BIOD 331 Module 4 Exam Portage Learning Questions and
Answers 2026
1. Which of the following is a component of "Innate Immunity"?
A) B-lymphocytes
B) T-lymphocytes
C) Natural Killer (NK) cells
D) Memory cells
Answer: C
Rationale: NK cells, phagocytes, and physical barriers like the skin are non-specific
innate defenses.
2. Which organ is the primary site for "T-cell maturation"?
A) Bone Marrow
B) Thymus
C) Spleen
D) Lymph Nodes
Answer: B
Rationale: T-cells originat
e in the bone marrow but migrate to the thymus to mature and become
immunocompetent.
3. "Humoral Immunity" is primarily mediated by:
A) Cytotoxic T-cells
B) Antibodies produced by B-cells
C) Macrophages
D) Epithelial cells
Answer: B
Rationale: Humoral immunity involves B-cells differentiating into plasma cells that
secrete antibodies into body fluids (humors).
4. Which antibody (immunoglobulin) is the most abundant and can cross the
placenta?
A) IgA
B) IgE
C) IgG
D) IgM
Answer: C
,Rationale: IgG provides passive immunity to the fetus and is the primary antibody in the
secondary immune response.
5. "Type I Hypersensitivity" reactions are mediated by which antibody?
A) IgG
B) IgM
C) IgE
D) IgD
Answer: C
Rationale: IgE binds to mast cells, triggering the release of histamine in allergic
reactions (anaphylaxis).
6. An "Opportunistic Infection" occurs when:
A) The immune system is hyperactive.
B) A pathogen that normally doesn't cause disease infects an immunocompromised
host.
C) A healthy person gets a cold.
D) A vaccine is administered.
Answer: B
Rationale: This is a hallmark of advanced HIV/AIDS where the CD4 count is very low.
7. Which cell type is the "Master Switch" of the immune system and is targeted by
HIV?
A) CD8+ Cytotoxic T-cells
B) B-lymphocytes
C) CD4+ Helper T-cells
D) Neutrophils
Answer: C
Rationale: CD4 cells coordinate both the humoral and cell-mediated immune responses.
8. "MHC II" molecules are found only on:
A) All nucleated cells.
B) Red blood cells.
C) Antigen-Presenting Cells (APCs) like macrophages and dendritic cells.
D) Platelets.
Answer: C
Rationale: APCs use MHC II to "show" captured antigens to Helper T-cells.
9. A person receiving a "Flu Vaccine" develops which type of immunity?
A) Natural Passive
B) Natural Active
, C) Artificial Passive
D) Artificial Active
Answer: D
Rationale: The vaccine (artificial) triggers the body to produce its own (active)
antibodies and memory cells.
10. "Anaphylaxis" is a life-threatening example of which hypersensitivity?
A) Type I (Immediate)
B) Type II (Antibody-mediated)
C) Type III (Immune complex)
D) Type IV (Delayed)
Answer: A
Rationale: It involves systemic vasodilation and bronchoconstriction triggered by IgE-
mediated mast cell degranulation.
11. Which antibody is found primarily in secretions like colostrum, saliva, and
tears?
A) IgG
B) IgA
C) IgM
D) IgE
Answer: B
Rationale: IgA provides "mucosal immunity" at the body's points of entry.
12. "Autoimmunity" occurs when:
A) The immune system is too weak.
B) The immune system loses the ability to differentiate between self and non-self
antigens.
C) A person receives a transplant.
D) Antibodies are passed from mother to baby.
Answer: B
Rationale: The body attacks its own tissues (e.g., Rheumatoid Arthritis, Lupus).
13. Which type of hypersensitivity involves "Immune Complexes" depositing in
blood vessel walls?
A) Type I
B) Type II
C) Type III
D) Type IV
Answer: C
Answers 2026
1. Which of the following is a component of "Innate Immunity"?
A) B-lymphocytes
B) T-lymphocytes
C) Natural Killer (NK) cells
D) Memory cells
Answer: C
Rationale: NK cells, phagocytes, and physical barriers like the skin are non-specific
innate defenses.
2. Which organ is the primary site for "T-cell maturation"?
A) Bone Marrow
B) Thymus
C) Spleen
D) Lymph Nodes
Answer: B
Rationale: T-cells originat
e in the bone marrow but migrate to the thymus to mature and become
immunocompetent.
3. "Humoral Immunity" is primarily mediated by:
A) Cytotoxic T-cells
B) Antibodies produced by B-cells
C) Macrophages
D) Epithelial cells
Answer: B
Rationale: Humoral immunity involves B-cells differentiating into plasma cells that
secrete antibodies into body fluids (humors).
4. Which antibody (immunoglobulin) is the most abundant and can cross the
placenta?
A) IgA
B) IgE
C) IgG
D) IgM
Answer: C
,Rationale: IgG provides passive immunity to the fetus and is the primary antibody in the
secondary immune response.
5. "Type I Hypersensitivity" reactions are mediated by which antibody?
A) IgG
B) IgM
C) IgE
D) IgD
Answer: C
Rationale: IgE binds to mast cells, triggering the release of histamine in allergic
reactions (anaphylaxis).
6. An "Opportunistic Infection" occurs when:
A) The immune system is hyperactive.
B) A pathogen that normally doesn't cause disease infects an immunocompromised
host.
C) A healthy person gets a cold.
D) A vaccine is administered.
Answer: B
Rationale: This is a hallmark of advanced HIV/AIDS where the CD4 count is very low.
7. Which cell type is the "Master Switch" of the immune system and is targeted by
HIV?
A) CD8+ Cytotoxic T-cells
B) B-lymphocytes
C) CD4+ Helper T-cells
D) Neutrophils
Answer: C
Rationale: CD4 cells coordinate both the humoral and cell-mediated immune responses.
8. "MHC II" molecules are found only on:
A) All nucleated cells.
B) Red blood cells.
C) Antigen-Presenting Cells (APCs) like macrophages and dendritic cells.
D) Platelets.
Answer: C
Rationale: APCs use MHC II to "show" captured antigens to Helper T-cells.
9. A person receiving a "Flu Vaccine" develops which type of immunity?
A) Natural Passive
B) Natural Active
, C) Artificial Passive
D) Artificial Active
Answer: D
Rationale: The vaccine (artificial) triggers the body to produce its own (active)
antibodies and memory cells.
10. "Anaphylaxis" is a life-threatening example of which hypersensitivity?
A) Type I (Immediate)
B) Type II (Antibody-mediated)
C) Type III (Immune complex)
D) Type IV (Delayed)
Answer: A
Rationale: It involves systemic vasodilation and bronchoconstriction triggered by IgE-
mediated mast cell degranulation.
11. Which antibody is found primarily in secretions like colostrum, saliva, and
tears?
A) IgG
B) IgA
C) IgM
D) IgE
Answer: B
Rationale: IgA provides "mucosal immunity" at the body's points of entry.
12. "Autoimmunity" occurs when:
A) The immune system is too weak.
B) The immune system loses the ability to differentiate between self and non-self
antigens.
C) A person receives a transplant.
D) Antibodies are passed from mother to baby.
Answer: B
Rationale: The body attacks its own tissues (e.g., Rheumatoid Arthritis, Lupus).
13. Which type of hypersensitivity involves "Immune Complexes" depositing in
blood vessel walls?
A) Type I
B) Type II
C) Type III
D) Type IV
Answer: C
