Question 1

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

Accepted Answer

The innate immune system provides a rapid, nonspecific response, while the adaptive immune system provides a slower, specific response with memory.

Question 2

A patient receives a kidney transplant from a genetically unrelated donor. Which type of graft is this, and what is the main immune concern?

Accepted Answer

Allograft; risk of immune rejection due to T cell activation

Question 3

Which of the following is NOT a function of inflammation?

Accepted Answer

Directly produces antibodies to neutralize pathogens

Question 4

Which cell type is primarily responsible for the production of antibodies in the humoral immune response?

Accepted Answer

Plasma cells

Question 5

A person is exposed to a new strain of influenza virus. Which process allows their adaptive immune system to respond more rapidly upon a second exposure?

Accepted Answer

Clonal selection and formation of memory cells

Question 6

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

Accepted Answer

Fever increases the metabolic rate of tissue cells, speeding up repair processes.

Question 7

Which of the following is a correct sequence of events in phagocyte mobilization during acute inflammation?

Accepted Answer

Leukocytosis → Margination → Diapedesis → Chemotaxis

Question 8

Which of the following best describes the role of opsonization in the immune response?

Accepted Answer

It coats pathogens with complement proteins or antibodies to enhance phagocytosis.

Question 9

A patient develops muscle weakness and is diagnosed with myasthenia gravis. Which type of immune system malfunction is responsible?

Accepted Answer

Autoimmune disease

Question 10

Which of the following is a characteristic of a complete antigen?

Accepted Answer

It can stimulate proliferation of specific lymphocytes and react with them.

Question 11

Which of the following best describes the mechanism by which cytotoxic T cells kill infected cells?

Accepted Answer

They release perforins and granzymes to induce apoptosis.

Question 12

A child is born with a genetic defect resulting in a lack of both B and T cells. Which condition does this describe, and what is the primary consequence?

Accepted Answer

Severe Combined Immunodeficiency (SCID); increased susceptibility to infections

Question 13

Which of the following is a function of regulatory T cells (Tregs)?

Accepted Answer

They suppress self-reactive lymphocytes to prevent autoimmune reactions.

Question 14

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

Accepted Answer

Receiving antivenom after a snake bite

Question 15

Which of the following best explains why the skin is an effective barrier against infection?

Accepted Answer

It contains multiple layers of tightly packed cells and keratin, which resists penetration and chemical damage.

Question 16

Which of the following hypersensitivity reactions is mediated by T cells and occurs 48 hours after exposure?

Accepted Answer

Type IV (delayed) hypersensitivity

Question 17

Which of the following best describes the role of Toll-like receptors (TLRs) in innate immunity?

Accepted Answer

They recognize specific classes of microbial molecules and trigger inflammatory signaling.

Question 18

Which of the following is a correct statement about active and passive immunity?

Accepted Answer

Active and passive humoral immunity are both mechanisms of adaptive immunity that use antibodies.

Question 19

A patient with a history of rheumatic fever develops heart valve damage due to cross-reactivity of antibodies. Which mechanism best explains this autoimmune phenomenon?

Accepted Answer

Foreign antigens resemble self-antigens, leading to cross-reactivity.

Question 20

Which of the following equations best represents the relationship between antigen exposure and antibody titer in a secondary immune response?

Accepted Answer

$$A_{titer,secondary} \u003e A_{titer,primary}$$

The Immune System: Innate and Adaptive Body Defenses

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