Bio 4B - Final Exam Questions and Answers Solved Correctly
True or False: Plants, fungi, and bacteria have immune responses. - Answers True
How do immune cells recognize pathogens? What kind of recognition? - Answers Innate recognition and
Adaptive recognition.
What is the kind of immunity that all animals have and how does it work? - Answers 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? - Answers Adaptive immunity.
It's activated after the innate response and develops more slowly.
Give me an example of innate immunity and its steps. - Answers 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. - Answers The virus infects the host cell. An enzyme breaks up
the viral RNA so it won't replicate.
Give me 3 cellular innate defenses in mammals - Answers 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? - Answers 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? - Answers 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? - Answers 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? -
Answers T cells (mature in thymus) and B cells (mature in bone marrow)
Differentiate the primary and secondary immune responses involved in immunological memory. -
Answers Primary immune response is the first exposure to antigen, therefore slower. A clone of
lymphocytes is formed that are specific to the pathogen.
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. - Answers False. Instead, they mark pathogens for inactivation or
destruction.
What are the antibodies function? - Answers 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? - Answers 1) Genetic-code vaccines
2) Viral vector vaccines
3) Subunit vaccines
4) Weakened/inactive vaccines
How do the Pfizer and Moderna vaccines work? - Answers 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? - Answers 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? - Answers Cells transferred from one person to another, such as in
transplantation of tissues or organs. To minimize rejection, doctors use donor tissue with MHC
molecules as similar as possible to the recipient, who will also take medicines that suppress immune
responses.
How do allergies occur? - Answers Allergies are exaggerated responses to antigens called allergens.
How does hay fever occur? - Answers Plasma cells secrete IgE antibodies specific to antigens on the
surface of pollen grains, causing hay fever. Next time pollen grains enter the body, they bind to the IgE
antibodies and induce mast cells to release histamine and other inflammatory chemicals.
How do autoimmune diseases occur? - Answers The immune system loses tolerance for self and turns
against certains molecules of the body. i.e.: lupus: the immunes system generates antibodies against
histones and DNA released by normal breakdown of body cells.
It can cause rashes, fever, arthritis, and kidney dysfunction.
Other autoimmune diseases: rheumatoid arthritis, type 1 diabetes.
How does HIV work? - Answers The virus HIV infects helper T cells. The virus persists in the host despite
an immune response due to its high mutation rate that promotes antigen variation. Over time,
untreated HIV avoids the adaptive immune response and abolishes it.
When does HIV become AIDS? - Answers When the helper T cell count drops and the HIV concentration
increases. Then it becomes a syndrome.
When can cancer increase? - Answers When adaptive immunity is inactivated
How can the immune system fight cancer? - Answers T cell therapy, Natural Killer Cell therapy, immuno-
oncology.
Can viruses cause cancer? - Answers Yes (15-20% of cancers involve viruses). HPV and hepatitis B are
examples of the 6 viruses identified that can cause cancer.
Differentiate sexual and asexual reproduction - Answers Sexual: creation of offspring by fusion of
haploid gametes to form diploid zygote
Asexual: creation of offspring without fusion of egg and sperm
What is parthenogenesis? - Answers The development of an egg into a diploid embryo without
fertilization
True or False: Plants, fungi, and bacteria have immune responses. - Answers True
How do immune cells recognize pathogens? What kind of recognition? - Answers Innate recognition and
Adaptive recognition.
What is the kind of immunity that all animals have and how does it work? - Answers 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? - Answers Adaptive immunity.
It's activated after the innate response and develops more slowly.
Give me an example of innate immunity and its steps. - Answers 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. - Answers The virus infects the host cell. An enzyme breaks up
the viral RNA so it won't replicate.
Give me 3 cellular innate defenses in mammals - Answers 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? - Answers 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? - Answers 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? - Answers 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? -
Answers T cells (mature in thymus) and B cells (mature in bone marrow)
Differentiate the primary and secondary immune responses involved in immunological memory. -
Answers Primary immune response is the first exposure to antigen, therefore slower. A clone of
lymphocytes is formed that are specific to the pathogen.
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. - Answers False. Instead, they mark pathogens for inactivation or
destruction.
What are the antibodies function? - Answers 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? - Answers 1) Genetic-code vaccines
2) Viral vector vaccines
3) Subunit vaccines
4) Weakened/inactive vaccines
How do the Pfizer and Moderna vaccines work? - Answers 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? - Answers 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? - Answers Cells transferred from one person to another, such as in
transplantation of tissues or organs. To minimize rejection, doctors use donor tissue with MHC
molecules as similar as possible to the recipient, who will also take medicines that suppress immune
responses.
How do allergies occur? - Answers Allergies are exaggerated responses to antigens called allergens.
How does hay fever occur? - Answers Plasma cells secrete IgE antibodies specific to antigens on the
surface of pollen grains, causing hay fever. Next time pollen grains enter the body, they bind to the IgE
antibodies and induce mast cells to release histamine and other inflammatory chemicals.
How do autoimmune diseases occur? - Answers The immune system loses tolerance for self and turns
against certains molecules of the body. i.e.: lupus: the immunes system generates antibodies against
histones and DNA released by normal breakdown of body cells.
It can cause rashes, fever, arthritis, and kidney dysfunction.
Other autoimmune diseases: rheumatoid arthritis, type 1 diabetes.
How does HIV work? - Answers The virus HIV infects helper T cells. The virus persists in the host despite
an immune response due to its high mutation rate that promotes antigen variation. Over time,
untreated HIV avoids the adaptive immune response and abolishes it.
When does HIV become AIDS? - Answers When the helper T cell count drops and the HIV concentration
increases. Then it becomes a syndrome.
When can cancer increase? - Answers When adaptive immunity is inactivated
How can the immune system fight cancer? - Answers T cell therapy, Natural Killer Cell therapy, immuno-
oncology.
Can viruses cause cancer? - Answers Yes (15-20% of cancers involve viruses). HPV and hepatitis B are
examples of the 6 viruses identified that can cause cancer.
Differentiate sexual and asexual reproduction - Answers Sexual: creation of offspring by fusion of
haploid gametes to form diploid zygote
Asexual: creation of offspring without fusion of egg and sperm
What is parthenogenesis? - Answers The development of an egg into a diploid embryo without
fertilization
