Question 1

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

Accepted Answer

Innate immunity is present at birth and responds rapidly, while adaptive immunity develops over time and is specific to particular antigens.

Question 2

Which cell type is primarily responsible for antibody production in the adaptive immune response?

Accepted Answer

B cells

Question 3

A patient is exposed to Leishmania donovani, a microorganism known to evade phagocytosis. Which mechanism does Leishmania donovani use to avoid destruction by macrophages?

Accepted Answer

It prevents fusion of the phagosome with the lysosome, avoiding degradation.

Question 4

Which of the following is a function of the complement system that directly leads to the destruction of pathogens?

Accepted Answer

Cytolysis

Question 5

A researcher is studying the classical and alternative pathways of complement activation. Which statement correctly distinguishes these two pathways?

Accepted Answer

The classical pathway is activated by antigen-antibody complexes, while the alternative pathway is activated by microbial surfaces.

Question 6

Which cytokine is most associated with the development of a 'cytokine storm' during severe infection?

Accepted Answer

Tumor necrosis factor-alpha (TNF-\alpha)

Question 7

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

Accepted Answer

PRRs recognize conserved microbial structures, promoting adherence and ingestion by phagocytes.

Question 8

Which lymphoid organ is the primary site for T cell maturation?

Accepted Answer

Thymus

Question 9

Which antibody class is most effective at neutralizing viruses in mucosal surfaces?

Accepted Answer

IgA

Question 10

A patient receives an injection of antivenom after a snake bite. Which type of immunity is this an example of?

Accepted Answer

Artificially acquired passive immunity

Question 11

Which of the following best describes the process of clonal selection in the humoral immune response?

Accepted Answer

B cells with receptors specific to an antigen proliferate and differentiate into plasma and memory cells.

Question 12

Which cell surface marker is characteristic of T helper cells?

Accepted Answer

CD4

Question 13

Trypanosoma brucei is able to evade the host antibody-mediated response by:

Accepted Answer

Frequently changing its surface glycoproteins, preventing recognition by antibodies.

Question 14

Which region of an antibody is responsible for binding to antigens?

Accepted Answer

Variable region

Question 15

Which of the following is a major function of antibodies that helps prevent viral infection?

Accepted Answer

Neutralization

Question 16

Which statement correctly describes the tissue distribution and antigen presentation of MHC I and MHC II molecules?

Accepted Answer

MHC I is found on all nucleated cells and presents endogenous antigens; MHC II is found on antigen-presenting cells and presents exogenous antigens.

Question 17

During a primary cell-mediated immune response (Th1), which cytokine is most important for activating cytotoxic T cells?

Accepted Answer

Interleukin-2 (IL-2)

Question 18

Which of the following best explains the importance of memory cells in the secondary immune response?

Accepted Answer

Memory cells allow for a faster and stronger response upon re-exposure to the same antigen.

Question 19

Influenza virus type A can evade the host immune response by:

Accepted Answer

Undergoing antigenic drift and shift, altering its surface proteins.

Question 20

A scientist is studying the effects of interferon production during viral infection. Which of the following best describes the role of interferons?

Accepted Answer

Interferons induce antiviral states in neighboring cells, inhibiting viral replication.

Study Guide: Host Defenses and Immunity (Chapters 15 & 16) – Microbiology

Study Guide - Practice Questions

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