Question 1

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

Accepted Answer

Innate immunity is noninducible and does not require previous exposure, while adaptive immunity is acquired and depends on previous exposure to a specific pathogen.

Question 2

Which of the following is NOT a physical or chemical barrier to pathogen invasion?

Accepted Answer

Production of antibodies by plasma cells

Question 3

A patient receives an injection of pre-formed antibodies after exposure to a toxin. Which type of immunity is this?

Accepted Answer

Artificial passive immunity

Question 4

Which of the following best explains why Mycobacterium tuberculosis can survive inside phagocytes?

Accepted Answer

It has a waxy cell wall and produces carotenoids to neutralize singlet oxygen.

Question 5

Which of the following statements about fever is CORRECT?

Accepted Answer

Fever is caused by cytokines called pyrogens, which increase body temperature and can inhibit the growth of some pathogens.

Question 6

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

Accepted Answer

Severe Combined Immune Deficiency (SCID)

Question 7

Which of the following is a function of transferrins during a fever?

Accepted Answer

They sequester iron, limiting its availability to pathogens.

Question 8

Which of the following best describes the role of pattern recognition receptors (PRRs) in innate immunity?

Accepted Answer

They are membrane-bound or soluble proteins on leukocytes that recognize pathogen-associated molecular patterns (PAMPs).

Question 9

Which of the following is an example of natural passive immunity?

Accepted Answer

Passing antibodies to a nursing infant through breast milk

Question 10

A patient develops an inappropriate immune response that results in tissue damage after exposure to pollen. This is best described as:

Accepted Answer

Allergy (antibody-mediated immediate hypersensitivity)

Question 11

Which of the following best explains why vaccines are effective against encapsulated bacteria like Streptococcus pneumoniae?

Accepted Answer

Vaccines stimulate the production of host antibodies that can bind to the capsule, making it easier for phagocytes to engulf the bacteria.

Question 12

Which of the following is a key feature of adaptive immunity that distinguishes it from innate immunity?

Accepted Answer

It is directed toward individual molecular components (antigens) and has memory for faster, stronger responses upon re-exposure.

Question 13

Which of the following best describes the process of extravasation during inflammation?

Accepted Answer

The movement of neutrophils and macrophages from the bloodstream into tissues at the site of infection.

Question 14

Which of the following is TRUE regarding the specificity of the adaptive immune response?

Accepted Answer

It is determined by the interaction of lymphocyte cell receptors with individual antigens.

Question 15

A patient with HIV develops multiple opportunistic infections and certain cancers. This is primarily due to:

Accepted Answer

Deficiency in CD4+ T cell help

Question 16

Which of the following best explains why systemic inflammation can lead to septic shock?

Accepted Answer

Systemic inflammation increases vascular permeability, leading to decreased blood pressure and potential multi-organ damage.

Question 17

Which of the following is the best example of an antigenic determinant (epitope)?

Accepted Answer

A specific sequence of amino acids on a viral protein recognized by an antibody

Question 18

Which of the following is a consequence of a deficiency in B cells?

Accepted Answer

Increased susceptibility to bacterial infections

Question 19

Which of the following best describes the role of memory cells in adaptive immunity?

Accepted Answer

They provide a faster and stronger immune response upon re-exposure to the same antigen.

Question 20

Which of the following is a characteristic of passive immunity?

Accepted Answer

It provides immediate, but short-lived, protection by transferring pre-formed antibodies or cells.

Introduction to Immunology: Innate and Adaptive Host Defenses

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