Question 1

Which of the following best distinguishes between humoral and cellular immunity?

Accepted Answer

Humoral immunity targets extracellular pathogens using antibodies, while cellular immunity targets infected or abnormal cells directly using lymphocytes.

Question 2

A patient receives a kidney transplant and later experiences organ rejection. Which immune system component is primarily responsible for recognizing the foreign tissue?

Accepted Answer

T lymphocytes recognizing non-self MHC proteins on the transplanted organ.

Question 3

Which of the following statements about immunocompetence is correct?

Accepted Answer

Immunocompetence is the ability of a lymphocyte to recognize one specific antigen by binding to it.

Question 4

Which of the following best describes the role of antigen-presenting cells (APCs) in the adaptive immune response?

Accepted Answer

APCs engulf antigens and present fragments on their surface to T cells, initiating the adaptive immune response.

Question 5

A small molecule, such as a drug, does not elicit an immune response unless it binds to a host protein. What is this molecule called?

Accepted Answer

A hapten

Question 6

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

Accepted Answer

The secondary response is faster and produces higher levels of antibodies due to memory cells.

Question 7

Which of the following best explains why T lymphocytes require antigens to be presented on MHC proteins?

Accepted Answer

T lymphocytes can only recognize antigens that are displayed on MHC proteins, ensuring self-tolerance and specificity.

Question 8

During the maturation of lymphocytes, which process ensures that they do not react to self-antigens?

Accepted Answer

Self-tolerance

Question 9

Which of the following is TRUE regarding the origin and maturation of B and T lymphocytes?

Accepted Answer

Both B and T lymphocytes originate in the red bone marrow, but B cells mature in the bone marrow while T cells mature in the thymus.

Question 10

A patient is exposed to a pathogen for the first time. Which of the following best describes the expected immune response?

Accepted Answer

There will be a lag period of 3 to 6 days before significant antibody production occurs.

Question 11

Which of the following best describes the function of memory cells in the immune system?

Accepted Answer

They enable a faster and more effective response upon re-exposure to the same antigen.

Question 12

Which of the following is a function of activated macrophages in the immune response?

Accepted Answer

They become voracious phagocytic killers and trigger powerful inflammatory responses.

Question 13

Which of the following best explains the diversity of antigen receptors on lymphocytes?

Accepted Answer

Gene segments are shuffled by somatic recombination, allowing for billions of different antigen receptors.

Question 14

A patient with a genetic defect in MHC protein expression would most likely experience which of the following?

Accepted Answer

Impaired T cell recognition of antigens, leading to increased susceptibility to infections.

Question 15

Which of the following is the correct sequence of steps in the activation and differentiation of B cells?

Accepted Answer

Antigen binds to B cell receptor $$\rightarrow$$ receptor-mediated endocytosis $$\rightarrow$$ clonal selection $$\rightarrow$$ proliferation and differentiation into plasma and memory cells

Question 16

Which of the following best describes the role of dendritic cells in the immune system?

Accepted Answer

They act as mobile sentinels in boundary tissues, phagocytize pathogens, and present antigens to T cells.

Question 17

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

Accepted Answer

It has both immunogenicity and reactivity.

Question 18

A patient develops an autoimmune disease in which their immune system attacks their own tissues. Which of the following best explains the underlying mechanism?

Accepted Answer

Loss of self-tolerance, leading to immune responses against self-antigens.

Question 19

Which of the following best describes the function of antigenic determinants?

Accepted Answer

They are specific parts of an antigen that antibodies or lymphocyte receptors bind to.

Immune System Part 2: 1-29

Study Guide - Practice Questions

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