$$\text{Infection} \rightarrow \text{Disease (sometimes)}$$

Question 1

Which of the following best describes mutualism in a symbiotic relationship?

Accepted Answer

Both partners benefit from the interaction and cannot live without each other.

Question 2

Staphylococcus epidermidis growing on human skin is an example of which type of symbiotic relationship?

Accepted Answer

Commensalism

Question 3

Which of the following is NOT a way that normal microbiota can become opportunistic pathogens?

Accepted Answer

Increase in host body temperature

Question 4

Which of the following is an example of a zoonosis?

Accepted Answer

Tapeworm infection acquired from eating undercooked dog meat

Question 5

A person who carries a pathogen but never develops symptoms is known as a:

Accepted Answer

Carrier

Question 6

Which of the following statements about infection and disease is correct?

Accepted Answer

Infection is the invasion of a pathogen, which may or may not result in disease.

Question 7

According to Koch's postulates, which step is necessary to establish causation of a disease?

Accepted Answer

The suspected pathogen must be isolated and grown in pure culture.

Question 8

Which of the following is a virulence factor that enables pathogens to evade host defenses?

Accepted Answer

Antiphagocytic factors

Question 9

If a bacterium loses its ability to produce adhesins, what is the most likely outcome?

Accepted Answer

It will be unable to attach to host cells and may become avirulent.

Question 10

Which extracellular enzyme is responsible for digesting hyaluronic acid, the 'glue' that holds animal cells together?

Accepted Answer

Hyaluronidase

Question 11

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

Accepted Answer

Resident microbiota becoming opportunistic pathogens

Question 12

Which of the following best explains why animal reservoirs are a continual source of new human infections?

Accepted Answer

Animal reservoirs have a large number of animals located somewhere, making it hard to stop infection.

Question 13

Which of the following is a correct application of Koch's postulates in modern microbiology?

Accepted Answer

Some diseases are caused by a combination of pathogens and environmental effects.

Question 14

Which of the following is a sign of disease?

Accepted Answer

Vomiting

Question 15

Which formula best represents the relationship between infection and disease?

Accepted Answer

$$	ext{Infection} ightarrow 	ext{Disease (sometimes)}$$

Question 16

Which of the following is NOT a function of extracellular enzymes produced by pathogens?

Accepted Answer

Producing antibodies against the host

Question 17

Which of the following is an example of a pathogen using a specific adhesion factor to infect a host?

Accepted Answer

Neisseria gonorrhea using fimbriae to attach to cells lining the urethra and vagina

Question 18

Which of the following best describes the role of biofilm formation in pathogenicity?

Accepted Answer

Biofilms allow pathogens to evade host defenses and persist in the body.

Question 19

Which of the following is a plausible outcome when a contaminating microbe is exposed to resident microbiota?

Accepted Answer

The contaminating microbe may disappear as resident microbiota outcompete it.

Question 20

Which of the following is a correct statement about virulence?

Accepted Answer

Virulence is the degree of pathogenicity.

Microbial Interactions, Pathogenicity, and Infectious Disease: Study Notes

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