Question 1

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

Accepted Answer

Innate immunity provides a rapid, non-specific response, while adaptive immunity targets specific pathogens and has memory for faster secondary responses.

Question 2

Which cell type is primarily responsible for humoral immunity, and what is its main function?

Accepted Answer

B cells; they recognize antigens and produce antibodies.

Question 3

Which of the following cytokines is correctly matched with its function?

Accepted Answer

Interferons: interfere with viral infections of host cells

Question 4

A hapten is best described as:

Accepted Answer

A small molecule that becomes antigenic only when attached to a carrier protein.

Question 5

Which region of an antibody molecule is responsible for binding to the epitope of an antigen?

Accepted Answer

The variable (V) region

Question 6

Which class of antibody is most abundant in serum and can cross the placenta to protect the fetus?

Accepted Answer

IgG

Question 7

A patient receives an injection of preformed antibodies after exposure to rabies. What type of adaptive immunity is this?

Accepted Answer

Artificially acquired passive immunity

Question 8

Which of the following best explains why the secondary immune response is faster and more robust than the primary response?

Accepted Answer

The presence of memory B cells that rapidly differentiate into plasmocytes upon re-exposure to the antigen.

Question 9

Which outcome of antigen–antibody interaction involves coating a pathogen to enhance its uptake and destruction by phagocytes?

Accepted Answer

Opsonization

Question 10

A child is exposed to chickenpox and develops immunity after recovering. This is an example of:

Accepted Answer

Naturally acquired active immunity

Question 11

Which antibody class is primarily responsible for the initial response to an infection and is most effective at agglutinating antigens?

Accepted Answer

IgM

Question 12

Which process ensures that B cells producing antibodies against self-antigens are eliminated during development?

Accepted Answer

Clonal deletion

Question 13

Which of the following is a function of T helper (CD4+) cells?

Accepted Answer

Secreting cytokines that activate B cells and other immune cells

Question 14

A patient with a parasitic worm infection shows elevated levels of which antibody class, and what is a key function of this antibody?

Accepted Answer

IgE; triggering release of histamines and lysis of parasitic worms

Question 15

Which of the following best describes the role of natural killer (NK) cells in the immune response?

Accepted Answer

They recognize and destroy cells lacking MHC class I molecules, such as virus-infected or tumor cells.

Question 16

Which of the following is a multi-step process that results in the production of both antibody-secreting plasmocytes and memory B cells?

Accepted Answer

Clonal selection and expansion

Question 17

Which of the following best explains why IgA is important in protecting against respiratory infections?

Accepted Answer

IgA is secreted in mucous membranes, saliva, and tears, preventing microbial attachment to mucosal surfaces.

Question 18

Which of the following best describes the function of antigen-presenting cells (APCs) in adaptive immunity?

Accepted Answer

They engulf and degrade microbes, then present antigen fragments on MHC molecules to T cells.

Question 19

Which of the following is a correct sequence of events in the activation of a cytotoxic T lymphocyte (CTL)?

Accepted Answer

CTL binds to antigen presented on MHC class I, becomes activated, and releases perforin and granzymes to induce apoptosis in the target cell.

Question 20

A laboratory test detects high levels of IgM but low levels of IgG 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.

Adaptive Immunity: Specific Defenses of the Host – Study Notes

Study Guide - Practice Questions

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