Question 1

Which of the following best describes the primary function of innate immunity?

Accepted Answer

To rapidly respond to pathogens in a non-specific manner without memory.

Question 2

Which structure acts as the first line of defense by providing a physical barrier against microbial invasion?

Accepted Answer

Epidermis

Question 3

What is the role of goblet cells in mucous membranes?

Accepted Answer

Secrete mucus to trap microbes and particles.

Question 4

Which chemical found in tears, saliva, and sweat breaks down peptidoglycan in bacterial cell walls?

Accepted Answer

Lysozyme

Question 5

Competitive exclusion by normal microbiota helps protect the host by:

Accepted Answer

Competing for binding sites and nutrients, preventing pathogen colonization.

Question 6

Which blood cell is primarily responsible for phagocytosis and can leave the bloodstream to enter tissues?

Accepted Answer

Neutrophil

Question 7

During inflammation, which chemical is released by basophils and mast cells to increase blood vessel permeability?

Accepted Answer

Histamine

Question 8

Which process describes the movement of phagocytes from blood vessels into tissues?

Accepted Answer

Diapedesis

Question 9

A pathogen with a capsule can evade phagocytosis by:

Accepted Answer

Inhibiting adherence to phagocytes.

Question 10

Which of the following is NOT a result of complement activation?

Accepted Answer

Production of antibodies

Question 11

In the classical pathway of complement activation, what triggers the cascade?

Accepted Answer

Antigen-antibody complexes binding to C1

Question 12

Which equation best represents the splitting of C3 in complement activation?

Accepted Answer

$$C3 \rightarrow C3a + C3b$$

Question 13

Which cells are responsible for cell-mediated immunity and directly engage with pathogens?

Accepted Answer

T cells

Question 14

A patient with a chronic inflammatory response is likely to experience:

Accepted Answer

Significant tissue damage and formation of scar tissue.

Question 15

Which antimicrobial substance binds iron and competes with microbial siderophores?

Accepted Answer

Transferrin

Question 16

Which process is enhanced by the binding of C3b to the surface of a microbe?

Accepted Answer

Opsonization

Question 17

Which of the following is a function of interferons released by virus-infected cells?

Accepted Answer

Induce neighboring cells to produce antiviral proteins (AVPs) that inhibit viral replication.

Question 18

Which equation best represents the formation of the membrane attack complex (MAC) in complement activation?

Accepted Answer

$$C5b + C6 + C7 + C8 + C9 \rightarrow MAC$$

Question 19

Which of the following is a plausible consequence of a Gram-negative bacterium altering its LPS surface?

Accepted Answer

Prevention of membrane attack complex (MAC) formation and increased resistance to complement-mediated lysis.

Question 20

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

Accepted Answer

Reduced opsonization, inflammation, and cytolysis, leading to increased susceptibility to infections.

Innate Immunity: The Body’s First and Second Lines of Defense

Study Guide - Practice Questions