BIO 4B – FINAL EXAM 2025 QUESTIONS
AND ANSWERS
True or False: Plants, fungi, and bacteria have immune responses. - ANS True
How do immune cells recognize pathogens? What kind of recognition? - ANS Innate
recognition and Adaptive recognition.
What is the kind of immunity that all animals have and how does it work? - ANS Innate
immunity. It's a defense active immediately upon infection. Including barriers like skin, mucous,
etc.
What is the immunity that only vertebrates have and how does it work? - ANS Adaptive
immunity. It's activated after the innate response and develops more slowly.
Give me an example of innate immunity and its steps. - ANS Phagocytosis.
1) Pseudopodia surround pathogens.
2) Pathogens are engulfed by endocytosis.
3) Vacuole forms.
4) Vacuole and lysosome fuse.
5) Pathogens destroyed.
6) Debris from pathogens released.
Explain the antiviral defense in insects. - ANS The virus infects the host cell. An enzyme
breaks up the viral RNA so it won't replicate.
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,Give me 3 cellular innate defenses in mammals - ANS 1) Innate immune cells detect, devour
and destroy invading pathogens: recognize pathogens using TLRs (toll-like receptors)
2) Phagocytic cells: neutrophils, eosinophils (white blood cells), macrophages, and dentritic
cells.
4) Natural Killer Cells (NKCs): circulating thourgh the body and detect abnormal cells, leading to
cell death inhibiting the spread of infected/cancerous cells.
How does an inflammatory response start and what are two signs of it? - ANS Signs: heat and
swelling
Mast cells discharge cytokines, recruiting neutrophils to the site. Mast cells release histamine,
triggering blood vessels to dilate and become more permeable. The increase in blood supply
produces the inflammatory response.
How can some pathogens avoid the innate immunity? - ANS Due to their outer capsule that
avoid molecular recognition and phagocytosis. i.e: Streptococcus pneumoniae (pneumonia and
meningitis) or M. tuberculosis (it's recognized but resists breakdown)
What is unique about adaptive immunity? - ANS Receptors provide pathogen-specific
recognition.
This is enhanced by previous exposure to the pathogen.
What are the two lymphocytes that the adaptive response relies on? Why are they named like
that? - ANS T cells (mature in thymus) and B cells (mature in bone marrow)
Differentiate the primary and secondary immune responses involved in immunological
memory. - ANS Primary immune response is the first exposure to antigen, therefore slower.
A clone of lymphocytes is formed that are specific to the pathogen.
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, Secondary immune response is faster, greated and more prolonged response from a reservoir
of T and B memory cells.
True or false: antibodies kill pathogens. - ANS False. Instead, they mark pathogens for
inactivation or destruction.
What are the antibodies function? - ANS Mark pathogens for inactivation or destruction,
neutralization by binding to viral surface proteins to avoid infection of a host cell, and B cells
can express 5 different forms of immunoglobulin (Ig) with similar antigen-binding specificity.
(IgD, IgA, IgE, IgG, IgM)
What kinds of vaccines are there against COVID? - ANS 1) Genetic-code vaccines
2) Viral vector vaccines
3) Subunit vaccines
4) Weakened/inactive vaccines
How do the Pfizer and Moderna vaccines work? - ANS They inject mRNA into your tissues.
Then your cell express that mRNA producing the specific spike protein found on COVID-19. Your
body will produce antibodies against that spike protein and if you get exposed to COVID-19,
your body can fight it!
What is the difference between active and passive immunity? - ANS Active immunity
develops naturally when a pathogen invades the body and elicits a primary or secondary
immune response
Passive immunity provides immediate, short-term protection from somebody else, such as a
mother to the fetus crossing the placenta (IgG) or to the baby through breast milk (IgA).
When can immune rejection occur? - ANS Cells transferred from one person to another, such
as in transplantation of tissues or organs. To minimize rejection, doctors use donor tissue with
COPYRIGHT © 2025 BRAINBARTER ALL RIGHTS RESERVED 3
AND ANSWERS
True or False: Plants, fungi, and bacteria have immune responses. - ANS True
How do immune cells recognize pathogens? What kind of recognition? - ANS Innate
recognition and Adaptive recognition.
What is the kind of immunity that all animals have and how does it work? - ANS Innate
immunity. It's a defense active immediately upon infection. Including barriers like skin, mucous,
etc.
What is the immunity that only vertebrates have and how does it work? - ANS Adaptive
immunity. It's activated after the innate response and develops more slowly.
Give me an example of innate immunity and its steps. - ANS Phagocytosis.
1) Pseudopodia surround pathogens.
2) Pathogens are engulfed by endocytosis.
3) Vacuole forms.
4) Vacuole and lysosome fuse.
5) Pathogens destroyed.
6) Debris from pathogens released.
Explain the antiviral defense in insects. - ANS The virus infects the host cell. An enzyme
breaks up the viral RNA so it won't replicate.
COPYRIGHT © 2025 BRAINBARTER ALL RIGHTS RESERVED 1
,Give me 3 cellular innate defenses in mammals - ANS 1) Innate immune cells detect, devour
and destroy invading pathogens: recognize pathogens using TLRs (toll-like receptors)
2) Phagocytic cells: neutrophils, eosinophils (white blood cells), macrophages, and dentritic
cells.
4) Natural Killer Cells (NKCs): circulating thourgh the body and detect abnormal cells, leading to
cell death inhibiting the spread of infected/cancerous cells.
How does an inflammatory response start and what are two signs of it? - ANS Signs: heat and
swelling
Mast cells discharge cytokines, recruiting neutrophils to the site. Mast cells release histamine,
triggering blood vessels to dilate and become more permeable. The increase in blood supply
produces the inflammatory response.
How can some pathogens avoid the innate immunity? - ANS Due to their outer capsule that
avoid molecular recognition and phagocytosis. i.e: Streptococcus pneumoniae (pneumonia and
meningitis) or M. tuberculosis (it's recognized but resists breakdown)
What is unique about adaptive immunity? - ANS Receptors provide pathogen-specific
recognition.
This is enhanced by previous exposure to the pathogen.
What are the two lymphocytes that the adaptive response relies on? Why are they named like
that? - ANS T cells (mature in thymus) and B cells (mature in bone marrow)
Differentiate the primary and secondary immune responses involved in immunological
memory. - ANS Primary immune response is the first exposure to antigen, therefore slower.
A clone of lymphocytes is formed that are specific to the pathogen.
COPYRIGHT © 2025 BRAINBARTER ALL RIGHTS RESERVED 2
, Secondary immune response is faster, greated and more prolonged response from a reservoir
of T and B memory cells.
True or false: antibodies kill pathogens. - ANS False. Instead, they mark pathogens for
inactivation or destruction.
What are the antibodies function? - ANS Mark pathogens for inactivation or destruction,
neutralization by binding to viral surface proteins to avoid infection of a host cell, and B cells
can express 5 different forms of immunoglobulin (Ig) with similar antigen-binding specificity.
(IgD, IgA, IgE, IgG, IgM)
What kinds of vaccines are there against COVID? - ANS 1) Genetic-code vaccines
2) Viral vector vaccines
3) Subunit vaccines
4) Weakened/inactive vaccines
How do the Pfizer and Moderna vaccines work? - ANS They inject mRNA into your tissues.
Then your cell express that mRNA producing the specific spike protein found on COVID-19. Your
body will produce antibodies against that spike protein and if you get exposed to COVID-19,
your body can fight it!
What is the difference between active and passive immunity? - ANS Active immunity
develops naturally when a pathogen invades the body and elicits a primary or secondary
immune response
Passive immunity provides immediate, short-term protection from somebody else, such as a
mother to the fetus crossing the placenta (IgG) or to the baby through breast milk (IgA).
When can immune rejection occur? - ANS Cells transferred from one person to another, such
as in transplantation of tissues or organs. To minimize rejection, doctors use donor tissue with
COPYRIGHT © 2025 BRAINBARTER ALL RIGHTS RESERVED 3
