Question 1

Which of the following best describes the relationship between susceptibility (S) and resistance (R) in the host-parasite interaction?

Accepted Answer

Disease develops when susceptibility (S) outweighs resistance (R).

Question 2

A newborn baby acquires its normal microbiota primarily through which of the following processes?

Accepted Answer

Exposure to microorganisms during passage through the birth canal and contact with the environment.

Question 3

Which of the following is an example of mutualism in human-microbe interactions?

Accepted Answer

Escherichia coli in the colon synthesizing vitamin K for the host.

Question 4

Normal microbiota can become opportunistic pathogens under which of the following circumstances?

Accepted Answer

When they are introduced into an unusual site in the body.

Question 5

Which of the following is NOT a type of reservoir of infection?

Accepted Answer

Fomites

Question 6

A patient contracts rabies after being bitten by a dog. Which of the following best describes this scenario?

Accepted Answer

The disease is a zoonosis transmitted by direct contact.

Question 7

Which of the following statements about portals of entry is correct?

Accepted Answer

The parenteral route involves direct deposition of pathogens into tissues beneath the skin or mucous membranes.

Question 8

Which of the following pathogens can cross the placenta and what type of microorganism is it?

Accepted Answer

Treponema pallidum, a bacterium

Question 9

Adhesion is a critical step in the establishment of infection. Which of the following structures is commonly used by bacteria for adhesion?

Accepted Answer

Fimbriae

Question 10

Which of the following best differentiates infection from disease?

Accepted Answer

Infection is the invasion and multiplication of pathogens in the host, while disease is the result of tissue damage and impaired function.

Question 11

Which of the following is an example of a sign of disease?

Accepted Answer

Fever of $$39^\circC$$

Question 12

According to Koch’s postulates, which of the following must be true to establish a microorganism as the cause of a disease?

Accepted Answer

The microorganism must be isolated from a diseased host and grown in pure culture.

Question 13

Which of the following enzymes produced by bacteria allows them to break down connective tissue and spread through the host?

Accepted Answer

Collagenase

Question 14

Which of the following statements about exotoxins and endotoxins is correct?

Accepted Answer

Exotoxins are proteins, while endotoxins are lipopolysaccharides.

Question 15

A bacterial capsule contributes to virulence primarily by:

Accepted Answer

Preventing phagocytosis by host immune cells.

Question 16

Which of the following best describes the action of leukocidins?

Accepted Answer

They destroy white blood cells, impairing the host's immune response.

Question 17

Arrange the stages of infectious disease in the correct order:

Accepted Answer

Incubation period, prodromal period, illness, convalescence

Question 18

Which of the following is an example of vehicle transmission of disease?

Accepted Answer

A person contracts hepatitis A from contaminated water.

Question 19

Which of the following best describes a chronic disease?

Accepted Answer

A disease that develops slowly and persists over a long period.

Question 20

Why is prevalence always greater than incidence for a given disease?

Accepted Answer

Prevalence is the total number of cases (new and existing), while incidence is only new cases.

Microbiology: Infection and Diseases – Guided Study Notes

Study Guide - Practice Questions