Exam 2

Question 1

According to the ‘Schesser’ definition, what are the three components of your metagenome?

Answer 1

1. Nuclear Genome
2. Mitochondrial Genome
3. Microbiome

Question 2

According to the ‘Schesser’ definition, how are each of the metagenome components inherited?

Answer 2

1. Nuclear Genome (inherited from BOTH parents)
2. Mitochondrial Genome (Inherited from your MOM)
3. Microbiome (started mostly from Mom, but eventually from your environment)

Question 3

What is a germline cell?

Answer 3

Passes on diseases

Question 4

What is a somatic cell?

Answer 4

cells that are NOT donated to future generations

Question 5

What category would an antibody producing B cell be in?

Answer 5

Germline (antibodies are passed down from the mother through passive immunity)

Question 6

What is a ‘single-nucleotide polymorphism’ (or ‘SNP’)?

Answer 6

SNPs are certain points in the genome where the nucleotides are different

Question 7

How can SNPs be used to determine family relationships (e.g., ‘23 and me’)

Answer 7

Can help determine the amount of DNA shared/ gene activity in relation to other individuals; the more commonality, the closer the relation

Question 8

What is the main evidence that mitochondria evolved from free-living bacteria?

Answer 8

Mitochondria have their own cell membranes and DNA genome separate from the “parent” cell

Question 9

What is a pathogen?

Answer 9

A bacterium, virus, or other microorganisms that can cause disease//
opportunistic pathogens cause acute infections

Question 10

What is a pathobiont?

Answer 10

Organisms associated with chronic inflammatory conditions

Question 11

How does the pathogen Vibrio cholera cause the disease cholera?

Answer 11

the pathogen VC causes cholera by expressing a structure on the surface of itself and grabbing onto the cells of the intestine; once attached, VC starts to secrete a toxin into the intestine

Our intestinal cells then take up the toxin, which fools our gut to become saltier, and this leads to all the symptoms of cholera: water rushing out, extreme dehydration, and explosive diarrhea.

Question 12

How does the pathogen vibrio cholera differ from salmonella enterica in terms of how damage to our intestinal tract?

Answer 12

The difference between the two is that vibrio stays in the gut while salmonella stays on the intestinal tract and infects the deeper intestinal tissue

Question 13

What are two ways we can be harmed by staphylococcus?

Answer 13

Think of staph as a “generalist”; it can infect skin and soft tissues, the bloodstream, bone, or joints. It can lead to pnuemonia, bloodstream infections, or boils on the skin.

Question 14

In individuals with cystic fibrosis, why do they always experience fatal infections caused by Pseudomonas aeruginosa?

Answer 14

Pseudomonas genetically morphs through the individuals life, once it has the ability to create a biofilm, that’s when the individuals’ survival rate decreases dramatically. The individual will either have to await death or undergo a risky lung transplant.

Question 15

Describe the 4 stages of pregnancy and name a key event in each

Answer 15

1- Fertilization: the union of a female egg and a male sperm

2- Implantation: the developing embryo attached to the uterine wall

3- Placentation: growth of the placenta inside uterus

4- Parturition: childbirth

Question 16

Are the immune systems of pregnant women suppressed?

Answer 16

NO

Question 17

What types of immune cells are present in the human placenta?

Answer 17

Natural Killer (NK) cells are the most abundant; there are also macrophages and certain T cells

Question 18

Why is listeria monocytogenes a threat to pregnant women?

Answer 18

This bacterial pathogen can infect the placenta and cross the placental barrier and infect the fetus; can cross the blood-brain barrier; can cross the intestine, get into our gut, infect the liver and cause a miscarriage if the immune system over-reacts

Question 19

What types of factors contribute to autoimmune diseases?

Answer 19

Genetic predisposition & environment

Details: for genetic predisposition, this does not mean you will for sure have the disease expressed, but environmental conditions could contribute to disease expression.

Example: overexposure to the sun that damages the DNA that can cause inflammation and can make manifestation of the disease that much worse.

Question 20

What are the differences between systemic and organ-specific autoimmune diseases? Give an example of each.

Answer 20

Systemic- engages multiple organs (lupus)

Organ-specific: affects particular targets in the body (Type 1 Diabetes= pancreas)

Question 21

What are different molecular mechanisms of autoimmune diseases?

Answer 21

Protein modification events (phosphorylation of proteins that is facilitated by the response to microbes sensed by the immune system)

Molecular mimicry- when microbes make proteins that resemble our own so when the immune system goes to attack, it attacks both the microbes and self.

Immune response pathways- (B&T cell activation; innate and adaptive immune systems)

Question 22

What is molecular mimicry?

Answer 22

A mechanism when microbes create proteins that are similar looking to our own, so when the immune system goes to attack, it attacks both the microbes and self.

MM can happen on purpose or by chance. There are certain structures that are versatile and can adapt their functionality and if the structure takes on a certain form, it can look similarly to the surrounding structures. Some organisms do this on purpose and use MM to escape detection from the immune system.

Question 23

How does MM cause autoimmune disease rheumatic fever?

Answer 23

Rheumatic fever is an autoimmune reaction to strep bacteria. If the strep bacteria looks similar to structures in the body, the immune system can be fooled by molecular mimicry and this error can lead to a misguided response to the strep bacteria.

Question 24

What is the mechanism of Myasthenia Gravis?

Answer 24

MG is caused when the receptor for muscle cell movement is blocked by autoantibodies and the individual is no longer in control of their muscular movements.

Question 25

TLR7 mutations cause human lupus and demonstrates that changes in one gene can cause autoimmune disease. Elaborate on this more:

Answer 25

At the fundamental level, an autoimmune disease is the manifestation of an aggressive response to any deviation from “normal”. If the immune system recognizes a single gene that is off, it can be triggered to respond inappropriately and this overreaction can override its recognition of self from non self.

Question 26

What is the normal function of IgE?

Answer 26

Mediation of killing of parasites

Question 27

Describe the sequence of events leading to the allergic reaction “immediate hypersensitivity”.

Answer 27

1. Activation of allergen specific B&T cells
2. IgE secretion by allergen specific B cells
3. IgE binds to IgE receptor on mast cells
4. upon second exposure to allergen, the allergen will engage with the mast cell and the mast cell will release all of its contents
5. Degranulation causes the immediate hypersensitivity or analphylaxsis

Question 28

What are PID?

Answer 28

Primary immunodeficiency disorders:

They weaken the immune system, which causes more health problems to occur more easily.

How? Individuals are either born missing some of the body’s immune defenses or born with an immune system that doesn’t function properly

Question 29

PID

Answer 29

Primary immunodeficiency Disorders:

Combination of the absence of B and T cells (the WORST)

Having predominantly B cells

T cell Immunodeficiency that can affect the production of B cells

Question 30

What is the difference between XLA and hyper IgM syndromes.

Answer 30

XLA has no B cells

IgM- decreased blood levels of Immunoglobin G and normal or increased levels of Immunoglobin M & individual can no longer produce antibodies