Question 1

Which of the following best describes the role of Toll-like receptors (TLRs) in the innate immune response?

Accepted Answer

They recognize pathogen-associated molecular patterns (PAMPs) and initiate signaling cascades that activate immune responses.

Question 2

A patient presents with a bacterial infection. Which of the following leukocytes is most likely to arrive first at the site of infection and begin phagocytosis?

Accepted Answer

Neutrophils

Question 3

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

Accepted Answer

Directly neutralizing viral RNA inside host cells

Question 4

Which chemical mediator is primarily responsible for increasing vascular permeability during inflammation?

Accepted Answer

Histamine

Question 5

A researcher is studying the effect of interferon alpha ($$\alpha) $$and interferon beta ($$\beta) on $$viral infections. What is the primary mechanism by which these interferons limit viral spread?

Accepted Answer

They induce the production of antiviral proteins in neighboring cells, inhibiting viral replication.

Question 6

Which of the following best explains why the skin is an effective barrier against microbial invasion?

Accepted Answer

It is composed of multiple layers of tightly packed cells and contains antimicrobial substances such as sebum and dermcidins.

Question 7

During the inflammatory response, which sequence of events occurs first?

Accepted Answer

Release of chemical mediators such as histamine and bradykinin

Question 8

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

Accepted Answer

Increased susceptibility to bacterial infections due to impaired opsonization and membrane attack complex formation

Question 9

Which of the following best describes the process of diapedesis?

Accepted Answer

The movement of leukocytes out of blood vessels and into surrounding tissues

Question 10

Which of the following is a hallmark sign of inflammation?

Accepted Answer

Edema (swelling)

Question 11

A patient develops a fever after a bacterial infection. Which of the following best explains the physiological mechanism leading to fever?

Accepted Answer

Pyrogens reset the hypothalamic set point, causing the body to increase its temperature.

Question 12

Which of the following best describes the role of opsonins in the immune response?

Accepted Answer

They coat pathogens to enhance their recognition and ingestion by phagocytes.

Question 13

Which of the following is a correct match between a leukocyte and its primary function?

Accepted Answer

Eosinophils – defense against parasitic worms

Question 14

A laboratory experiment shows that a certain bacterial strain is resistant to lysozyme. Which of the following is the most likely explanation for this resistance?

Accepted Answer

The bacterium has an altered peptidoglycan structure that prevents lysozyme from hydrolyzing its cell wall.

Question 15

Which of the following best describes the alternative pathway of complement activation?

Accepted Answer

It is triggered by the spontaneous hydrolysis of complement protein C3 and does not require antibodies.

Question 16

A patient with a severe burn loses much of their epidermis. Which of the following consequences is most likely?

Accepted Answer

Increased risk of infection due to loss of a physical and chemical barrier

Question 17

Which of the following best explains the concept of microbial antagonism?

Accepted Answer

Normal microbiota compete with potential pathogens, limiting their ability to colonize the host.

Question 18

Which of the following is a correct sequence of events in phagocytosis?

Accepted Answer

Chemotaxis → Adherence → Ingestion → Digestion → Exocytosis

Question 19

A patient is exposed to a virus. Which of the following best describes how interferon alpha and beta protect neighboring cells?

Accepted Answer

They induce the expression of genes encoding antiviral proteins that inhibit viral replication.

Question 20

Which of the following best describes the function of bradykinin during inflammation?

Accepted Answer

It increases vascular permeability and stimulates pain receptors.

Innate Immunity: Nonspecific Lines of Defense (Chapter 15 Study Guide)

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