EDIUG YDUTS • 242 SOIB
★ ★
Chamberlain University
C College of Nursing & Health Professions
J O U R N E Y T O E X T R A O R D I N A R Y CO M PA S S I O N AT E C A R E
EST. 1889
BIOS 242 — Exam 3 Comprehensive Study Guide
I M M U N E SYST E M · W B CS · A N T I B O D I E S · I N F E C T I O U S D I S E A S E S · H I V · SY P H I L I S · G I & S K I N I N F E C T I O N S
INSTITUTION Chamberlain University COURSE CODE BIOS 242
PROGRAM Bachelor of Science in Nursing (BSN) ACADEMIC YEAR
RESOURCE TYPE Comprehensive Study Guide / Practice Examination TOTAL QUESTIONS 25 Questions
COURSE TITLE Fundamentals of Microbiology FORMAT Multiple Choice — Select the Single Best Answer
STUDY GUIDE INSTRUCTIONS
▸ Select the single best answer for each question unless otherwise instructed.
▸ This study guide covers the three lines of immune defense, WBC functions, antibody classes, T/B cell roles, and major infectious diseases.
▸ All content reflects BIOS 242 learning objectives for Exam 3.
▸ Correct answers and detailed rationales appear below each question for comprehensive exam preparation.
▸ Pay careful attention to immune cell functions, immunoglobulin characteristics, and disease-specific causative agents.
SECTION I — IMMUNE LINES, WBCS, ANTIBODIES, HIV, GI & SKIN INFECTIONS Questions 1 – 25
1. The host's three lines of defense are sequentially organized. Which correctly lists the components of each line?
A. 1st line — B and T cells; 2nd line — physical barriers; 3rd line — fever
B. 1st line — physical and chemical barriers (innate/nonspecific); 2nd line — phagocytosis, inflammation, fever, antimicrobial proteins (innate/nonspecific); 3rd line — B
and T cells (acquired/specific)
C. 1st line — antimicrobial proteins; 2nd line — skin; 3rd line — inflammation
D. All three lines are identical in function and timing
CORRECT ANSWER B — 1st line: physical and chemical barriers (innate/nonspecific); 2nd line: phagocytosis, inflammation, fever, antimicrobial proteins (innate/nonspecific);
3rd line: B and T cells (acquired/specific)
RATIONALE The three lines of defense: First line (innate/nonspecific) — physical barriers (skin, mucous membranes) and chemical barriers (lysozyme, sweat, pH, HCl, bile,
resident microbiota). Second line (innate/nonspecific) — phagocytosis, inflammation (five signs: rubor/redness, calor/heat, tumor/swelling, dolor/pain, loss of
function), fever, antimicrobial proteins. Third line (acquired/specific) — B and T cells with two key characteristics: specificity (highly specific to the antigen) and
memory (rapid mobilization of lymphocytes programmed to recall their first engagement).
2. White blood cells have distinct functions. Which of the following correctly pairs a WBC with its primary function?
A. Neutrophils — react early in inflammatory response to bacteria and damaged tissue; high count is a common sign of bacterial infection
B. Eosinophils — release histamine during allergic reactions; play a role in immune surveillance
C. Monocytes — smallest WBCs; produce antibodies in response to antigens
D. Macrophages — short-lived cells that cannot multiply; limited to the bloodstream
CORRECT ANSWER A — Neutrophils react early in the inflammatory response to bacteria, foreign materials, and damaged tissue; a high neutrophil count is a common sign of
bacterial infection
RATIONALE WBC functions: Neutrophils — react early in inflammatory response to bacteria and damaged tissue; high count signals bacterial infection. Eosinophils — attracted
to parasitic infections (helminths), play a minor phagocytic role, most involved in allergic reactions. Basophils — release histamine during allergic
reactions/asthma attacks; play a role in immune surveillance. Monocytes — largest WBCs, cytoplasm holds granules with digestive enzymes, discharged by bone
marrow into bloodstream. Macrophages — monocytes that have left circulation; long-lived, able to multiply, among the most versatile cells. Plasma cells —
produce antibodies.
3. T cells and B cells mature in different locations. T helper cells, regulatory T cells, and cytotoxic T cells have distinct functions. Which statement is correct?
A. T cells mature in bone marrow; B cells mature in the thymus
B. T helper cells — activate macrophages, assist B-cell processes, and help activate cytotoxic T cells; Regulatory T cells — control T cell response, control inflammation,
prevent autoimmunity; Cytotoxic T cells — destroy infected host cells and foreign cells
C. Cytotoxic T cells produce antibodies; T helper cells directly kill infected cells
D. All T cells perform identical functions in the immune response
CORRECT ANSWER B — T helper cells activate macrophages, assist B-cell processes, and help activate cytotoxic T cells; Regulatory T cells control T cell response, control
inflammation, and prevent autoimmunity; Cytotoxic T cells destroy infected host cells and other foreign cells
RATIONALE T cells mature in the thymus; B cells mature in bone marrow. T helper cells (CD4) — activate macrophages, assist B-cell processes, and help activate cytotoxic T
cells. Regulatory T cells — chemically/directly stimulate proliferation of other T cells, stimulate B cells already bound to antigen, control T cell response, control
inflammation, and prevent autoimmunity. Cytotoxic T cells (CD8) — destroy infected host cells and other foreign cells by secreting perforins and granzymes.
Plasma cells produce antibodies. These distinct functions are essential to adaptive immunity.
, 4. The five classes of immunoglobulins (antibodies) have distinct characteristics. Which of the following is correct?
A. IgG — least abundant; cannot cross the placenta
B. IgM — pentamer (10 binding sites); first to respond to antigen; cannot cross the placenta
C. IgA — most abundant antibody in serum; crosses the placenta
D. IgE — most abundant antibody; first to respond to infection
CORRECT ANSWER B — IgM is a pentamer with 10 binding sites; it is the first antibody produced in response to antigen and cannot cross the placenta
RATIONALE The five immunoglobulins: IgG — most abundant (80% of serum antibodies), monomer (2 binding sites), CAN cross the placenta, provides long-term
immunity/memory. IgM — pentamer (10 binding sites), first to respond to antigen, serves as B-cell receptor, CANNOT cross placenta. IgA — secretory antibody on
mucous membranes, monomer (2 sites) or dimer (4 sites), CANNOT cross placenta. IgD — monomer (2 sites), receptor on B cells, CANNOT cross placenta. IgE —
least abundant, monomer (2 sites), antibody of allergy and worm infections, CANNOT cross placenta. Only IgG crosses the placenta.
5. The four types of acquired immunity are natural active, natural passive, artificial active, and artificial passive. Which example correctly matches each type?
A. Natural active — vaccination; Artificial active — breast milk
B. Natural active — having had an infectious disease (e.g., chickenpox); Natural passive — breast milk (prenatal/postnatal mother-child); Artificial active — vaccination;
Artificial passive — immunotherapy with specific antibodies
C. Natural passive — vaccination; Artificial passive — infection
D. All four types are identical and interchangeable
CORRECT ANSWER B — Natural active: infection; Natural passive: breast milk/mother-child; Artificial active: vaccination; Artificial passive: immunotherapy
RATIONALE The four types of acquired immunity: (1) Natural active immunity — acquired from having had an infectious disease (produces one's own antibodies after natural
exposure). (2) Natural passive immunity — acquired through prenatal/postnatal mother-child relationship (IgG across placenta, IgA in breast milk). (3) Artificial
active immunity — acquired from vaccinations (purposeful induction of antibody production). (4) Artificial passive immunity — immunotherapy using specific
antibodies against a particular infectious agent (injection of pre-formed antibodies). The CDC (Centers for Disease Control) is responsible for controlling the
introduction and spread of infectious diseases.
6. Staphylococcus aureus is a Gram-positive organism affecting which body system, and what infections does it cause?
A. Respiratory system — pneumonia and bronchitis only
B. Skin — cellulitis, atopic dermatitis, necrotizing fasciitis, impetigo, folliculitis, meningitis, osteomyelitis, and sepsis
C. Gastrointestinal system — ulcers and gastroenteritis
D. Nervous system — meningitis only
CORRECT ANSWER B — Skin — cellulitis, atopic dermatitis, necrotizing fasciitis, impetigo, folliculitis, meningitis, osteomyelitis, and sepsis
RATIONALE Staphylococcus aureus (Gram-positive, grape-like clusters) primarily affects the skin but can cause systemic infections including: cellulitis, atopic dermatitis,
necrotizing fasciitis (along with S. pyogenes), impetigo (along with S. pyogenes), folliculitis, meningitis, osteomyelitis, and sepsis. S. aureus exotoxins can cause
food poisoning through intoxication — the bacteria are killed by cooking, but the heat-stable toxins are NOT destroyed and remain capable of causing illness.
Streptococcal pharyngitis is caused by Streptococcus pyogenes. Diphtheria is caused by Corynebacterium diphtheriae (Gram-positive, club-shaped).
7. Measles (rubeola) is associated with which characteristic clinical finding?
A. Bull's eye rash at the site of a tick bite
B. Koplik spots — tiny white dots surrounded by a ring of red on the oral mucosa, along with a rash beginning on the head and spreading downward
C. Pseudomembrane formation on the tonsils or pharynx
D. Rice-water stool with severe dehydration
CORRECT ANSWER B — Koplik spots (tiny white dots with red ring on oral mucosa), rash beginning on head and spreading downward, fever, sore throat, conjunctivitis
RATIONALE Koplik spots are the pathognomonic oral lesions of measles (rubeola) — tiny white dots surrounded by a ring of red appearing before the characteristic rash.
Option A describes Lyme disease (Borrelia burgdorferi). Option C describes diphtheria (Corynebacterium diphtheriae — pseudomembrane on tonsils/pharynx,
treated with antitoxin + penicillin). Option D describes cholera (Vibrio cholerae — comma-shaped rod, rice-water stool, loss of blood volume, acidosis, shock).
Chickenpox (HHV-3) causes fluid-filled lesions; reactivation causes shingles (asymmetrical lesions on trunk/head, triggered by stress).
8. Ocular trachoma is a major cause of preventable blindness worldwide. It is caused by:
A. Staphylococcus aureus — a Gram-positive skin pathogen
B. Chlamydia trachomatis — causing chronic conjunctivitis with scarring and trichiasis
C. Neisseria gonorrhoeae — a sexually transmitted bacterium
D. Herpes simplex virus — causing corneal ulceration
CORRECT ANSWER B — Chlamydia trachomatis — causing chronic conjunctivitis leading to scarring, trichiasis, and blindness
RATIONALE Ocular trachoma is caused by Chlamydia trachomatis (serovars A–C). It is the leading infectious cause of preventable blindness worldwide, primarily affecting
children in developing countries. After repeated infections, scarring of the inner eyelid causes trichiasis (eyelashes turn inward and scratch the cornea), leading to
opacity and blindness. Prevention uses the SAFE strategy. A prion is an infectious protein containing no genetic material that causes transmissible spongiform
encephalopathies (CJD, BSE, scrapie, kuru, fatal familial insomnia).
★ ★
Chamberlain University
C College of Nursing & Health Professions
J O U R N E Y T O E X T R A O R D I N A R Y CO M PA S S I O N AT E C A R E
EST. 1889
BIOS 242 — Exam 3 Comprehensive Study Guide
I M M U N E SYST E M · W B CS · A N T I B O D I E S · I N F E C T I O U S D I S E A S E S · H I V · SY P H I L I S · G I & S K I N I N F E C T I O N S
INSTITUTION Chamberlain University COURSE CODE BIOS 242
PROGRAM Bachelor of Science in Nursing (BSN) ACADEMIC YEAR
RESOURCE TYPE Comprehensive Study Guide / Practice Examination TOTAL QUESTIONS 25 Questions
COURSE TITLE Fundamentals of Microbiology FORMAT Multiple Choice — Select the Single Best Answer
STUDY GUIDE INSTRUCTIONS
▸ Select the single best answer for each question unless otherwise instructed.
▸ This study guide covers the three lines of immune defense, WBC functions, antibody classes, T/B cell roles, and major infectious diseases.
▸ All content reflects BIOS 242 learning objectives for Exam 3.
▸ Correct answers and detailed rationales appear below each question for comprehensive exam preparation.
▸ Pay careful attention to immune cell functions, immunoglobulin characteristics, and disease-specific causative agents.
SECTION I — IMMUNE LINES, WBCS, ANTIBODIES, HIV, GI & SKIN INFECTIONS Questions 1 – 25
1. The host's three lines of defense are sequentially organized. Which correctly lists the components of each line?
A. 1st line — B and T cells; 2nd line — physical barriers; 3rd line — fever
B. 1st line — physical and chemical barriers (innate/nonspecific); 2nd line — phagocytosis, inflammation, fever, antimicrobial proteins (innate/nonspecific); 3rd line — B
and T cells (acquired/specific)
C. 1st line — antimicrobial proteins; 2nd line — skin; 3rd line — inflammation
D. All three lines are identical in function and timing
CORRECT ANSWER B — 1st line: physical and chemical barriers (innate/nonspecific); 2nd line: phagocytosis, inflammation, fever, antimicrobial proteins (innate/nonspecific);
3rd line: B and T cells (acquired/specific)
RATIONALE The three lines of defense: First line (innate/nonspecific) — physical barriers (skin, mucous membranes) and chemical barriers (lysozyme, sweat, pH, HCl, bile,
resident microbiota). Second line (innate/nonspecific) — phagocytosis, inflammation (five signs: rubor/redness, calor/heat, tumor/swelling, dolor/pain, loss of
function), fever, antimicrobial proteins. Third line (acquired/specific) — B and T cells with two key characteristics: specificity (highly specific to the antigen) and
memory (rapid mobilization of lymphocytes programmed to recall their first engagement).
2. White blood cells have distinct functions. Which of the following correctly pairs a WBC with its primary function?
A. Neutrophils — react early in inflammatory response to bacteria and damaged tissue; high count is a common sign of bacterial infection
B. Eosinophils — release histamine during allergic reactions; play a role in immune surveillance
C. Monocytes — smallest WBCs; produce antibodies in response to antigens
D. Macrophages — short-lived cells that cannot multiply; limited to the bloodstream
CORRECT ANSWER A — Neutrophils react early in the inflammatory response to bacteria, foreign materials, and damaged tissue; a high neutrophil count is a common sign of
bacterial infection
RATIONALE WBC functions: Neutrophils — react early in inflammatory response to bacteria and damaged tissue; high count signals bacterial infection. Eosinophils — attracted
to parasitic infections (helminths), play a minor phagocytic role, most involved in allergic reactions. Basophils — release histamine during allergic
reactions/asthma attacks; play a role in immune surveillance. Monocytes — largest WBCs, cytoplasm holds granules with digestive enzymes, discharged by bone
marrow into bloodstream. Macrophages — monocytes that have left circulation; long-lived, able to multiply, among the most versatile cells. Plasma cells —
produce antibodies.
3. T cells and B cells mature in different locations. T helper cells, regulatory T cells, and cytotoxic T cells have distinct functions. Which statement is correct?
A. T cells mature in bone marrow; B cells mature in the thymus
B. T helper cells — activate macrophages, assist B-cell processes, and help activate cytotoxic T cells; Regulatory T cells — control T cell response, control inflammation,
prevent autoimmunity; Cytotoxic T cells — destroy infected host cells and foreign cells
C. Cytotoxic T cells produce antibodies; T helper cells directly kill infected cells
D. All T cells perform identical functions in the immune response
CORRECT ANSWER B — T helper cells activate macrophages, assist B-cell processes, and help activate cytotoxic T cells; Regulatory T cells control T cell response, control
inflammation, and prevent autoimmunity; Cytotoxic T cells destroy infected host cells and other foreign cells
RATIONALE T cells mature in the thymus; B cells mature in bone marrow. T helper cells (CD4) — activate macrophages, assist B-cell processes, and help activate cytotoxic T
cells. Regulatory T cells — chemically/directly stimulate proliferation of other T cells, stimulate B cells already bound to antigen, control T cell response, control
inflammation, and prevent autoimmunity. Cytotoxic T cells (CD8) — destroy infected host cells and other foreign cells by secreting perforins and granzymes.
Plasma cells produce antibodies. These distinct functions are essential to adaptive immunity.
, 4. The five classes of immunoglobulins (antibodies) have distinct characteristics. Which of the following is correct?
A. IgG — least abundant; cannot cross the placenta
B. IgM — pentamer (10 binding sites); first to respond to antigen; cannot cross the placenta
C. IgA — most abundant antibody in serum; crosses the placenta
D. IgE — most abundant antibody; first to respond to infection
CORRECT ANSWER B — IgM is a pentamer with 10 binding sites; it is the first antibody produced in response to antigen and cannot cross the placenta
RATIONALE The five immunoglobulins: IgG — most abundant (80% of serum antibodies), monomer (2 binding sites), CAN cross the placenta, provides long-term
immunity/memory. IgM — pentamer (10 binding sites), first to respond to antigen, serves as B-cell receptor, CANNOT cross placenta. IgA — secretory antibody on
mucous membranes, monomer (2 sites) or dimer (4 sites), CANNOT cross placenta. IgD — monomer (2 sites), receptor on B cells, CANNOT cross placenta. IgE —
least abundant, monomer (2 sites), antibody of allergy and worm infections, CANNOT cross placenta. Only IgG crosses the placenta.
5. The four types of acquired immunity are natural active, natural passive, artificial active, and artificial passive. Which example correctly matches each type?
A. Natural active — vaccination; Artificial active — breast milk
B. Natural active — having had an infectious disease (e.g., chickenpox); Natural passive — breast milk (prenatal/postnatal mother-child); Artificial active — vaccination;
Artificial passive — immunotherapy with specific antibodies
C. Natural passive — vaccination; Artificial passive — infection
D. All four types are identical and interchangeable
CORRECT ANSWER B — Natural active: infection; Natural passive: breast milk/mother-child; Artificial active: vaccination; Artificial passive: immunotherapy
RATIONALE The four types of acquired immunity: (1) Natural active immunity — acquired from having had an infectious disease (produces one's own antibodies after natural
exposure). (2) Natural passive immunity — acquired through prenatal/postnatal mother-child relationship (IgG across placenta, IgA in breast milk). (3) Artificial
active immunity — acquired from vaccinations (purposeful induction of antibody production). (4) Artificial passive immunity — immunotherapy using specific
antibodies against a particular infectious agent (injection of pre-formed antibodies). The CDC (Centers for Disease Control) is responsible for controlling the
introduction and spread of infectious diseases.
6. Staphylococcus aureus is a Gram-positive organism affecting which body system, and what infections does it cause?
A. Respiratory system — pneumonia and bronchitis only
B. Skin — cellulitis, atopic dermatitis, necrotizing fasciitis, impetigo, folliculitis, meningitis, osteomyelitis, and sepsis
C. Gastrointestinal system — ulcers and gastroenteritis
D. Nervous system — meningitis only
CORRECT ANSWER B — Skin — cellulitis, atopic dermatitis, necrotizing fasciitis, impetigo, folliculitis, meningitis, osteomyelitis, and sepsis
RATIONALE Staphylococcus aureus (Gram-positive, grape-like clusters) primarily affects the skin but can cause systemic infections including: cellulitis, atopic dermatitis,
necrotizing fasciitis (along with S. pyogenes), impetigo (along with S. pyogenes), folliculitis, meningitis, osteomyelitis, and sepsis. S. aureus exotoxins can cause
food poisoning through intoxication — the bacteria are killed by cooking, but the heat-stable toxins are NOT destroyed and remain capable of causing illness.
Streptococcal pharyngitis is caused by Streptococcus pyogenes. Diphtheria is caused by Corynebacterium diphtheriae (Gram-positive, club-shaped).
7. Measles (rubeola) is associated with which characteristic clinical finding?
A. Bull's eye rash at the site of a tick bite
B. Koplik spots — tiny white dots surrounded by a ring of red on the oral mucosa, along with a rash beginning on the head and spreading downward
C. Pseudomembrane formation on the tonsils or pharynx
D. Rice-water stool with severe dehydration
CORRECT ANSWER B — Koplik spots (tiny white dots with red ring on oral mucosa), rash beginning on head and spreading downward, fever, sore throat, conjunctivitis
RATIONALE Koplik spots are the pathognomonic oral lesions of measles (rubeola) — tiny white dots surrounded by a ring of red appearing before the characteristic rash.
Option A describes Lyme disease (Borrelia burgdorferi). Option C describes diphtheria (Corynebacterium diphtheriae — pseudomembrane on tonsils/pharynx,
treated with antitoxin + penicillin). Option D describes cholera (Vibrio cholerae — comma-shaped rod, rice-water stool, loss of blood volume, acidosis, shock).
Chickenpox (HHV-3) causes fluid-filled lesions; reactivation causes shingles (asymmetrical lesions on trunk/head, triggered by stress).
8. Ocular trachoma is a major cause of preventable blindness worldwide. It is caused by:
A. Staphylococcus aureus — a Gram-positive skin pathogen
B. Chlamydia trachomatis — causing chronic conjunctivitis with scarring and trichiasis
C. Neisseria gonorrhoeae — a sexually transmitted bacterium
D. Herpes simplex virus — causing corneal ulceration
CORRECT ANSWER B — Chlamydia trachomatis — causing chronic conjunctivitis leading to scarring, trichiasis, and blindness
RATIONALE Ocular trachoma is caused by Chlamydia trachomatis (serovars A–C). It is the leading infectious cause of preventable blindness worldwide, primarily affecting
children in developing countries. After repeated infections, scarring of the inner eyelid causes trichiasis (eyelashes turn inward and scratch the cornea), leading to
opacity and blindness. Prevention uses the SAFE strategy. A prion is an infectious protein containing no genetic material that causes transmissible spongiform
encephalopathies (CJD, BSE, scrapie, kuru, fatal familial insomnia).
