Microbiology with Lab - Week 8 Comprehensive Quiz 2026 |WGU
1. Which component of the immune system is considered the first line of
defense?
A. Phagocytic white blood cells
B. Intact skin and mucous membranes
C. The inflammatory response
D. Production of antibodies
Answer: B
Rationale: The first line of defense consists of physical and chemical barriers like the skin
and mucous membranes that prevent pathogen entry.
2. What is the primary function of neutrophils in the innate immune response?
A. Phagocytosis of invading microorganisms
B. Presentation of antigens to T cells
C. Production of histamine
D. Killing of virus-infected cells by apoptosis
Answer: A
Rationale: Neutrophils are highly phagocytic granulocytes that are typically the first cells
to arrive at the site of an infection.
,3. Which process involves the coating of a pathogen with proteins to enhance
phagocytosis?
A. Chemotaxis
B. Opsonization
C. Apoptosis
D. Agglutination
Answer: B
Rationale: Opsonization is the process where complement proteins or antibodies coat a
microorganism, making it easier for phagocytes to bind and ingest.
4. The ‘Alternative Pathway’ of the complement system is activated by:
A. Antigen-antibody complexes
B. Direct contact with lipid-carbohydrate complexes on a microbe
C. Lectin binding to mannose
D. Cytokines released by Helper T cells
Answer: B
Rationale: Unlike the classical pathway which requires antibodies, the alternative pathway
is triggered by direct interaction with microbial surface molecules.
5. Which complement protein is responsible for forming the Membrane Attack
Complex (MAC)?
A. C3b
B. C5a
C. C1
D. C9
Answer: D
Rationale: C5b through C9 assemble to form the MAC, which creates pores in the target
cell membrane, leading to lysis.
, 6. What is the primary effect of histamine release during the inflammatory
response?
A. Decreased vascular permeability
B. Vasodilation and increased permeability of blood vessels
C. Activation of the complement cascade
D. Systemic increase in body temperature
Answer: B
Rationale: Histamine causes blood vessels to dilate and become ‘leaky,’ allowing immune
cells and fluid to reach the site of injury.
7. Which type of interferon is primarily involved in inducing antiviral states in
neighboring cells?
A. Interferon-alpha
B. Interferon-gamma
C. Interleukin-1
D. Tumor Necrosis Factor
Answer: A
Rationale: Interferon-alpha and Beta are produced by virus-infected cells to signal
neighboring cells to produce antiviral proteins.
8. Which of the following is a characteristic of adaptive immunity but NOT
innate immunity?
A. Immediate response to infection
B. Memory of specific pathogens
C. Presence at birth
D. Physical barriers to entry
Answer: B
Rationale: Adaptive immunity is characterized by specificity and memory, meaning it
‘remembers’ a pathogen for a faster response upon re-exposure.
1. Which component of the immune system is considered the first line of
defense?
A. Phagocytic white blood cells
B. Intact skin and mucous membranes
C. The inflammatory response
D. Production of antibodies
Answer: B
Rationale: The first line of defense consists of physical and chemical barriers like the skin
and mucous membranes that prevent pathogen entry.
2. What is the primary function of neutrophils in the innate immune response?
A. Phagocytosis of invading microorganisms
B. Presentation of antigens to T cells
C. Production of histamine
D. Killing of virus-infected cells by apoptosis
Answer: A
Rationale: Neutrophils are highly phagocytic granulocytes that are typically the first cells
to arrive at the site of an infection.
,3. Which process involves the coating of a pathogen with proteins to enhance
phagocytosis?
A. Chemotaxis
B. Opsonization
C. Apoptosis
D. Agglutination
Answer: B
Rationale: Opsonization is the process where complement proteins or antibodies coat a
microorganism, making it easier for phagocytes to bind and ingest.
4. The ‘Alternative Pathway’ of the complement system is activated by:
A. Antigen-antibody complexes
B. Direct contact with lipid-carbohydrate complexes on a microbe
C. Lectin binding to mannose
D. Cytokines released by Helper T cells
Answer: B
Rationale: Unlike the classical pathway which requires antibodies, the alternative pathway
is triggered by direct interaction with microbial surface molecules.
5. Which complement protein is responsible for forming the Membrane Attack
Complex (MAC)?
A. C3b
B. C5a
C. C1
D. C9
Answer: D
Rationale: C5b through C9 assemble to form the MAC, which creates pores in the target
cell membrane, leading to lysis.
, 6. What is the primary effect of histamine release during the inflammatory
response?
A. Decreased vascular permeability
B. Vasodilation and increased permeability of blood vessels
C. Activation of the complement cascade
D. Systemic increase in body temperature
Answer: B
Rationale: Histamine causes blood vessels to dilate and become ‘leaky,’ allowing immune
cells and fluid to reach the site of injury.
7. Which type of interferon is primarily involved in inducing antiviral states in
neighboring cells?
A. Interferon-alpha
B. Interferon-gamma
C. Interleukin-1
D. Tumor Necrosis Factor
Answer: A
Rationale: Interferon-alpha and Beta are produced by virus-infected cells to signal
neighboring cells to produce antiviral proteins.
8. Which of the following is a characteristic of adaptive immunity but NOT
innate immunity?
A. Immediate response to infection
B. Memory of specific pathogens
C. Presence at birth
D. Physical barriers to entry
Answer: B
Rationale: Adaptive immunity is characterized by specificity and memory, meaning it
‘remembers’ a pathogen for a faster response upon re-exposure.
