causes the liver and spleen to sequester iron and zinc.

Question 8

Which cell type is responsible for directly killing virus-infected cells and cancer cells by releasing perforins and granzymes?

Accepted Answer

Cytotoxic T cells (TC)

Question 9

Which of the following is a key difference between Class I and Class II MHC proteins?

Accepted Answer

Class I MHC proteins present endogenous antigens to CD8 cells, while Class II MHC proteins present exogenous antigens to CD4 cells.

Question 10

A patient with a genetic defect in adenosine deaminase (ADA) enzyme has a marked deficit in both B and T cells. What is the most likely diagnosis?

Accepted Answer

Severe combined immunodeficiency (SCID) syndrome

Question 11

Which of the following best describes the role of helper T cells (TH) in the immune response?

Accepted Answer

They activate both humoral and cellular immunity by stimulating B cells and cytotoxic T cells.

Question 12

Which of the following is a characteristic of a secondary immune response compared to a primary immune response?

Accepted Answer

It produces higher levels of antibodies more rapidly due to memory cells.

Question 13

Which antibody class is primarily found in mucus and other secretions and helps prevent entry of pathogens?

Accepted Answer

IgA

Question 14

Which of the following is an example of naturally acquired passive immunity?

Accepted Answer

Antibodies passed from mother to fetus via placenta

Question 15

Which of the following best describes the process of clonal selection in B cells?

Accepted Answer

A B cell binds to its specific antigen, proliferates, and differentiates into plasma cells and memory cells.

Question 16

Which of the following is a function of regulatory T cells?

Accepted Answer

They dampen the immune response and help prevent autoimmune reactions.

Question 17

A patient receives a mismatched blood transfusion and develops a reaction involving antibody-mediated lysis of red blood cells. Which type of hypersensitivity is this?

Accepted Answer

Type II (cytotoxic) hypersensitivity

Question 18

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

Accepted Answer

It sweeps foreign material into lymphatic vessels for processing in lymph nodes.

Question 19

Which of the following best describes the mechanism of action of interferons?

Accepted Answer

They are secreted by virus-infected cells and stimulate neighboring cells to produce proteins that block viral replication.

The Immune System: Innate and Adaptive Body Defenses

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