Question 1

Which of the following best describes the role of the skin as a physical factor in innate immunity?

Accepted Answer

It acts as a barrier due to tightly packed cells and the presence of keratin, a protective protein.

Question 2

Which chemical factor found in sebum contributes to the skin's antimicrobial properties?

Accepted Answer

Acidic fatty acids

Question 3

A patient has a fever of 40°C. Which of the following is a physiological advantage of fever in fighting infection?

Accepted Answer

It inhibits the growth of some pathogens and increases interferon production.

Question 4

Which process is described by the ingestion of microbes or particles by a cell, performed by neutrophils and macrophages?

Accepted Answer

Phagocytosis

Question 5

Which of the following is NOT a function of the complement system?

Accepted Answer

Antibody production

Question 6

A laboratory test shows a patient has a low percentage of neutrophils in their differential white cell count. What is the most likely consequence?

Accepted Answer

Decreased ability to ingest and destroy bacteria

Question 7

Which equation correctly represents the O2-dependent killing mechanism in phagocytes?

Accepted Answer

$$O_2$$ \rightarrow $$O_2$$^- \rightarrow H_2O_2$$

Question 8

Which of the following best explains competitive exclusion by the normal microbiome?

Accepted Answer

Normal microbiome competes with pathogens for nutrients and attachment sites.

Question 9

Which of the following is a chemical released by damaged cells that increases permeability of blood vessels and attracts phagocytes?

Accepted Answer

Histamine

Question 10

A bacterial pathogen avoids complement-mediated lysis by preventing formation of the membrane attack complex (MAC). Which bacterial structure is most likely responsible?

Accepted Answer

Capsule

Question 11

Which of the following is TRUE regarding interferons?

Accepted Answer

IFN-alpha and IFN-beta cause cells to produce antiviral proteins that inhibit viral replication.

Question 12

Which of the following is a function of transferrins in innate immunity?

Accepted Answer

Bind serum iron to limit bacterial growth

Question 13

A patient with a genetic deficiency in complement protein C3 would most likely experience which of the following?

Accepted Answer

Decreased phagocytosis and increased susceptibility to bacterial infections

Question 14

Which of the following is a correct sequence of events in the complement activation cascade?

Accepted Answer

$$C3 \rightarrow C3a + C3b$$

Question 15

Which of the following is a disadvantage of fever?

Accepted Answer

Tachycardia and acidosis

Question 16

Which of the following best describes the role of acute-phase proteins in inflammation?

Accepted Answer

They are activated by cytokines and help mediate the inflammatory response.

Question 17

Which of the following is a physical factor that helps prevent microbial invasion?

Accepted Answer

Mucus trapping microbes in the respiratory tract

Question 18

Which of the following is a function of antimicrobial peptides in innate immunity?

Accepted Answer

Lyse bacterial cells

Question 19

A patient is exposed to a pathogen but does not develop disease due to the action of their adaptive immunity. Which term best describes this?

Accepted Answer

Immunity

Question 20

Which of the following is a chemical factor that inhibits microbial growth in the stomach?

Accepted Answer

Low pH (1.2-3.0) of gastric juice

Innate Immunity and Host Defenses: Microbiology Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard