Question 1

Which of the following best describes the role of the membrane attack complex (MAC) in the complement system?

Accepted Answer

It forms a pore in the microbial membrane, causing cytolysis by allowing water and electrolytes to flow in and out.

Question 2

A patient receives an injection of antibodies after a snakebite. Which type of immunity is this an example of?

Accepted Answer

Artificial passive immunity

Question 3

Which antibody class is most abundant in the secondary immune response and can cross the placenta to provide immunity to the fetus?

Accepted Answer

IgG

Question 4

What is the primary function of C3b in the complement system?

Accepted Answer

To coat microbial cells and enhance phagocytosis (opsonization)

Question 5

Which process allows the immune system to generate a vast diversity of antibodies from a limited number of genes?

Accepted Answer

Somatic recombination and somatic hypermutation

Question 6

A newborn receives antibodies from its mother through breast milk. This is an example of:

Accepted Answer

Natural passive immunity

Question 7

Which of the following is a distinguishing characteristic of adaptive immunity compared to innate immunity?

Accepted Answer

It has specificity and memory for particular pathogens.

Question 8

Which antibody class is primarily responsible for agglutination and complement fixation during the primary immune response?

Accepted Answer

IgM

Question 9

What is the outcome when natural killer (NK) cells release perforins and granzymes onto a target cell?

Accepted Answer

The target cell undergoes apoptosis.

Question 10

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

Accepted Answer

It is initiated when antibodies bind to a microbe, exposing complement-binding sites.

Question 11

Which region of the antibody determines its class and mechanism of action?

Accepted Answer

Constant (C) region

Question 12

A patient with a genetic defect cannot produce C3 protein. Which immune process would be most directly impaired?

Accepted Answer

Phagocytosis via opsonization

Question 13

Which of the following is true regarding haptens?

Accepted Answer

They must bind to a host molecule to become antigenic.

Question 14

Which cell type is responsible for directly attacking and destroying infected or cancerous host cells in cellular immunity?

Accepted Answer

T lymphocytes

Question 15

Which of the following best describes the process of negative selection in T cell development?

Accepted Answer

T cells that react to self-antigen are eliminated to ensure self-tolerance.

Question 16

Which complement activation pathway is triggered by plasma proteins binding to specific sugars on the microbial surface?

Accepted Answer

Lectin pathway

Question 17

Which of the following is a function of IgA antibodies?

Accepted Answer

Preventing pathogen adherence to epithelial surfaces

Question 18

Which of the following best explains why booster shots are sometimes necessary after vaccination?

Accepted Answer

To restimulate immune memory and maintain high antibody levels

Question 19

Which of the following is NOT a typical outcome of complement activation?

Accepted Answer

Direct production of antibodies

Question 20

A patient is exposed to a pathogen and develops their own antibodies and T cells as a result. This is an example of:

Accepted Answer

Natural active immunity

Antimicrobial Proteins and Adaptive Immunity: Complement System, NK Cells, and Antibodies

Study Guide - Practice Questions