CHAMBERLAIN UNIVERSITY
3 MAXE
CU
EST. 1889 College of Nursing & Health Professions
BIOS 242: Fundamentals of Microbiology
EXAMINATION III — IMMUNITY, INFECTIOUS DISEASES BY BODY SYSTEM & PATHOGEN
CHARACTERISTICS
INSTITUTION PROGRAM
Chamberlain University Bachelor of Science in Nursing (BSN)
COURSE CODE COURSE TITLE
BIOS 242 Fundamentals of Microbiology
ACADEMIC YEAR EXAM TITLE
2025–2026 Examination III — Immunity & Infectious Diseases
TOTAL QUESTIONS EXAM FORMAT
65 Multiple Choice — Select the Single Best Answer
General Instructions
▸ Read each question carefully before selecting your answer.
▸ Select the single best answer for each multiple-choice item.
▸ This examination covers the immune system (innate and adaptive defenses), infectious diseases organized by
body system, pathogen characteristics, and immunity types.
▸ All questions are weighted equally unless otherwise noted.
▸ Electronic devices, notes, and reference materials are prohibited during the examination.
Q MULTIPLE CHOICE QUESTIONS 65 Questions
,1. The immune system's first line of defense includes all of the following EXCEPT:
A. Skin and mucous membranes
B. Lysozyme and sebum
C. Natural killer cells
D. Normal microbiota
CORRECT ANSWER:
C. Natural killer cells
RATIONALE:
Natural killer cells are part of the second line of defense (nonspecific, internal cellular defenses). The first line of
defense consists of nonspecific, external barriers: physical barriers (skin, mucous membranes, mechanical
removal), chemical barriers (lysozyme, sebum, acidic environments), and microbiota that outcompete
pathogens.
2. How does lysozyme function as a chemical barrier?
A. It creates an acidic environment on the skin
B. It breaks down peptidoglycan in bacterial cell walls
C. It produces oily secretions that inhibit microbes
D. It traps microbes in mucus
CORRECT ANSWER:
B. It breaks down peptidoglycan in bacterial cell walls
RATIONALE:
Lysozyme, found in tears, saliva, and sweat, is an enzyme that hydrolyzes peptidoglycan — the structural
polymer unique to bacterial cell walls. Option C describes sebum. Option A describes the acidic pH of skin.
Option D describes mucous membrane function.
,3. The complement system's Membrane Attack Complex (MAC) functions by:
A. Blocking viral replication inside host cells
B. Forming pores in microbial membranes resulting in lysis
C. Neutralizing bacterial toxins
D. Activating B cells to produce antibodies
CORRECT ANSWER:
B. Forming pores in microbial membranes resulting in lysis
RATIONALE:
The MAC is the end product of all three complement pathways (classical, alternative, and lectin). It assembles
into a pore that inserts into the microbial cell membrane, causing osmotic lysis. Option A describes interferons.
Option C describes antitoxins. Option D describes helper T cell function.
4. Interferons are produced by virus-infected cells and function to:
A. Directly kill virus-infected cells
B. Warn neighboring cells to produce antiviral proteins
C. Opsonize bacteria for phagocytosis
D. Activate the complement cascade
CORRECT ANSWER:
B. Warn neighboring cells to produce antiviral proteins
RATIONALE:
Interferons are cytokines released by virus-infected cells that act as a warning system — they bind to
neighboring uninfected cells, inducing them to produce antiviral proteins that inhibit viral replication. The
infected cell sacrifices itself. Option A describes cytotoxic T cells. Option D describes the classical complement
pathway.
, 5. Cytotoxic T cells (CD8) kill infected cells by:
A. Producing antibodies
B. Releasing perforin and granzyme to induce apoptosis
C. Engulfing pathogens through phagocytosis
D. Activating the complement system
CORRECT ANSWER:
B. Releasing perforin and granzyme to induce apoptosis
RATIONALE:
Cytotoxic T cells (CD8+) recognize MHC Class I antigens on infected cells and release perforin (creates pores) and
granzyme (induces apoptosis). They directly kill target cells. Option A describes B cell/plasma cell function.
Option C describes phagocyte function. Helper T cells (CD4+) activate other immune cells.
6. Helper T cells (CD4) function by:
A. Directly killing virus-infected cells
B. Secreting cytokines that activate B cells and cytotoxic T cells
C. Producing antibodies
D. Phagocytizing extracellular pathogens
CORRECT ANSWER:
B. Secreting cytokines that activate B cells and cytotoxic T cells
RATIONALE:
Helper T cells (CD4+) are the "orchestrators" of adaptive immunity. They recognize MHC Class II antigens on
antigen-presenting cells and secrete cytokines that activate B cells (humoral immunity) and cytotoxic T cells
(cell-mediated immunity). HIV targets these cells, crippling both arms of adaptive immunity.
3 MAXE
CU
EST. 1889 College of Nursing & Health Professions
BIOS 242: Fundamentals of Microbiology
EXAMINATION III — IMMUNITY, INFECTIOUS DISEASES BY BODY SYSTEM & PATHOGEN
CHARACTERISTICS
INSTITUTION PROGRAM
Chamberlain University Bachelor of Science in Nursing (BSN)
COURSE CODE COURSE TITLE
BIOS 242 Fundamentals of Microbiology
ACADEMIC YEAR EXAM TITLE
2025–2026 Examination III — Immunity & Infectious Diseases
TOTAL QUESTIONS EXAM FORMAT
65 Multiple Choice — Select the Single Best Answer
General Instructions
▸ Read each question carefully before selecting your answer.
▸ Select the single best answer for each multiple-choice item.
▸ This examination covers the immune system (innate and adaptive defenses), infectious diseases organized by
body system, pathogen characteristics, and immunity types.
▸ All questions are weighted equally unless otherwise noted.
▸ Electronic devices, notes, and reference materials are prohibited during the examination.
Q MULTIPLE CHOICE QUESTIONS 65 Questions
,1. The immune system's first line of defense includes all of the following EXCEPT:
A. Skin and mucous membranes
B. Lysozyme and sebum
C. Natural killer cells
D. Normal microbiota
CORRECT ANSWER:
C. Natural killer cells
RATIONALE:
Natural killer cells are part of the second line of defense (nonspecific, internal cellular defenses). The first line of
defense consists of nonspecific, external barriers: physical barriers (skin, mucous membranes, mechanical
removal), chemical barriers (lysozyme, sebum, acidic environments), and microbiota that outcompete
pathogens.
2. How does lysozyme function as a chemical barrier?
A. It creates an acidic environment on the skin
B. It breaks down peptidoglycan in bacterial cell walls
C. It produces oily secretions that inhibit microbes
D. It traps microbes in mucus
CORRECT ANSWER:
B. It breaks down peptidoglycan in bacterial cell walls
RATIONALE:
Lysozyme, found in tears, saliva, and sweat, is an enzyme that hydrolyzes peptidoglycan — the structural
polymer unique to bacterial cell walls. Option C describes sebum. Option A describes the acidic pH of skin.
Option D describes mucous membrane function.
,3. The complement system's Membrane Attack Complex (MAC) functions by:
A. Blocking viral replication inside host cells
B. Forming pores in microbial membranes resulting in lysis
C. Neutralizing bacterial toxins
D. Activating B cells to produce antibodies
CORRECT ANSWER:
B. Forming pores in microbial membranes resulting in lysis
RATIONALE:
The MAC is the end product of all three complement pathways (classical, alternative, and lectin). It assembles
into a pore that inserts into the microbial cell membrane, causing osmotic lysis. Option A describes interferons.
Option C describes antitoxins. Option D describes helper T cell function.
4. Interferons are produced by virus-infected cells and function to:
A. Directly kill virus-infected cells
B. Warn neighboring cells to produce antiviral proteins
C. Opsonize bacteria for phagocytosis
D. Activate the complement cascade
CORRECT ANSWER:
B. Warn neighboring cells to produce antiviral proteins
RATIONALE:
Interferons are cytokines released by virus-infected cells that act as a warning system — they bind to
neighboring uninfected cells, inducing them to produce antiviral proteins that inhibit viral replication. The
infected cell sacrifices itself. Option A describes cytotoxic T cells. Option D describes the classical complement
pathway.
, 5. Cytotoxic T cells (CD8) kill infected cells by:
A. Producing antibodies
B. Releasing perforin and granzyme to induce apoptosis
C. Engulfing pathogens through phagocytosis
D. Activating the complement system
CORRECT ANSWER:
B. Releasing perforin and granzyme to induce apoptosis
RATIONALE:
Cytotoxic T cells (CD8+) recognize MHC Class I antigens on infected cells and release perforin (creates pores) and
granzyme (induces apoptosis). They directly kill target cells. Option A describes B cell/plasma cell function.
Option C describes phagocyte function. Helper T cells (CD4+) activate other immune cells.
6. Helper T cells (CD4) function by:
A. Directly killing virus-infected cells
B. Secreting cytokines that activate B cells and cytotoxic T cells
C. Producing antibodies
D. Phagocytizing extracellular pathogens
CORRECT ANSWER:
B. Secreting cytokines that activate B cells and cytotoxic T cells
RATIONALE:
Helper T cells (CD4+) are the "orchestrators" of adaptive immunity. They recognize MHC Class II antigens on
antigen-presenting cells and secrete cytokines that activate B cells (humoral immunity) and cytotoxic T cells
(cell-mediated immunity). HIV targets these cells, crippling both arms of adaptive immunity.
