GN 301 Exam 3 Review Questions

Be able to identify some characteristics that are under polygenic (as opposed to single gene) control.

Polygenic: Height, skin color, eye color, IQ, weight, hair color, schizophrenia

Single gene: sickle cell anemia, galactosemia, ABO blood type

What are some characteristics of multifactorial/polygenic traits?

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* Many genes control the trait
* The effect of each gene is small
* Effects of the genes add together 
* The environment also influences the phenotype
* Although there is a discrete underlying genotypic distribution, the phenotypic distribution is continuous and approaches a normal statistical distribution

Describe the difference between monozygotic and dizygotic twins.

Monozygotic: identical, one egg splits into two, 100% identical DNA

Dizygotic: fraternal, two eggs, 50% identical DNA like siblings

What are “Super Twins”?

having a combination of identical and fraternal twins in one pregnancy

Which type of twinning is more likely to run in families? Why?

There is evidence that fraternal twinning is inherited. There are differences in fraternal twin rates in different geographical regions and among different racial groups. The frequency also increases with an increase in maternal age. 

Define heritability, concordance, concordant, discordant, correlation

Heritability: the proportion of phenotypic variance that is due to genetic effects (H^2 = V_G / V_P) (variance in genotype / phenotype)

Concordance: the probability that a pair of individuals will both have a certain characteristic given that one of the pair has the characteristic

Concordant: if twins same for a trait

Discordant: if twins differ for a trait

Correlation: the proportion of variance that two traits share due to genetic causes, the correlation between the genetic influences on a trait and the genetic influences on a different trait estimating the degree of pleiotropy or causal overlap

V_P = V_G + V_E

Be able to compare values of MZ:DZ concordance ratios to determine which trait has a higher heritability

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* If the MZ and DZ values are similar, most of the variation in phenotype is due to variance in environmental effects which indicates a @@low heritability.@@ 
* If there is a low MZ value but it is still quite higher than the DZ value, there is a genetic predisposition, but a @@low to moderate heritability@@ for the trait. 
* High MZ: Low DZ indicates significant role of the variance of genetic effects in the @@phenotypic variance@@
* Similar MZ and DZ indicates a lot of variation is due to variance in @@environmental effects@@
* Low MZ but still much higher than DZ indicates @@genetic predisposition@@, but variance due to @@environmental factors@@ is important in the variance of the phenotypes for this trait

What is a threshold trait?

A threshold trait refers to a trait that only becomes apparent when a certain threshold of intensity is reached.

Use the idea of the additive effects of alleles to determine whether an individual of a particular genotype has a genetic disorder

In these situations, risk factors accumulate based on the genotype and the environment. If the risk factors exceed a threshold, the disorder is seen.

Which trait is expected to have a higher heritability based on the MZ:DZ ratios given? Trait A 95:85 or Trait B 95:4

@@Trait B@@

High MZ: Low DZ indicates significant role of the variance of genetic effects in the phenotypic variance

The expression of quantitative characteristics depends on the genotype and ______

the environment

How are twin studies used to help us understand the heritability of quantitative characteristics?

Twin studies are studies conducted on identical or fraternal twins. They aim to reveal the importance of environmental and genetic influences for traits, phenotypes, and disorders.

In order to evaluate the genetic contribution of a characteristic, is it best to compare which of the following 2 types of twins?

* MZ reared together, MZ reared apart, DZ reared together, DZ reared apart

Compare MZ raised __together__ and DZ raised __together__ to estimate genetic effects

Which 2 (of the above) should be compared to evaluate the environmental contribution to a trait?

Compare MZ raised __together__ and DZ raised __apart__ to estimate genetic effects

What do the abbreviations QTL and GWAS stand for?

QTL stands for __Quantitative Trait Loci__

GWAS stands for __Genome Wide Association Studies__

What is the purpose of a GWAS experiment?

Allow us to identify genes that are associated with quantitative traits.

The average IQ value (based on IQ tests) is set at _____

100

What are some genetic causes of intellectual disability?

Single gene examples (Simple Mendelian)

* PKU (autosomal recessive)
* Galactosemia  (autosomal recessive)
* Hurler Syndrome (autosomal recessive)
* Tay-Sachs Disease (autosomal recessive)
* Rett Syndrome (X-linked dominant)

Polygenic: Possible to get the “bad luck” alleles of several polygenes that contribute to intelligence

* See familial inheritance patterns of some intellectual disabilities
* More than 75% of cases come from less than 10% of families
* If both parents have IQ values in the 50 – 70 range, there is a 60-70% chance that their child will also have a subnormal intelligence

Approximately ____% of the US population is intellectually disabled.

3

What is the genetic basis of each of the following disorders? Down Syndrome, Rett Syndrome, Fragile X Syndrome, Williams Syndrome, Patau Syndrome, Edward Syndrome, Galactosemia, PKU, Hurler Syndrome, Tay Sachs

* Down Syndrome: trisomy 21
* Rett Syndrome: X-linked dominant
* Fragile X Syndrome: X-linked dominant
* Williams Syndrome: autosomal dominant
* Patau Syndrome: trisomy 13
* Edward Syndrome: trisomy 18


* Galactosemia: autosomal recessive
* PKU: autosomal recessive
* Hurler Syndrome: autosomal recessive
* Tay Sachs: autosomal recessive

Intellectual disabilities can have several causes: Give the name of a genetic disorder that causes intellectual disabilities and is inherited in each of the manners below: Trisomic, autosomal recessive, X linked, Deletion

Trisomic: Down Syndrome, Patau Syndrome, Edward Syndrome

Autosomal recessive: Galactosemia, PKU, Hurler Syndrome, Tay Sachs

X-linked: Fragile X Syndrome (dominant), colorblindness

Deletion: Cri du chat, Wolf-Hirschhorn, Angelman Syndrome

Angelman Syndrome is usually due to a…

Deletion of part of chromosome # 15 including the UBE3A gene

Cri du chat is…

Usually a de novo (sporatic) event

How is Down syndrome usually diagnosed in children?

Karyotype

This disorder is sometimes referred to as the "Happy Puppet" syndrome

Angelman Syndrome

In order to be considered to be intellectually disabled, an individual’s IQ is less than ______.

70

What are some environmental factors that can lead to intellectual disabilities?

* **Prenatal: pre-birth health conditions**
* Infections (measles, malaria, HIV, herpes)
* Small enough to get to fetus through placenta
* Medicines, Drugs, Alcohol, Smoking
* Maternal Health
* High Blood Pressure 
* Diabetes 
* Nutrition
* **Perinatal: at delivery**
* oxygen deprivation at delivery is the main cause from environmental factors
* Premature delivery (low birth weight) (

Define Perinatal.

at delivery

What is the difference between Premature and Preterm?

"Preterm" refers to a baby born before the end of the 37th week of pregnancy. This means that the baby is born before completing a full term of pregnancy, which is typically 40 weeks.

"Premature" refers to a baby born before the 37th week of pregnancy, but it also takes into account the baby's weight at birth. A premature baby is one who is born before completing a full term of pregnancy and weighs less than 5 pounds, 8 ounces (2,500 grams) at birth.

Distinguish between mental illness and intellectual disabilities.

Mental illness refers to a wide range of mental health conditions that affect a person's mood, thinking, and behavior, while intellectual disabilities are a type of neurodevelopmental disorder that causes limitations in intellectual functioning and adaptive behavior.

Approximately 1 in ____ people will be hospitalized for mental illness.

10

Approximately ____% of hospital beds are occupied by the mentally ill.

50

Be able to answer questions/discuss the types, symptoms, and genetics of mental and behavioral disorders mentioned in class (at the level discussed in the lecture) including narcolepsy, addiction, alcoholism, bi-polar disorder, schizophrenia, eating disorders, autism, Huntington’s Disease, Parkinson Disease, Epilepsy, Alzheimer Disease

* narcolepsy: Individuals with narcolepsy can suddenly fall into a short, but deep sleep.
* addiction: a compulsive physiological and psychological need for a habit forming substance
* alcoholism: addiction to alcohol; an important role of genetics in alcoholism (how well the body detoxifies alcohol, how well individual handles craving feelings). Abuse of alcohol can cause degeneration of brain and nerve cells, Alcoholics are often placed in hospitals for their addiction and to help them safely withdraw from over-use of alcohol.
* bi-polar disorder: characterized by behavior patterns that span a broad range. Individuals may sometime act very introverted and other times may have loud outbursts. Individuals have a range of emotions with extremes such as severe depression, feelings of hopelessness and suicidal thoughts. On the other side of the spectrum, individuals may have strong feelings of euphoria and well-being. 40% of first degree relatives (parents, sibs, children) also affected.
* schizophrenia: 10% genes shared with various relatives. Individuals with schizophrenia have an altered perception of reality. They often have difficulty organizing thoughts and speech and can suffer delusions and hallucinations. They often do not express emotion as readily. This can lead to social isolation, which in turn can lead to intellectual deterioration. Many schizophrenics report hearing voices that tell them to do destructive things. Symptoms onset ages 18-33.
* eating disorders: type of addiction that includes binge eating and starving. Levels of serotonin are related to eating disorders Low serotonin leads to depression. Binge eating increases serotonin level and leads to feeling of well-being. High serotonin leads to feelings of anxiety. Starving self lowers serotonin to give a calming effect
* autism: Individuals with autism are characterized by difficulties with social interaction and the ability to communicate. Some have a tendency to engage in repetitive behaviors.
* Huntington’s Disease: An inherited condition in which nerve cells in the brain break down over time.
* Parkinson Disease: Individuals with Parkinson’s Disease have a clear mind but gradually lose control over muscles. 
* Epilepsy: A disorder in which nerve cell activity in the brain is disturbed, causing seizures.
* Alzheimer Disease:
*  Alzheimer’s patients suffer from a progressive loss of memory, motor activity and the ability to recognize even the closest relatives and loved ones, and as body systems can no longer function, eventual death. 6th leading cause of death in USA.

What is the difference between a nerve cell and a neuroglia cell? Which does a typical person have more of? Which is the type of cell that can develop into brain tumors?

Nerve cells, also called neurons, are specialized cells in the nervous system that transmit electrical and chemical signals between the brain, spinal cord, and the rest of the body. Neuroglia cells, also called glial cells, provide support and protection for neurons and help maintain the overall health of the nervous system.

A typical person has @@more neuroglia@@ cells than nerve cells, with a ratio of about 10:1.

@@The type of cell that can develop into brain tumors are neuroglia cells.@@Unlike neurons, neuroglia cells can divide and multiply throughout life, increasing the risk of mutations and the development of tumors.

What is the purpose of a neuroglia cell?

The neuroglia cells guide development and movement of the neurons in the developing embryo. They produce growth factors throughout your life and they can divide. There are around 1 trillion of them.

Nerve cells communicate with each other across spaces called __________.

synapses

List the 4 levels of genetic control involved in communication between 2 nerve cells.

1. Production of the myelin sheath


2. Synthesis of neutrotransmitter


3. Transporter protein in sending cell
4. Receptor protein in receiving cell

Define neurotransmission

the process by which nerve cells, or neurons, communicate with each other through the release and reception of chemical messengers called neurotransmitters.

Describe the roles of neurotransmitters such as norepinephrine, serotonin and dopamine at the levels discussed in class.

Norepinephrine is a neurotransmitter involved in the "fight or flight" response, which helps to prepare the body to deal with stress. It increases heart rate, blood pressure, and respiration, and helps to mobilize energy stores.

Serotonin is a neurotransmitter involved in regulating mood, appetite, and sleep. It is often associated with feelings of well-being and happiness. Imbalances in serotonin levels have been linked to depression and anxiety.

Dopamine is a neurotransmitter involved in regulating movement, motivation, and reward. It helps to control the brain's pleasure and reward centers and is involved in reinforcing behaviors that are necessary for survival. Imbalances in dopamine levels have been linked to conditions such as Parkinson's disease, schizophrenia, and addiction.

Define Population

local group of a species among which successful mating occurs and viable offspring are produced

State the Hardy-Weinberg Equilibrium Law

* State Law: After one generation of mating, allele frequencies will remain at equilibrium

What genotypic frequencies are expected if a population is consistent with Hardy-Weinberg equilibrium frequencies?

for population that has gametic array of pA + qa, the genotypic array at equilibrium will be p^2 AA + 2pq Aa + q^2 aa

List the conditions required for Hardy-Weinberg equilibrium

* Migration does not occur,
* the population is infinitely large,
* mutation does not occur,
* the population is panmictic,
* and selection does not occur

Be able to calculate allele and genotype frequencies from population data

USE:

Frequencies at equilibrium: for population that has gametic array of pA + qa, the genotypic array at equilibrium will be p^2 AA + 2pq Aa + q^2 aa

NOTE: p + q = 1 and p^2 + 2pq + q^2 = 1 ALWAYS!

Define Evolution.

changes in the genetic composition of a population including the emergence of species, divergence of species and extinction of species, over a long period of time

What is the source of new alleles?

mutation

What is the effect of migration on the diversity within and between populations?

Migration is the movement of individuals from one population to another. Assuming that the frequencies of the immigrants differ from that in the recipient population, this decreases diversity between the two populations and increases diversity within the recipient population.

What are the 3 types of selection and what changes are brought about in a population with each type of selection?

* **Directional:** 
* favors one extreme or the other. 
* Population mean increases or decreases depending on which extreme is favored.


* **Disruptive:**
* Advantage for both extremes. Heterozygote least fit.
* Leads toward bimodal population


* **Stabilizing:**
* Heterozygotes favored
* Decreases variance
* Leads to polymorphisms (both alleles remain in population)

The type of selection in which both homozygous types are favored over the heterozygous type is called

disruptive

The type of selection that favors heterozygous individuals over homozygous individuals is called

Stabilizing Selection

The type of selection that favors one homozygous type and is least favorable for the other homozygous type is

directional

Give examples of selection in human populations

Sickle Cell and Malaria: an example of stabilizing selection

Discuss the effects of selection in humans with regards to sickle cell anemia, cystic fibrosis, lactase production, and high altitude

* Sickle Cell and Malaria: an example of __stabilizing__ selection
* Cystic Fibrosis: unclear reason why so many Europeans have the allele since it doesn’t protect them against any diseases (like Cholera and Typhoid)


* Lactose Tolerance: Selection for tolerance as dairy products introduced into diet (advantage to be able to use as nutrition source)
* Tolerance to high altitude: Tibetans’ bodies have adapted to low oxygen concentration in high altitudes

What is the effect of consanguineous matings on genotypic frequencies in a population?

* Decreases the proportion of heterozygous individuals in the population
* Increases the proportion of homozygous genotypes
* Increases the frequency of recessive phenotypes

Define inbreeding

 mating of related individuals changes frequency of genotypes, but not allele frequency. Leads to more homozygous individuals in population over time. Affects all loci in the organism.

Define Positive and Negative Assortative Mating. Which is more similar to inbreeding?

* **Positive assortative mating:** mating like individuals together, results in similar situations as @@inbreeding@@ (increased homozygotes) but only for loci in mate selection
* **Negative assortative mating**: “opposites attract” would keep diversity in the population and tends to increase the frequency of heterozygous individuals for the loci in mate selection

Define: Genetic Drift, Founder Effect, Bottleneck and describe their effects on allele and genotypic frequencies

**Genetic drift:** the random variation in gene frequency from generation to generation due to small population size and sampling error

**Founder effect**: A founder population occurs when a small group of individuals from one population leaves the big population and colonizes a new area.

**Bottleneck:** occurs when the population size decreases dramatically due to some type of disaster.

What types of DNA sequences are typically evaluated to determine evolutionary relationships?

Mitochondrial DNA and the Y chromosome

What type of chromosome aberration separates human and chimpanzee chromosomes? (Think about how many chromosomes we have and how many chimps have)

Human and chimpanzee chromosomes differ due to a fusion event in human chromosome 2. Humans have 23 pairs of chromosomes, while chimpanzees have 24 pairs. It is believed that in the common ancestor of humans and chimpanzees, two ancestral chromosomes fused end-to-end to form human chromosome 2. This is evidenced by the presence of telomere and centromere sequences in the middle of human chromosome 2, which are normally found at the ends of chromosomes. Therefore, the chromosome aberration that separates human and chimpanzee chromosomes is a fusion event.

A _______ tree show genetic relationships between species

Phylogenetic

A population of GN 301 students was scored for the MN blood type locus and a genotypic array of 0.35MM + 0.42 MN + 0.23 NN was obtained. Calculate the frequency of the M and N alleles in the population.

f(M) = 0.56

f(N) = 0.44

A population of parakeets was scored for feather color. Results are tabulated below.

Phenotype (Genotype) Blue (BB) Green (Bb) Yellow (bb)

Number Observed": 25 120 55

a. Determine the gametic and genotypic arrays for this population

b. If this population was allowed to mate at random (assuming all other conditions for HWE are met), what is the expected genotypic array in the progeny? (Hint: The population will be at HWE equilibrium frequencies in the progeny under these conditions)

a. Gametic: 0.425 B + 0.575 b

Genotypic: 0.125 BB + 0.6 Bb + 0.275 bb

b. 0.1806 BB + 0.4888 Bb + 0.3306 bb

Galactosemia is an autosomal recessive disorder. Galactosemia occurs in approximately 1 in 53,000 births in the US. For the purpose of this question, assume that the population satisfies HWE conditions.

a. What is the frequency of the galactosemia allele (g)?

b. What is the frequency of carriers (Gg individuals)?

a. f(g) = 0.0043

b. f(Gg) = 0.0086

Who can be the father of this child?

Mom is blood type B. Baby is blood type A. John is type AB, Harry is type O, and Sam is type B. What is the genotype of the mother in this problem?

Mom: BO (can’t be BB)

Baby: AO (can’t be AA)

Dad: must be Type A: AA or AO. Can’t be Type B or Type O.

A B

B AB BB

O AO BO

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So the father must be John (AB) and the mother’s genotype is BO.

Define: Antigen, Antibody

**Define: Antibody**

* Made in response to the entry of a foreign protein
* Coded for by genes

**Define: Antigen**

* Substance that stimulates production of an antibody
* Seen as “foreign”

The A and B proteins that are on the blood cells are _____

antigens

Which blood type is the Universal Donor? The Universal Recipient?

Universal Donor: Type O-

Universal Recipient: AB+

Who can donate to Jane if Jane is Type A+?

Jane: A_ R_

Donors: Type A+, Type O+

Which of these loci contain multiple alleles? ABO Locus, HLA Locus, Rh Locus, Beta chain of Hemoglobin

The ABO Locus, HLA Locus, and Rh Locus contain multiple alleles, while the Beta chain of Hemoglobin has only two alleles.

What is RhoGAM? Who is it given to and under what conditions is it required?

**RhoGAM:** concentrated Rh+ antibodies. 

* RhoGAM is given to __Rh- mom within 72 hours after delivering an Rh+ baby, even if its a miscarriage, so her antibodies don’t attack the next baby__

What does RhoGAM do?

RhoGAM works by binding to Rh-positive red blood cells in the mother's blood, preventing her immune system from recognizing them as foreign and producing antibodies against them

What does HLA stand for? Describe a situation when the alleles at the HLA loci are important medically.

HLA Loci stands for __Human Leukocyte Antigen__

They are important in organ transplants.

* Greater transplant success if match at HLA loci
* Very unlikely that 2 unrelated people match at all 6 of these genes 
* Assuming 20 alleles per locus each locus has (20/2)(20+1) = 210 possible genotypes
* Since there are 6 loci, we have (210)6 = 8.6 x 1013 possible combinations possible
* Immunosuppressant drugs to help prevent rejection
* “Strip” tissues of antigens to help prevent rejection

Define: autograft, isograft, allograft, xenograft, haplotype

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* Autograft: you donate an organ (most often skin) to yourself on another part of your body
* Allograft: a transplant from one person to another, who are not related
* Isograft: a transplant between identical twins
* Xenograft: a transplant from an entirely different species

What is organ trafficking? Discuss ethical issues associated with organ trafficking.

**Organ trafficking** refers to the illegal trade of organs for transplantation. It involves the removal of organs from living or deceased donors and the sale of those organs to recipients or their agents, often with the involvement of intermediaries and organized crime syndicates.

The ethical issues associated with organ trafficking are numerous. Firstly, exploits the vulnerable populations, such as the poor and marginalized, who may be coerced or deceived into selling their organs. Additionally, organ trafficking creates a market for human body parts, which commodifies the human body and reduces it to a mere object for sale.

What is transplant tourism? Discuss ethical issues involved with transplant tourism.

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* Transplant Tourism is when someone goes to another country to receive an organ illegally (that is outside the laws of that country). It is okay to go to another country to get medical care within the law. 
* One of the problems with donating is that there is a recovery period and even after recovery, the donor may not be as capable of doing heavy manual work, so these men have money from selling their kidney for a while but may be less able to work in the future.

What is the purpose of T cells? Where are they formed?

The T cells originate in the @@bone marrow@@ and then move to the thymus where they mature. They are responsible for cell mediated immunity, or recognizing and destroying invading cells.

What is the purpose of B cells? Where are they formed?

The B cells originate in the @@bone marrow.@@ They mature and are released from the lymph nodes and spleen. These cells secrete antibodies, which in turn can attack foreign agents in the body.

How does our body produce such a large number of different antibodies with a relatively small number of different genes? What unusual situation at the DNA level helps provide this variation?

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* **Somatic Recombination:** parts of the DNA are removed and the remaining parts are joined together. Each protein chain in the antibody has a constant region, a joining region and a variable region. 
* **Junctional Diversity:** Pre-mRNA is processed causing additional segments to be removed
* High frequency of **Somatic Mutations**: (\~2%) in the variable region of the DNA is also common

What is wrong in individuals with the following disorders? Diabetes (both types), Bruton’s Disease, SCID

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* Type 1 Diabetes:
* T cell mediated autoimmune attack. Attacks cells in the pancreas that normally make insulin. Need insulin in order to metabolize glucose and regulate blood sugar levels.
* Type 2 Diabetes:
* The pancreas makes less insulin than used to, and your body becomes resistant to insulin.
* Bruton’s Disease: 
* X-linked
* T cells, but no B cells so no antibodies
* SCID
* “Bubble boy”
* Missing T and B cells
* 1 type is missing adenosine deaminase enzyme
* Gene therapy for ADA-deficient SCID patients

What disorder did David (the Bubble Boy) have?

SCID

Describe the characteristics that a cell must have to be classified as a stem cell

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1. They have the ability to divide and make more stem cells like themselves in the tissue they are from and  they have to be able to divide immortally in culture.
2. Although it varies from cell type to cell type, non-stem cells only divide about 50 times in culture prior to death. Many cell types cannot even divide that many times in culture. 
3. Finally, stem cells can differentiate into specialized tissues in the body. Different types of cells can differentiate into different tissues. 

What are some goals of stem cell research? What do scientists hope to be able to do some day?

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* Knowledge about processes of development and differentiation may allow us to learn how heart disease, cancer, birth defects, etc develop and may help us to better treat or prevent these.
* Therapy: Manipulation of stem cells into specific cell types may allow physicians to repair and/or regenerate damaged tissues and organs 
* Drug Testing: Recreate disease in cell line and test different drugs

Distinguish between adult and embryonic stem cells. How is each type obtained?

**How to get adult stem cells?**

* Umbilical cord at delivery
* Bone Marrow of adult
* Some adult cells (brain, liver, skeletal muscle, dermal tissues, others)
* Amniotic fluid (surrounding fetus during pregnancy)

**How to get embryonic stem cells?**

* From blastocyst of early embryo
* E.g. embryos created for in vitro fertilization, but not used/needed for that purpose
* Inner cell mass = ESCs
* Implant DNA of somatic cell into an enucleated human egg

What is somatic cell nuclear transfer? Describe the procedure

\
* Another way that embryonic stem cells can be obtained is through Somatic Cell nuclear transfer, which is also called Therapeutic cloning. 
* This process uses a patients’ cells so the stem cells derived from it should be compatible with the patient. A donor egg is obtained, and the nucleus is removed from this egg creating an enucleated egg. A somatic cell is obtained from the patient. The nucleus is removed from the patient’s cell.
* The nucleus from the patient’s cell is inserted into the enucleated egg cell. The resulting embryo is allowed to develop until the blastocyst stage. Then the inner cell mass is harvested and cultured. These cells can then be treated with various growth factors to stimulate differentiation into a variety of cell types.

What is meant by totipotent, multipotent, pluripotent? Which term is appropriate in describing adult stem cells? Which is appropriate for embryonic stem cells?

**Embryonic v Adult:** Embryonic cells have potential to differentiate into many/most @@(Pluripotent@@ not Totipotent) tissue types. Adult cells are more limited as to types of tissues they can become (@@multipotent@@). 

**Pluripotent v Multipotent**: Pluripotent cells (Embryonic) can form any body tissue except placenta. Multipontent (Adult) have less tissues they can become.

A @@**totipotent**@@ **cell** can form any body tissue including placenta. We do not have stem cells that are totipotent

Name the researchers who received a Nobel Prize in 2012 for their work on stem cells and regeneration biology. Discuss the contributions each made to this field.

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* Gurdon: (1962) Discovered that a specialized cell possessed all the genetic information needed to develop all cells in a mature organism
* Yamanaka: (2006) Determined that the insertion of 4 genes could reprogram differentiated cells and cause them to become pluripotent stem cells

Discuss some of the controversial/ethical issues regarding stem cell research. What types of stem cells do these issues refer to?

CONTROVERY AROUND EMBRYONIC STEM CELLS

* Many people are strongly opposed to the destruction of embryos because of their potential for human life. Even when the purpose for that embryo is to save another life. 
* Some others propose that ethical judgments and valuations of an embryo should be based not on the possibility of life, but on the probability of life. Meaning that, if an embryo is not likely to survive anyway, it could be more morally acceptable for it to be used for scientific purposes. This argument could justify using stem cells from aborted fetuses and embryos incapable of implantation in IVF for morphological reasons. 
* Still other people are fine with the idea of using embryos of any kind or viability to develop treatments like therapeutic cloning.
* Also controversy with donor exploitation. Lots of eggs could be needed, and poorer women would be more likely to donate eggs for financial gain. There are health risks from surgical removal and hormonal treatments used to extra oocytes.

Discuss the historical and current state of federal regulations on stem cell research.

* For adult stem cell research?
* Federal funding is available for adult stem cell and iPS research


* For embryonic stem cell research?
* Some states ban embryonic stem cell research and/or state funding for such research
* History and Scientific Problems with restrictions


* The history of federal funding and restrictions for the use of federal funds has been complex. First, Federal funds are available for adult stem cell research and for IPS research The controversy has to do with embryonic stem cells. In 2001, President George W Bush issued an executive order that allowed federal funding for embryonic stem cell research on cell lines developed prior to August 9, 2001, but not on more newly developed embryonic stem cell lines.

Which organization set the current regulations for ESC funding? What are some of the new regulations?

* Current Status and Role of NIH
* NIH published guidelines in July, 2009. One important guideline was that new embryonic stem cell lines had to be registered on the NIH site and then approved for use before funding could be received for research using those lines. 
* Another important guideline was that excess embryos from fertility clinics could be registered for use if there was informed consent obtained from the embryo’s owners, and if there was no financial incentive for allowing the embryos to be used.
* The approval process went quickly – for something in the government – and the first new embryonic stem cell lines were approved for funding in December 2009. This is still the policy for new embryonic stem cell line research funding in the United States.

Does NC allow embryonic stem cell research? Adult stem cell research?

North Carolina has not banned embryonic stem cell research, but it does not provide state funding for such research. Adult stem cell research is allowed in North Carolina and is not restricted by state law. However, researchers using adult stem cells must comply with federal regulations, which restrict the use of federal funds for research on embryonic stem cells.

What are the 4 main types of cancer. Be able to distinguish between them and give an example of each (The 4 types are Sarcoma, Carcinoma, Lymphoma, Leukemia)

* Leukemia:
* Abnormally large number of leukocytes (WBCs) made by bone marrow
* Common in children. Can occur in adults
* 3.4% of cancers


* Lymphoma: 
* Abnormally large number of lymphocytes (type of WBC) made by spleen and lymph nodes
* E.g. Hodgkin Disease
* 5.4% of cancers


* Carcinoma:
* Solid tumor from epithelial tissue
* Body surface coverings and derivatives 
* E.g. skin, breast, respiratory, colon, urinary
* 85.3% of cancers


* Sarcoma
* Solid tumors from embryonic mesoderm tissue
* E.g. bone, cartilage, muscle, fat
* 1.9% of cancers


* Others/Mixed Tissue
* From mixed tissues eg. Testicular and ovarian cancers
* 4% of cancers

What is clonal evolution and why is it important in cancer?

Clonal evolution is the process by which cancer cells accumulate genetic changes over time, leading to increased heterogeneity and potential treatment resistance.

Define each of the following characteristics of cancer: Anaplasia, Hyperplasia, Metastasis

* Hyperplasia: 
* Uncontrolled cell division
* Immortal and Invasive


* Anaplasia:
* Structure/function of cell is undifferentiated


* Metastasis
* Ability to move to and establish tumors at other sites in body

What is an oncogene? Give an example and describe a situation in which this oncogene contributes to cancer.

An oncogene is a mutated form of a proto-oncogene. They allow good cells to divide normally. When mutated, they allow too many cells to divide which leads to inappropriate cell division and tumor development.

What is a tumor suppressor gene? Give an example and describe a situation in which this tumor suppressor gene contributes to cancer

Tumor suppressor genes normally prevent bad cells from dividing. If there is a mutated tumor suppressor gene that turns its action off in the cell, then it can no longer prevent the bad cell from dividing and a tumor can result.

Compare and contrast the action of tumor suppressor genes and oncogenes.

Tumor suppressor genes normally prevent bad cells from dividing. If we have a LOSS OF FUNCTION in a tumor suppressor gene that turns its action off in the cell, then it can no longer prevent the bad cell from dividing and a tumor can result. Proto-oncogenes allow good cells to divide. However, a GAIN OF FUNCTION mutation in a proto-oncogene converts it to an oncogene that is always on – leading to inappropriate cell division and tumor development. Note that the proto-oncogene is the normally functioning gene. The mutated form is said to be an oncogene.

How to tumor suppressor genes and oncogenes relate to parts of a car?

Tumor suppressors are the brakes, oncogenes are the gas petal. If you do not stop at a stop sign because your brakes give out – you may go into the intersection and have an accident. This is like the loss of function of a tumor suppressor gene at a cell cycle checkpoint. If you floor the gas pedal as you round a bend in the road, you may wipe out and crash into a tree. This is like the over-action of the oncogene.

What types of cancers are associated with the RB, BRCA1 and BRCA2 genes? Are these genes oncogenes or tumor suppressor genes?

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* BRCA1 and BRCA2 are important in some cases of breast and ovarian cancer
* RB is implicated in various cancers, but gets its name because it was first correlated with retinoblastoma.

Discuss the role of p53 in cancers. Is it a tumor suppressor gene or oncogene? Why is this gene like the fork in the road?

* Associated with these types of cancers: __colon, lung, breast, and brain cancer__
* Functions at the __G1/S__ checkpoint
* Tumor suppressor gene


* Analogous to a fork in the road because __the action of p53 determines whether a damaged cell is paused until repairs can be made or whether the damaged cell is too badly damaged to repair and programmed cell death (or apoptosis) occurs.__

Define apoptosis and describe why it is important in preventing cancer

Apoptosis is a **natural process of programmed cell death** that occurs in multicellular organisms. It is important in preventing cancer because it helps to **eliminate cells that are damaged, mutated, or no longer needed,** before they have a chance to divide and potentially form cancerous tumors.