ESTUDYR
BIOL 102 CHAPTER 43 UPDATED EXAM WITH MOST TESTED
QUESTIONS AND ANSWERS | GRADED A+ | ASSURED SUCCESS
WITH DETAILED RATIONALES
1. Which secretion is not a barrier that prevents pathogens from entering the body?
A. Ear wax
B. Mucus
C. Lysozyme
D. Antigens
Answer: D. Antigens. ✔
Rationale: Antigens are molecules that elicit immune responses, not physical/chemical
barriers like mucus, lysozyme, or earwax.
2. True or false? The leukocytes of the innate immune system are B cells, macrophages,
and neutrophils.
A. True
B. False ✔
Rationale: B cells are adaptive immune lymphocytes; innate leukocytes include
macrophages and neutrophils but not B cells.
3. How do cells involved in the innate immune response detect the presence of
pathogens?
A. Leukocytes recognize secretions from a pathogen.
B. Leukocytes recognize unique molecules on pathogens. ✔
C. Antibodies bind to the pathogens.
D. Leukocytes recognize the entire pathogen.
Rationale: Innate cells use pattern recognition receptors (e.g., TLRs) to detect conserved
microbial molecules (PAMPs).
4. Which of the following cells can engulf a pathogen?
A. Cytokines
B. Macrophages ✔
C. Mast cells
D. Platelets
Rationale: Macrophages are professional phagocytes; cytokines are signaling molecules,
mast cells release mediators, platelets clot.
,ESTUDYR
5. Which statement best describes mast cell role in inflammation?
A. They release chemicals that dilate blood vessels near the wound site, allowing blood
components to enter the region.
B. They release chemicals that constrict blood vessels elsewhere.
C. They secrete substances that degrade bacterial walls and engulf invaders.
D. They release cytokines to stimulate neutrophils and macrophages.
Answer: A. They release chemicals that dilate blood vessels near the wound site,
allowing blood components to enter the region. ✔
Rationale: Mast cells release histamine and other mediators that increase local blood
flow and vascular permeability.
6. Which event occurs first after a skin wound?
A. Macrophages present bacterial proteins as antigens.
B. Mast cells secrete chemical messengers to regulate blood flow to the wound. ✔
C. Neutrophils secrete substances that degrade bacterial walls.
D. Platelets release proteins that form clots.
Rationale: Platelet clotting and mast cell mediator release are immediate; the question
asks “first” — clotting and mast cell release occur essentially immediately. The original
answer selected platelets in the source; either way, clot formation (platelet proteins)
prevents bleeding and occurs immediately. (Note: both platelet clotting and mast cell
mediators occur very early; primary hemostasis by platelets is typically the immediate
first event).
7. The site of inflammation may become swollen due to increased cells/fluids and painful
due to pain receptor signaling.
A. True ✔
B. False
Rationale: Vascular permeability and immune cell influx cause swelling; mediators
sensitize pain receptors.
8. Innate immunity and adaptive immunity are both ________.
A. dependent exclusively on cell-mediated responses
B. characteristics of all vertebrate animals
C. dependent on tears, saliva, and mucous secretions
D. dependent on surface secretions from sebaceous and sweat glands
Answer: B. characteristics of all vertebrate animals. ✔
Rationale: Both systems are components of vertebrate immune defense (note: innate is
universal across animals; adaptive is characteristic of vertebrates).
, ESTUDYR
9. An antigen __________.
A. is a protein molecule that helps defend the body
B. induces development of white blood cells in bone marrow
C. is a molecule that evokes an immune response by a lymphocyte. ✔
D. could be an invading bacterium
Rationale: An antigen is any molecule (often protein or polysaccharide) that elicits an
adaptive immune response; whole organisms can carry antigens, but the definition is
molecule-based.
10. The ~1 million possible B-cell antigen receptors arise from ________.
A. temporary RNA splicing changes
B. continual splicing after differentiation
C. recombination of the DNA segments that make up the functional receptor genes ✔
D. having one million different immunoglobulin genes
Rationale: V(D)J recombination in developing B cells generates receptor diversity.
11. True or False? The words "antigen" and "virus" are interchangeable.
A. True
B. False ✔
Rationale: A virus is an organism/particle; antigens are molecules (from viruses,
bacteria, etc.) that stimulate adaptive responses.
12. A man tests positive for virus presence but has no detectable corresponding antibodies.
What might this mean?
A. He was exposed within the past two weeks.
B. He was probably exposed a few days ago and clonal selection has yet to produce
plasma cells. ✔
C. He was exposed several months ago and antibodies ceased.
D. Insufficient information.
Rationale: Antibody production lags behind infection; early detection of virus before
antibody seroconversion is common.
13. Which is true about memory cells?
A. They have a longer lifespan than plasma cells. ✔
B. They engulf antigens.
C. They produce antibodies.
D. First time an antigen is encountered, they become plasma cells.
Rationale: Memory lymphocytes are long-lived and persist to mediate faster secondary
responses.
BIOL 102 CHAPTER 43 UPDATED EXAM WITH MOST TESTED
QUESTIONS AND ANSWERS | GRADED A+ | ASSURED SUCCESS
WITH DETAILED RATIONALES
1. Which secretion is not a barrier that prevents pathogens from entering the body?
A. Ear wax
B. Mucus
C. Lysozyme
D. Antigens
Answer: D. Antigens. ✔
Rationale: Antigens are molecules that elicit immune responses, not physical/chemical
barriers like mucus, lysozyme, or earwax.
2. True or false? The leukocytes of the innate immune system are B cells, macrophages,
and neutrophils.
A. True
B. False ✔
Rationale: B cells are adaptive immune lymphocytes; innate leukocytes include
macrophages and neutrophils but not B cells.
3. How do cells involved in the innate immune response detect the presence of
pathogens?
A. Leukocytes recognize secretions from a pathogen.
B. Leukocytes recognize unique molecules on pathogens. ✔
C. Antibodies bind to the pathogens.
D. Leukocytes recognize the entire pathogen.
Rationale: Innate cells use pattern recognition receptors (e.g., TLRs) to detect conserved
microbial molecules (PAMPs).
4. Which of the following cells can engulf a pathogen?
A. Cytokines
B. Macrophages ✔
C. Mast cells
D. Platelets
Rationale: Macrophages are professional phagocytes; cytokines are signaling molecules,
mast cells release mediators, platelets clot.
,ESTUDYR
5. Which statement best describes mast cell role in inflammation?
A. They release chemicals that dilate blood vessels near the wound site, allowing blood
components to enter the region.
B. They release chemicals that constrict blood vessels elsewhere.
C. They secrete substances that degrade bacterial walls and engulf invaders.
D. They release cytokines to stimulate neutrophils and macrophages.
Answer: A. They release chemicals that dilate blood vessels near the wound site,
allowing blood components to enter the region. ✔
Rationale: Mast cells release histamine and other mediators that increase local blood
flow and vascular permeability.
6. Which event occurs first after a skin wound?
A. Macrophages present bacterial proteins as antigens.
B. Mast cells secrete chemical messengers to regulate blood flow to the wound. ✔
C. Neutrophils secrete substances that degrade bacterial walls.
D. Platelets release proteins that form clots.
Rationale: Platelet clotting and mast cell mediator release are immediate; the question
asks “first” — clotting and mast cell release occur essentially immediately. The original
answer selected platelets in the source; either way, clot formation (platelet proteins)
prevents bleeding and occurs immediately. (Note: both platelet clotting and mast cell
mediators occur very early; primary hemostasis by platelets is typically the immediate
first event).
7. The site of inflammation may become swollen due to increased cells/fluids and painful
due to pain receptor signaling.
A. True ✔
B. False
Rationale: Vascular permeability and immune cell influx cause swelling; mediators
sensitize pain receptors.
8. Innate immunity and adaptive immunity are both ________.
A. dependent exclusively on cell-mediated responses
B. characteristics of all vertebrate animals
C. dependent on tears, saliva, and mucous secretions
D. dependent on surface secretions from sebaceous and sweat glands
Answer: B. characteristics of all vertebrate animals. ✔
Rationale: Both systems are components of vertebrate immune defense (note: innate is
universal across animals; adaptive is characteristic of vertebrates).
, ESTUDYR
9. An antigen __________.
A. is a protein molecule that helps defend the body
B. induces development of white blood cells in bone marrow
C. is a molecule that evokes an immune response by a lymphocyte. ✔
D. could be an invading bacterium
Rationale: An antigen is any molecule (often protein or polysaccharide) that elicits an
adaptive immune response; whole organisms can carry antigens, but the definition is
molecule-based.
10. The ~1 million possible B-cell antigen receptors arise from ________.
A. temporary RNA splicing changes
B. continual splicing after differentiation
C. recombination of the DNA segments that make up the functional receptor genes ✔
D. having one million different immunoglobulin genes
Rationale: V(D)J recombination in developing B cells generates receptor diversity.
11. True or False? The words "antigen" and "virus" are interchangeable.
A. True
B. False ✔
Rationale: A virus is an organism/particle; antigens are molecules (from viruses,
bacteria, etc.) that stimulate adaptive responses.
12. A man tests positive for virus presence but has no detectable corresponding antibodies.
What might this mean?
A. He was exposed within the past two weeks.
B. He was probably exposed a few days ago and clonal selection has yet to produce
plasma cells. ✔
C. He was exposed several months ago and antibodies ceased.
D. Insufficient information.
Rationale: Antibody production lags behind infection; early detection of virus before
antibody seroconversion is common.
13. Which is true about memory cells?
A. They have a longer lifespan than plasma cells. ✔
B. They engulf antigens.
C. They produce antibodies.
D. First time an antigen is encountered, they become plasma cells.
Rationale: Memory lymphocytes are long-lived and persist to mediate faster secondary
responses.
