Question 1

Which of the following best describes the difference between the primary and secondary adaptive immune responses?

Accepted Answer

The primary response is slower and produces low levels of antibody, while the secondary response is faster and produces high levels of antibody due to memory cells.

Question 2

Which immunoglobulin class is most effective at agglutinating antigens and is the first antibody produced during a primary immune response?

Accepted Answer

Immunoglobulin M (IgM)

Question 3

A newborn is protected from gastrointestinal infections primarily by which immunoglobulin, and how is it acquired?

Accepted Answer

IgA, acquired through breast milk

Question 4

Which of the following best explains why a person vaccinated against smallpox is also protected against cowpox?

Accepted Answer

Smallpox and cowpox share closely related antigens, allowing cross-protection.

Question 5

Which of the following is NOT a function of antibodies?

Accepted Answer

Direct lysis of infected host cells

Question 6

What is the role of the Fc (constant) region of an antibody?

Accepted Answer

It binds complement proteins and phagocytes.

Question 7

Which cell type is responsible for presenting antigens to T helper cells and initiating the adaptive immune response?

Accepted Answer

Antigen presenting cells (APCs) such as macrophages, dendritic cells, and B cells

Question 8

A patient receives an injection of pre-formed antibodies after a snake bite. This is an example of:

Accepted Answer

Passive, artificially acquired immunity

Question 9

Which of the following best describes the process of clonal expansion in the adaptive immune response?

Accepted Answer

A single B cell divides and differentiates into plasma cells and memory cells after activation by a specific antigen.

Question 10

Which immunoglobulin class is most abundant in blood and can cross the placenta to provide passive immunity to the fetus?

Accepted Answer

IgG

Question 11

Which of the following best describes the role of cytotoxic T cells (TC cells) in the immune response?

Accepted Answer

They lyse infected or abnormal host cells by releasing perforins.

Question 12

Which of the following is TRUE regarding the antigen-binding site of an antibody?

Accepted Answer

It is identical on both arms of the antibody molecule.

Question 13

A patient with a deficiency in helper T cells would most likely have problems with which aspect of immunity?

Accepted Answer

Both antibody-mediated and cell-mediated immunity

Question 14

Which of the following best explains why passive immunity does not result in long-term protection?

Accepted Answer

Passive immunity does not generate memory cells.

Question 15

Which of the following scenarios is an example of active, naturally acquired immunity?

Accepted Answer

A person recovers from measles after infection.

Question 16

Which process involves the antibody binding to a toxin or virus, preventing it from interacting with host cells?

Accepted Answer

Neutralization

Question 17

Which of the following best describes the role of MHC molecules in the adaptive immune response?

Accepted Answer

They present antigen fragments to T cells for recognition.

Question 18

Which immunoglobulin class is primarily responsible for mediating allergic reactions by binding to mast cells and basophils?

Accepted Answer

IgE

Question 19

A laboratory test detects high levels of IgM in a patient's serum. What does this most likely indicate?

Accepted Answer

The patient is in the early stages of a primary immune response.

Question 20

Which of the following best describes the process of opsonization?

Accepted Answer

Antibodies bind to antigens, flagging them for phagocytosis by immune cells.

The Adaptive Immune Response: Mechanisms and Components

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