Question 1

Which of the following best describes the relationship in commensalism, a type of symbiosis?

Accepted Answer

One organism benefits while the other is neither helped nor harmed.

Question 2

A hospitalized patient develops a urinary tract infection after catheterization. This infection is best classified as:

Accepted Answer

A nosocomial infection

Question 3

Which of the following is NOT a typical mode of transmission for infectious diseases?

Accepted Answer

Genetic transmission

Question 4

Which of the following conditions is most likely to cause normal microbiota to become opportunistic pathogens?

Accepted Answer

Antibiotic therapy disrupting normal flora

Question 5

Which of the following blood cells is capable of both diapedesis and phagocytosis?

Accepted Answer

Neutrophils

Question 6

During the process of phagocytosis, which stage immediately follows the ingestion of the microbe?

Accepted Answer

Formation of the phagolysosome

Question 7

Which of the following statements about innate immunity is correct?

Accepted Answer

It is present from birth and responds rapidly to infections.

Question 8

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

Accepted Answer

Inducing antiviral states in neighboring cells

Question 9

Which of the following best explains why adaptive immunity is also called 'acquired' immunity?

Accepted Answer

It develops after exposure to specific antigens.

Question 10

Which of the following molecules is most likely to be a strong antigen?

Accepted Answer

A large, complex protein

Question 11

In order for an antigen to trigger an adaptive immune response, its epitope must be presented on which host cell structure?

Accepted Answer

Major Histocompatibility Complex (MHC)

Question 12

Which type of adaptive immunity is primarily directed at intracellular pathogens such as viruses?

Accepted Answer

Cell-mediated immunity

Question 13

Which of the following best describes the process of clonal deletion?

Accepted Answer

The elimination of self-reactive lymphocytes during development

Question 14

Which of the following is a key difference between active and passive immunity?

Accepted Answer

Active immunity involves the host's own immune response, while passive immunity involves transfer of antibodies.

Question 15

A patient receives an injection of antiserum after exposure to a toxin. This is an example of which type of acquired immunity?

Accepted Answer

Artificially acquired passive immunity

Question 16

Which of the following best describes herd immunity?

Accepted Answer

Protection of unvaccinated individuals due to a high percentage of immune individuals in the population

Question 17

What is the minimum percentage of immune individuals in a population generally required to achieve herd immunity for most diseases?

Accepted Answer

$$95\%$$

Question 18

Which of the following is a key measure of vaccine success?

Accepted Answer

The reduction in disease incidence in the population

Question 19

When a specific antibody encounters its corresponding antigen in a serological test, what is the expected outcome?

Accepted Answer

The antibody and antigen will bind to form an immune complex.

Question 20

A live attenuated vaccine is characterized by which of the following?

Accepted Answer

It contains weakened pathogens that can replicate but do not cause disease in healthy individuals.

Microbiology Exam Review: Infection, Immunity, and Immunization (Chapters 14–17)

Study Guide - Practice Questions