Question 1

Which of the following best describes the human microbiome?

Accepted Answer

The sum total of all microbes found in a normal human.

Question 2

Which group of microorganisms is the most numerous in the human microbiome?

Accepted Answer

Bacteria

Question 3

What is the primary role of resident microbiota (normal biota) in humans?

Accepted Answer

To colonize the host for a long term without causing disease

Question 4

Which of the following is a condition in which microbes overcome host defenses, enter tissues, and multiply?

Accepted Answer

Infection

Question 5

What is the term for the cumulative effects of infection that disrupt tissues and organs?

Accepted Answer

Disease

Question 6

Which of the following is NOT a factor that increases susceptibility to infection?

Accepted Answer

Regular exercise

Question 7

What is the definition of virulence?

Accepted Answer

The degree of pathogenicity of a microorganism

Question 8

Which of the following is an example of an opportunistic pathogen?

Accepted Answer

Pseudomonas species

Question 9

What is the infectious dose (ID)?

Accepted Answer

The quantity of microbes in the inoculating dose required to cause infection

Question 10

Which portal of entry is most commonly used by pathogens?

Accepted Answer

Mucous membranes

Question 11

A patient develops a rapid onset of disease after exposure to a high quantity of Salmonella. Which concept explains this phenomenon?

Accepted Answer

Infectious dose (ID)

Question 12

Which of the following is a virulence factor that helps bacteria avoid phagocytosis?

Accepted Answer

Capsule

Question 13

Which enzyme produced by pathogenic staphylococci causes clotting of plasma?

Accepted Answer

Coagulase

Question 14

Which of the following statements about exotoxins is TRUE?

Accepted Answer

They are secreted by bacteria and can damage host tissues.

Question 15

What is the effect of endotoxins, such as lipopolysaccharide (LPS), on host tissues?

Accepted Answer

They can cause severe inflammation, hemorrhage, and tissue damage.

Question 16

Which of the following is a multi-step process required for a microbe to cause infection?

Accepted Answer

Attachment to host tissue, evasion of host defenses, and production of toxins

Question 17

A patient with a compromised immune system is more likely to develop disease from which type of pathogen?

Accepted Answer

Opportunistic pathogen

Question 18

Which of the following is an example of microbial antagonism?

Accepted Answer

Resident microbiota outcompeting invading pathogens for attachment sites

Question 19

Which of the following is a characteristic of a true pathogen?

Accepted Answer

It can cause disease in healthy individuals with normal immune systems.

Question 20

Which of the following best describes Koch's postulates?

Accepted Answer

A set of rules for determining the cause of infectious conditions by isolating microbes in pure culture.

Interactions Between Microbes and Humans: The Human Microbiome, Infection, and Disease

Study Guide - Practice Questions