Immunology Midterm #1| 170 questions| with
complete solutions
Can normal skin microbiota be used for the treatment of some human skin related diseases such
as acne)? Correct Answer: - People have different microbiota in the skin, people with skin
conditions have different microbiota in their skin
- There are studies that have shown microbiota transfers from people with good skin to people
with acne which have been an effective treatment
___________ surfaces are covering the lining all our internal tubes Correct Answer: Mucosa
The epithetical that are part of the innate immunity have a thick _______ layer instead of a
_______ skin layer Correct Answer: mucosa, dead
______ cells have a high level of _____ content, so it well suited for the growth of beneficial
microbiomes Correct Answer: Mucosa, water
______ helps trap bad bacteria and prevent from them attaching to epithelium cells. It has
_______ to help fight any bad bacteria that does attach. Correct Answer: Mucin, glycosides
Epithelia cells of which layer renew very frequently and how this help our innate immunity
response? Correct Answer: Epithelial cells of the mucosa layer renew very frequently and this is
part of the innate immune system, because when many pathogens enter the body they need to
multiple and colonize, at the same time epithelial cells are being renewed at such a fast rate
which isn't a good host for these pathogens. So the turnover and shedding of epithelial are part of
the innate immune system.
The ____ layer of epithelial cells is covered with a high number and diversity of microbes,
except for in the ________ Correct Answer: mucosa, lungs
How does our microbiota help protect prevent infections? Correct Answer: 1. Microbiota fill
any viable space to keep any pathogens out
2. Microbiota learn to produce antibacterial viral components to kill pathogens. The microbiota
help by using their product peptides that help kill bad bacteria that colonize on the skin or other
organs
High concentration of _____ (bacteria) are found in our UG tract Correct Answer: LB
High concentration of _________ (bacteria) are found in the upper respiratory tract Correct
Answer: Gram positive
Studies have shown that germ-free (no microbiota) animals have _____________ immune
system. They were very to _________ infections and metabolic diseases. Correct Answer:
underdeveloped, susceptible
,Describe these 2 gut conditions and possible treatments for both of them (C.defficile and IBD)
Correct Answer: 1. C, Defficile: a cluster of bacteria in the gut that are antibacterial resistant,
antibiotics actually makes the condition worst by getting rid of good microbiota, the best
treatment is transplantation of healthy microbiota into the gut, it is an effective treatment as it
fills space in G.I tract and they create peptides which kills of C. defficile
2. IBD: Is another gut condition that can be treated with microbiota transplants. They found that
the microbiota of lean mice were different than those of fat mice. In one experiment when the
microbiota from a lean mice to transplanted to a obese mine they become lean, and this also
works vice versa.
Describe the importance of microbiota in the female reproductive tract: Correct Answer: -
Natural immunity in female reproductive system is important for prevent viruses like ZIKA virus
-The gut has a very diverse microbiota, but in the reproductive tract it's not a diverse at all, it's
mostly all one bacteria known as LB
-During pre-puberty and menopause the levels of LB are lower and the pH is higher. However,
during puberty the pH lowers and the LB concentration increase significantly
-We need low pH in the female reproductive tract (3.4 to 3.5) to prevent STI and thus subclinical
bacterial vaginosis occurs.
-LB produces low pH and antibacterial peptides to prevent bacterial vaginosis.
-Many viruses cannot bind receptors in a pH below 6, so an low pH in the vagina can protect us
from viruses
What is subclinical bacterial vaginosis? Correct Answer: When the female reproductive tract pH
is above this normal level
Why does the pH lower during reproductive age in the female reproductive tract? Correct
Answer: When there is surge of estrogen it causes the position of glycogen on epithelium cells
on the vagina to change and then LB feed on glycogen to produce lactic acid which lowers the
pH
What are the 3 types of antimicrobial substances produced by epithelial cells? Correct Answer:
1. Cryptidins and Alpha defensins: produced at the base of the small intestine crypsts
2. Beta-defensins: produced within skin and respiratory
3. Surfactant proteins A and D: present in lung and vaginal tract (function as opsonins which
enhance the efficiency of phagocytosis). They are very potent anti-microbial substances
What is the correlation between LB and bacterial vaginosis (BV)? Correct Answer: -In an
healthy human LB represents a large majority of their microbiota
-People with sub-clinical BV: have lower levels of LB
-People with BV: they do not produce lactic acid and have very little amounts of LB
Which age cohorts have been experiencing increased levels of STI? Correct Answer: STI is on a
rise in both elderly and youth
What is the best treatment for BV and other STIs? Correct Answer: Many scientist think to
prevent BV and STI is microbiota transplantation
, Does vaginal microbiota play any role in new born baby? How does the impact vary between
babies born naturally vs babies born via C-section? Correct Answer: -Babies a born through C-
sections have different vaginal and rectal microbiotas than naturally born babies
-Naturally born babies are being enriched with vaginal secretion enriched with LB while the
baby are in the mother's birth canal. In C-sections the babies are not exposed to this vaginal LB
-One clinical trial has revealed that rubbing a new born C section baby with vaginal secretion of
LB can help their microbiota diversity
Tears and saliva are natural ____________ as they have high ________ concentration Correct
Answer: disinfectant, lysozyme
How do lysosomes act on different types of gram-bacteria? Correct Answer: -Lysozyme are
effective in bacteria and gram-positive bacteria because these bacteria have a thick wall which
can be digest by lysozyme (this is why animals lick their wounds)
-Gram positive bacteria have a much thicker peptidoglycan than gram negative, and lysosome
digests peptidoglycan to break down the cell wall
Why are lysosomes more dangerous to gram-positive than gran-negative bacteria? Correct
Answer: Gran positive have a higher internal pressure (it is equal to propane gas), so if integrity
of peptidoglycan is compromised it can explode very easily
What is the complement system? Correct Answer: -When we encounter a pathogen one of the
first level of defensive that we have is a of soluble proteins made constitutively by the liver and
present in the blood, lymph, and extracellular fluids (these proteins are premade which work like
enzymes which are heat sensitive and are produced by the liver). -These plasma proteins are
collectively are known as the complement system or just complement.
-Complement coats the surface of bacteria and extracellular virus particles and makes them more
easily phagocytosed.
Describe the C3 cleavage? Correct Answer: When the complement system is activated by
infection it leads to the cleavage of C3 into a small C3a fragment and a large C3b fragment. C3b
is chemically reactive and becomes covalently attached, or fixed, to the pathogen's surface,
thereby marking the pathogen as dangerous. C3a is a component of the proteins are
inflammatory and potent chemoattracting proteins and potent recruiters of inflammatory cells to
the site of infection.
Describe the 3 pathways of the complement system: Correct Answer: 1. Alternative pathway:we
don't need specific receptors or antibodies, only the presence of any pathogen can activates the
complement system right away
2. Leptin: lectin can recognize sugars on the surface on bacteria, which leads to binding of
complement binding and activates the pathway
3. Classical pathway: We have to have antigen and antibody interaction to activate the pathway
What are the 3 main ways to achieve innate killing? What cells are used to carry out these 3
different ways? Correct Answer: 1. Phagocytosis:
complete solutions
Can normal skin microbiota be used for the treatment of some human skin related diseases such
as acne)? Correct Answer: - People have different microbiota in the skin, people with skin
conditions have different microbiota in their skin
- There are studies that have shown microbiota transfers from people with good skin to people
with acne which have been an effective treatment
___________ surfaces are covering the lining all our internal tubes Correct Answer: Mucosa
The epithetical that are part of the innate immunity have a thick _______ layer instead of a
_______ skin layer Correct Answer: mucosa, dead
______ cells have a high level of _____ content, so it well suited for the growth of beneficial
microbiomes Correct Answer: Mucosa, water
______ helps trap bad bacteria and prevent from them attaching to epithelium cells. It has
_______ to help fight any bad bacteria that does attach. Correct Answer: Mucin, glycosides
Epithelia cells of which layer renew very frequently and how this help our innate immunity
response? Correct Answer: Epithelial cells of the mucosa layer renew very frequently and this is
part of the innate immune system, because when many pathogens enter the body they need to
multiple and colonize, at the same time epithelial cells are being renewed at such a fast rate
which isn't a good host for these pathogens. So the turnover and shedding of epithelial are part of
the innate immune system.
The ____ layer of epithelial cells is covered with a high number and diversity of microbes,
except for in the ________ Correct Answer: mucosa, lungs
How does our microbiota help protect prevent infections? Correct Answer: 1. Microbiota fill
any viable space to keep any pathogens out
2. Microbiota learn to produce antibacterial viral components to kill pathogens. The microbiota
help by using their product peptides that help kill bad bacteria that colonize on the skin or other
organs
High concentration of _____ (bacteria) are found in our UG tract Correct Answer: LB
High concentration of _________ (bacteria) are found in the upper respiratory tract Correct
Answer: Gram positive
Studies have shown that germ-free (no microbiota) animals have _____________ immune
system. They were very to _________ infections and metabolic diseases. Correct Answer:
underdeveloped, susceptible
,Describe these 2 gut conditions and possible treatments for both of them (C.defficile and IBD)
Correct Answer: 1. C, Defficile: a cluster of bacteria in the gut that are antibacterial resistant,
antibiotics actually makes the condition worst by getting rid of good microbiota, the best
treatment is transplantation of healthy microbiota into the gut, it is an effective treatment as it
fills space in G.I tract and they create peptides which kills of C. defficile
2. IBD: Is another gut condition that can be treated with microbiota transplants. They found that
the microbiota of lean mice were different than those of fat mice. In one experiment when the
microbiota from a lean mice to transplanted to a obese mine they become lean, and this also
works vice versa.
Describe the importance of microbiota in the female reproductive tract: Correct Answer: -
Natural immunity in female reproductive system is important for prevent viruses like ZIKA virus
-The gut has a very diverse microbiota, but in the reproductive tract it's not a diverse at all, it's
mostly all one bacteria known as LB
-During pre-puberty and menopause the levels of LB are lower and the pH is higher. However,
during puberty the pH lowers and the LB concentration increase significantly
-We need low pH in the female reproductive tract (3.4 to 3.5) to prevent STI and thus subclinical
bacterial vaginosis occurs.
-LB produces low pH and antibacterial peptides to prevent bacterial vaginosis.
-Many viruses cannot bind receptors in a pH below 6, so an low pH in the vagina can protect us
from viruses
What is subclinical bacterial vaginosis? Correct Answer: When the female reproductive tract pH
is above this normal level
Why does the pH lower during reproductive age in the female reproductive tract? Correct
Answer: When there is surge of estrogen it causes the position of glycogen on epithelium cells
on the vagina to change and then LB feed on glycogen to produce lactic acid which lowers the
pH
What are the 3 types of antimicrobial substances produced by epithelial cells? Correct Answer:
1. Cryptidins and Alpha defensins: produced at the base of the small intestine crypsts
2. Beta-defensins: produced within skin and respiratory
3. Surfactant proteins A and D: present in lung and vaginal tract (function as opsonins which
enhance the efficiency of phagocytosis). They are very potent anti-microbial substances
What is the correlation between LB and bacterial vaginosis (BV)? Correct Answer: -In an
healthy human LB represents a large majority of their microbiota
-People with sub-clinical BV: have lower levels of LB
-People with BV: they do not produce lactic acid and have very little amounts of LB
Which age cohorts have been experiencing increased levels of STI? Correct Answer: STI is on a
rise in both elderly and youth
What is the best treatment for BV and other STIs? Correct Answer: Many scientist think to
prevent BV and STI is microbiota transplantation
, Does vaginal microbiota play any role in new born baby? How does the impact vary between
babies born naturally vs babies born via C-section? Correct Answer: -Babies a born through C-
sections have different vaginal and rectal microbiotas than naturally born babies
-Naturally born babies are being enriched with vaginal secretion enriched with LB while the
baby are in the mother's birth canal. In C-sections the babies are not exposed to this vaginal LB
-One clinical trial has revealed that rubbing a new born C section baby with vaginal secretion of
LB can help their microbiota diversity
Tears and saliva are natural ____________ as they have high ________ concentration Correct
Answer: disinfectant, lysozyme
How do lysosomes act on different types of gram-bacteria? Correct Answer: -Lysozyme are
effective in bacteria and gram-positive bacteria because these bacteria have a thick wall which
can be digest by lysozyme (this is why animals lick their wounds)
-Gram positive bacteria have a much thicker peptidoglycan than gram negative, and lysosome
digests peptidoglycan to break down the cell wall
Why are lysosomes more dangerous to gram-positive than gran-negative bacteria? Correct
Answer: Gran positive have a higher internal pressure (it is equal to propane gas), so if integrity
of peptidoglycan is compromised it can explode very easily
What is the complement system? Correct Answer: -When we encounter a pathogen one of the
first level of defensive that we have is a of soluble proteins made constitutively by the liver and
present in the blood, lymph, and extracellular fluids (these proteins are premade which work like
enzymes which are heat sensitive and are produced by the liver). -These plasma proteins are
collectively are known as the complement system or just complement.
-Complement coats the surface of bacteria and extracellular virus particles and makes them more
easily phagocytosed.
Describe the C3 cleavage? Correct Answer: When the complement system is activated by
infection it leads to the cleavage of C3 into a small C3a fragment and a large C3b fragment. C3b
is chemically reactive and becomes covalently attached, or fixed, to the pathogen's surface,
thereby marking the pathogen as dangerous. C3a is a component of the proteins are
inflammatory and potent chemoattracting proteins and potent recruiters of inflammatory cells to
the site of infection.
Describe the 3 pathways of the complement system: Correct Answer: 1. Alternative pathway:we
don't need specific receptors or antibodies, only the presence of any pathogen can activates the
complement system right away
2. Leptin: lectin can recognize sugars on the surface on bacteria, which leads to binding of
complement binding and activates the pathway
3. Classical pathway: We have to have antigen and antibody interaction to activate the pathway
What are the 3 main ways to achieve innate killing? What cells are used to carry out these 3
different ways? Correct Answer: 1. Phagocytosis:
