Question 1

Which of the following best describes the primary difference between humoral and cellular immunity in the adaptive immune system?

Accepted Answer

Humoral immunity produces antibodies to combat antigens outside cells, while cellular immunity uses T lymphocytes to target antigens inside infected cells.

Question 2

A patient is exposed to a virus for the first time. Which immunoglobulin class is most likely to be produced first in response to this infection?

Accepted Answer

IgM

Question 3

Which of the following statements about IgG is CORRECT?

Accepted Answer

IgG crosses the placenta and provides passive immunity to the fetus.

Question 4

A laboratory technician observes agglutination when mixing a patient's serum with a bacterial suspension. Which immunoglobulin is most likely responsible for this reaction?

Accepted Answer

IgM

Question 5

Which process ensures that B cells which react against self-antigens are eliminated during development?

Accepted Answer

Clonal deletion

Question 6

A child receives antibodies against hepatitis B through an injection. What type of adaptive immunity is this?

Accepted Answer

Artificially acquired passive immunity

Question 7

Which of the following is a function of cytokines in the immune response?

Accepted Answer

They serve as protein messengers that regulate the activity and communication of immune cells.

Question 8

Which cell type is primarily responsible for presenting antigens to T cells in the skin and lymph nodes?

Accepted Answer

Dendritic cells

Question 9

A patient with a parasitic worm infection shows elevated levels of a certain immunoglobulin. Which immunoglobulin is most likely elevated?

Accepted Answer

IgE

Question 10

Which of the following best explains the concept of 'memory' in the adaptive immune system?

Accepted Answer

The rapid and enhanced response to a previously encountered antigen due to the presence of memory cells.

Question 11

Which of the following is TRUE regarding the structure of a typical antibody?

Accepted Answer

It consists of two identical heavy chains and two identical light chains joined by disulfide bonds.

Question 12

Which immune process involves tagging pathogens for enhanced phagocytosis by immune cells?

Accepted Answer

Opsonization

Question 13

A patient with an autoimmune disease is found to have excessive production of TNF-alpha. What is the most likely consequence?

Accepted Answer

Increased inflammation

Question 14

Which of the following best describes the role of MHC class I molecules?

Accepted Answer

They identify a cell as 'self' and present endogenous antigens to cytotoxic T cells (CD8+).

Question 15

Which of the following is a correct sequence of events in the activation of B cells against a T-dependent antigen?

Accepted Answer

B cell binds antigen, internalizes and processes it, presents antigen fragment on MHC class II, T helper cell releases cytokines, B cell undergoes clonal expansion.

Question 16

Which immunoglobulin class is most abundant in secretions such as saliva, tears, and breast milk, and helps prevent microbial attachment to mucous membranes?

Accepted Answer

IgA

Question 17

A researcher is studying the diversity of antibodies produced by an individual. Which genetic mechanism is responsible for generating this diversity?

Accepted Answer

Rearrangement of immunoglobulin gene segments in the antigen-binding region

Question 18

Which cell type is responsible for killing virus-infected cells by releasing perforin and granzymes, leading to apoptosis?

Accepted Answer

Cytotoxic T lymphocytes (CD8+)

Question 19

A patient is exposed to the same antigen for a second time. Which of the following best describes the antibody response?

Accepted Answer

The response is more rapid, greater in magnitude, and involves class switching to IgG, IgA, or IgE.

Question 20

Which of the following is TRUE regarding natural killer (NK) cells?

Accepted Answer

They destroy virus-infected cells and tumor cells by detecting the absence of MHC class I molecules.

Adaptive Immunity: Specific Defenses of the Host (Chapter 17 Study Notes)

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