Question 1

Which of the following best describes mutualism in the context of symbiotic relationships between microbes and their hosts?

Accepted Answer

Both organisms benefit from the relationship.

Question 2

A patient develops a yeast infection after taking broad-spectrum antibiotics. This is an example of which phenomenon?

Accepted Answer

Opportunistic infection due to changes in normal microbiota

Question 3

Which of the following is NOT a typical portal of entry for pathogens?

Accepted Answer

Liver

Question 4

Which of the following statements about resident microbiota is TRUE?

Accepted Answer

They are a part of the normal microbiota throughout life and are mostly commensal.

Question 5

A disease that is naturally spread from animal hosts to humans is called:

Accepted Answer

Zoonosis

Question 6

Which of the following is a reason why transient microbiota cannot persist in the body?

Accepted Answer

They are eliminated by the body’s defense cells.

Question 7

Which of the following is an example of a nonliving reservoir of infection?

Accepted Answer

Contaminated soil

Question 8

A microbe enters the body through a cut in the skin caused by a contaminated needle. This is an example of which route of entry?

Accepted Answer

Parenteral route

Question 9

Which of the following best explains why the respiratory tract is the most common site of entry for pathogens?

Accepted Answer

It provides a moist, warm environment that is hospitable to pathogens.

Question 10

Which of the following scenarios would most likely result in an opportunistic infection?

Accepted Answer

A patient with immune suppression due to chemotherapy

Question 11

Which of the following is a critical step in the establishment of infection by a pathogen?

Accepted Answer

The pathogen must adhere to host cells using adhesion factors.

Question 12

Which of the following best describes the role of ligands (adhesion factors) in microbial infection?

Accepted Answer

They bind to specific receptors on host cells, determining host cell specificity.

Question 13

A pregnant woman contracts an infection that crosses the placenta and causes birth defects. Which portal of entry did the pathogen use?

Accepted Answer

Placenta

Question 14

Which of the following is a plausible reason why humans are often dead-end hosts for zoonotic pathogens?

Accepted Answer

Humans cannot transmit the pathogen back to animals or other humans efficiently.

Question 15

Which of the following is an example of commensalism?

Accepted Answer

Staphylococcus epidermidis living on human skin without causing harm or benefit

Question 16

Which of the following best describes the difference between contamination and infection?

Accepted Answer

Contamination refers to the presence of microbes, while infection means the microbes have evaded defenses, multiplied, and become established.

Question 17

Which of the following is a plausible multi-step scenario for the development of an infectious disease?

Accepted Answer

A person eats contaminated food, the pathogen survives stomach acid, adheres to intestinal cells, and multiplies to cause disease.

Question 18

Which of the following would most likely render a microorganism avirulent?

Accepted Answer

Inability to make attachment proteins or adhesins

Question 19

Which of the following is a real-world example of a nonliving reservoir leading to human infection?

Accepted Answer

A person contracts tetanus from a puncture wound contaminated with soil.

Question 20

Which of the following best explains why changing or blocking a ligand or its receptor can prevent infection?

Accepted Answer

It prevents the microbe from adhering to host cells, thus blocking colonization.

Infection, Infectious Diseases, and Epidemiology: Microbial Interactions and Host Invasion

Study Guide - Practice Questions