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Genetics
Basic Genetics
163
Health Care
Undergraduate 3
12/10/2012

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Term
Epigenetics
Definition
Changes to the chemical groups that associate with DNA profoundly affect which parts of the genome are accessible to the transcription factors and under which conditions. Such changes to the molecules that bind to DNA that are transmitted to daughter cells when the cell divides are termed epigenetic.
Term
Proteomics
Definition
A more complex portrait of gene expression which considers all the proteins made in a cell, tissue, gland, organ, or entire body.
Term
Chromatin Remodeling
Definition
interactions of the histone proteins associated with DNA with other chemical groups expose some sections of DNA to transcription factors and shield other sections, blocking their expression.
Term
Three major types of small molecules that bind to histones.
Definition
Acetyl group, methyl groups, and phosphate groups. They key to the role that histones play in controlling gene expression lies in the acetyl groups. They bind to specific sites on the histones particularly the amino acid lysine. Acetyl binding can shift histone interactions in a way that eases transcription.
Term
microRNAs
Definition
bind to the 3 end of certain mRNAs preventing their translation into protein. Overall, these two processes determine the ebb and flow of different proteins, enabling cells to adapt to changing conditions.
Term
Chromatin Remodeling can be compared to
Definition
on/off switch
Term
microRNAs can be compared to
Definition
dimmer switch
Term
thalasssemia mental retardation syndrome
Definition
anemia and mental retardation causes by undermetylation of heterochromatin.
Term
ICF syndrome
Definition
immunodeficiency, unstable centromeres, facial anomalies caused by of undermethylation of DNA repeats.
Term
Rett Syndrome
Definition
repetitive movements, irregular breathing, seizures, loss of motor control, and neurodegeneration caused by a failure to remove acetyls from histones on gene DLX5 expressed in the brain.
Term
Rubinstein-Taybi syndrome
Definition
mental retardation, short stature, and facial anomalies caused by acetyl groups being added inappropriately to certain histones.
Term
RNA interference
Definition
a biological mechanism by which dsRNA induces gene silencing by targeting complementary mRNA for degradation.
Term
Epigenetics and Diet
Definition
High levels of methionine can be found in sesame seeds, Brazil nuts, fish, meats and some other plant seeds; methionine is also found in cereal grains. Most fruits and vegetables contain very little of it.
Term
Fragile X Syndrome
Definition
In people with fragile X syndrome, the CpG island is methylated. As a result, the cell is unable to copy the information in the FMR1 gene. Since an mRNA copy is not made, FMRP will not be synthesized. Since there is no FMRP at the time and place it is needed, the characteristics of fragile X syndrome are set in motion.
Much of the focus on fragile X syndrome is on the expansion of the repeated CGG's. It is technically not the expansion that directly causes the problem. Instead, having more than 230 CGG repeats sets in motion methylation of part of the FMR1 gene. The methylation stops the synthesis of FMRP and the absence of FMRP causes fragile X syndrome. We do not know why having too many CGG repeats triggers methylation.
Term
Transcription
Definition
production of mRNA
Term
Translation
Definition
production of protein
Term
Three major types of RNA
Definition
messenger RNA, ribosomal RNA, transfer RNA
Term
mRNA
Definition
carries information that specifies a particular protein. Produced in the nucleus. Transported to the ribosome. A three nucleotide codon specifies a particular amino acid. Most mRNAs are 500-4,500 bases long.
Term
Transcription Factors
Definition
in bacteria, operons control gene expression. In more complex organisms transcription factors control gene expression and link genome to environment. These contain DNA-binding domains. About 2,000 in humans. Mutations in transcription factors may cause a wide range of effects.
Term
three steps of transcription
Definition
initiation, elongation, termination.
Term
Start and Stop Codons
Definition
Start- AUG
Stop-UAA,UAG,UGA
Term
Translation
Definition
requires mRNA, tRNAs, ribosomes, energy molecules, and protein factors.
Term
Four levels of protein structure
Definition
primary, secondary, tertiary, quaternary.
Term
Disorders associated with protein misfolding
Definition
alzhemier disease, familial amyotrophic lateral sclerosis, huntington disease, parkinson disease, lewy body dementia, PKU, Prion disorders
Term
PKU
Definition
Cause is a defect in the enzyme phenylalanine hydroxylase
Symptoms include seizures, delayed development, behavioral problems, psychiatric disorders, musty or mouse like odor, lighter skin and hair, and skin disorders such as eczema.
Lab testing using inhibition assay or microfluorometric assay.
Term
Prions
Definition
Prion protein can fold into any of the several conformations.
One conformation is aberrant. Moreover, it can be passed on to other prions upon contact, propagating like an “infectious” agent. In addition, the aberrant conformation can form even in the wild-type protein.

Prion diseases are called transmissible spongiform encephalopathies. Example: scrapie, kuru, bovine spongiform encephalopathy.
Term
Pseudogenes
Definition
similar in sequence to a particular protein encoding gene, and it may be transcribed into RNA, but it is not translated into protein.
Term
Transposon
Definition
most abundant type of repeat in a sequence of DNA that can jump about the genome.
Term
Mutation
Definition
a change in DNA that is present in less than %1 of a population. May occur at the DNA or chromosome level.
Term
Mutant
Definition
usually refers to the phenotype. Usually connotes an abnormal or unusual variant.
Term
Germline mutations
Definition
Change occurs during the DNA replication that precedes meiosis
Term
Somatic mutations
Definition
happens during DNA replication before a mitotic cell division
Term
Sickle Cell Anemia
Definition
Results from a single DNA base change in the beta globin gene, which replaces glutamic acid with valine. Phenotype associated with homozygotes. Creates sickle shape of RBC. Sickling causes anemia, joint pain, and organ damage when RBC become lodged in small blood vessels.
Term
Thalassemia
Definition
beta hemoglobin mutation. Two few beta chains. Major=homozygous. Minor=heterozygous
Term
Collagen
Definition
a major component of connective tissue. Accounts for 60% of protein in bone and cartilage. Precise structure: triple helix of two polypeptides. Longer precurser procollagen is trimmed to form collagen.
Term
Ehler-Danos Syndrome
Definition
Collagen molecules cannot assemble, so skin becomes stretchy. It blocks the trimming of pro collagen to collagen.
Term
Mutagen
Definition
an agent that causes a mutation
Term
Spontaneous Mutation Rate
Definition
rate differs between genes, each human has about 1 in 100,000 chance of mutating. Each individual has multiple new mutations. Mitochnodrial genes mutate at a higher rate than nuclear genes because they cannot repair their DNA.
Term
Mutation Rate of autosomal genes
Definition
mutation rate=number of new cases/2x where x is the number of individuals examined.
Term
Induced mutations
Definition
caused by mutagens, many are also carcinogens and cause cancer.
Term
Examples of induced mutations
Definition
alkylating agents- remove a base
acridine dyes- add or remove a base
x rays-break chromosomes
uv radiation-creates thymine dimmers
Term
site directed mutagenesis
Definition
changes a gene in a desired way.
Term
Causes of mutagens
Definition
the natural environment accounts for 81% of mutagens. Contributions from medical procedures are relatively minor. They are measured in millirems. The annual exposure of 360 millirems. 4,000-6,000 millirems is lethal.
Term
Point mutations
Definition
change a single nucleotide
Term
transition
Definition
purine replaces purine, pyrimadine changes pyrimadine.
Term
transversion
Definition
purine replaces pyrimadine. This can cause issues.
Term
Missense mutation
Definition
changes a codon that normally specifies a specific amino acid into another amino acid.
Term
Nonsense mutation
Definition
turns into a stop codon
Term
splice site mutation
Definition
alters a site where an intron is removed from mRNA. Can affect the phenotype if the intron is translated or the exon is skipped. An example of an exon getting skipped is familial dysautonomia.
Term
Frameshift mutation
Definition
a change that alters the reading frame
Term
Deletion mutation
Definition
removes genetic material. Removal of three or a multiple of three bases will not cause a frameshift, but can still alter the phenotype.
Term
Insertion mutation
Definition
adds DNA and it, too, can offset a gene's reading frame.
Term
Tandem duplication
Definition
an insertion of identical sequences side by side.
Term
CNV (copy number varient)
Definition
a sequence that vary in number from person to person. Range account for about 1/4 of our genome. Common among people with behavioral disorders.
Term
Silent mutations
Definition
mutations that do not alter the encoded amino acid.
Term
photoreactivation repair
Definition
humans do not have this type of repair. Photolyases absorb energy from visible light and use it to detect and bind to pyrimidine dimmers then break the extra bond.
Term
excision repair
Definition
enzymes cut the bond between DNA and snip out the pyrimidine dimmer surrounding the bases. DNA polymerase fills the in the correct nucleotides using the exposed template as guide. Nucleotide excision repair repairs up to 30 nucleotides.
Term
base excision repair
Definition
Base excision repair replaces 1-5 nucleotides. Repairs errors due to oxidative causes.
Term
mismatch repair
Definition
enzymes proofread newly replicated DNA for small loops that emerge from the double helix. The enzymes excise the mismatched base so that it can be replaced.
Term
conditional mutation
Definition
affects the phenotype only under certain conditions. This can be protective if an individual avoids the exposures that trigger symptoms.
Term
failure of DNA repair
Definition
if both copies of a repair gene are a mutant, a disorder can result. If damage is too severe p53 increases death rate. Mutations in genes encoding DNA repair proteins directly increases susceptibility to certain types of cancer.
Term
Hereditary nonpolyposis colon cancer
Definition
affects 1/200 individuals. Defect in mismatch repair. HN{CC gene is on chromosome 2.
Term
Xeroderma pigmentosum
Definition
autosomal recessive, seven genes involved. Malfunction of nucleotide excision repair or deficient "sloppy" DNA polymerase.
Term
cytogenetics
Definition
a subdiscipline within genetics that links chromosome variations to specific traits and illnesses.
Term
subtelomeres
Definition
the region between the centromere and the telomeres.
Term
Centromere positions
Definition
At tip: telocentric
close to end: acrocentric
off center: submetacentric
at midpoint: metacentric
Term
amniocentesis
Definition
detects about 1,000 of the more than 5,000 known chromosomal and biochemical problems. Ultrasound is used to follow needle's movement. Risk for miscarriage is about 1 in 1,000
Term
Chorionic Villi Sampling
Definition
performed during the 10th to 12th week of pregnancy. Provides earlier results than amniocentesis. However it does not detect metabolic problems. Has a greater risk of spontaneous abortion. Chance of spontaneous abortion is also pretty high.
Term
Fetal Cell Sorting
Definition
a new technique detects fetal mRNA in the bloodstream of the mother. Easy to tell if baby boy.
Term
FISH
Definition
fluorescence in situ hybridization (FISH) introduces the ability to highlight individual genes. More precise and targeted that conventional chromosome staining becaue it uses DNA probes that are complementary to specific DNA sequences.
Term
polyploid
Definition
a cell with an extra set of chromosomes.
Term
triploid
Definition
an individual whose cells have three copies of each chromosome. Most result from the fertilization of 2 sperm
Term
aneuploid
Definition
cells missing a single chromosome or having an extra one.
Term
euploid
Definition
normal number of chromosomes.
Term
nondisjunction
Definition
the meiotic error that causes aneuploidy is called nondisjunction. A chromosome pair fails to separate at anaphase of either the first or second meiotic division.
Term
trisomy 21
Definition
down syndrome. Most common autosomal aneuploid. A person with down syndrome is usually short and has straight, sparse hair and a tongue protruding through thick lips. The hands have an abnormal pattern of creases, the joints are loose, and poor reflexes and muscle tone give a "floppy" appearance.
Term
trisomy 18
Definition
Edward syndrome. great physical and mental disabilities, with developmental skills usually stalled at the 6 month level. Major abnormalities include heart defects, displaced liver, growth retardation, and oddly clenched fists.
Term
trisomy 13
Definition
patau syndrome. fusiong of the developing eyes, so that a fetus has one large eyelike structure in the center of the face. More common is a small or absent eye. Major abnormalities often affect the heart, kidneys, brain, face, and limbs.
Term
XO syndrome
Definition
Turner's syndrome. 1 in 2,500 female births. 99% of affected fetuses die in utero. Don’t have a second sex chromosome. For the most part look normal. Hands and feet can be puffy. You can determine by the webbing on the back of their neck. Shorter than normal. Common to have ear infections. Never reach sexual maturity. While in the womb all their eggs mature. They can never produce mature eggs. Normal intelligence. Because of early menopause they have high risk of osteoporosis, colon cancer, etc. Normal life expectancy. No male equivalent.
Term
Triplo-x
Definition
Xxx 1 in 1,000 births. Usually taller than average. Look different but not huge difference. Intelligence usually less than normal.
Term
XXY
Definition
Klinefelter syndrome. 1 in 500 male.Make them more feminine in characteristics. Sparse body hair and facial hair. Increased breast tissue. Most men don’t know until they are trying to have children. Some decreased intelligence. Do create some normal sperm.
Term
XXYY
Definition
Likely arises due to unusual oocyte and sperm. ADD, ocd, learning disabilities, individuals are infertile. Treated with testosterone. Common to have ulcers in feet and legs.
Term
XYY
Definition
1 in 1,000 male births.
96% phenotypically normal. Modest phenotypes may include great height, acne, speech, and reading disabilities. Studies suggest increase in aggressive behavior are not supported.
Term
Cat Cry Syndrome
Definition
deletion of part of the 5th chromosome. Deletion of the shorter arm. Children are pretty normal. Some behavioral issues.
Term
deletions and duplications
Definition
are missing and extra DNA sequences, respectively. They are types of copy number variants. Deletions and duplications can arise from chromosome rearrangements. These include translocations, inversions, and ring chromosomes.
Term
Translocation
Definition
different nonhomologous chromosomes exchange or combine parts.
Term
Robertsonian translocation
Definition
the short arms of two different acrocentric chromosomes break, leaving sticky ends on the two longer arms that join, forming a single large chromosome with two long arms.
Term
Reciprocal translocation
Definition
two different chromosomes exchange parts. About 1 in 500 people is a carrier for translocation.
Term
paracentric inversion
Definition
a single crossover within the inverted segment gives rise to two normal and two very abnormal chromosomes. The other two chromosomes are normal.
Term
pericentric inversion
Definition
includes the centromere within the loop. A crossover in it produces two chromosomes that have duplications and deletions, but one centromere each.
Term
Isochromosomes
Definition
a chromosomes that has identical arms. This occurs when, during division, the centromeres part in the wrong place.
Term
Ring Chromosomes
Definition
chromosomes shaped like rings form in 1 out of 25,000 conceptions. Ring chromosomes may arise when telomeres are lost, leaving sticky ends that adhere.
Term
Uniparental Disomy
Definition
occurs when a person receives two copies of a chromosome, or part of a chromosome, from one parent and no copies from the other parent. UPD can occur as a random event during the formation of egg or sperm cells or may happen in early fetal development.
In many cases, UPD likely has no effect on health or development. Because most genes are not imprinted, it doesn’t matter if a person inherits both copies from one parent instead of one copy from each parent. In some cases, however, it does make a difference whether a gene is inherited from a person’s mother or father. A person with UPD may lack any active copies of essential genes that undergo genomic imprinting. This loss of gene function can lead to delayed development, mental retardation, or other medical problems.
Term
Prader-Willi Syndrome, Angelman Syndrome
Definition
caused by UPD or other errors in imprinting involving genes on the longer arm of chromosome 15.
Term
Function of the Immune System
Definition
protection against infection is based on the ability of the immune system to recognize foreign or nonself cell surfaces that are not part of the boyd. These include surfaces of microorganisms such as bacteria and yeast; nonliving infectious agents such as viruses and prions; and tumor cells and transplanted cells.
Term
Blood Groups
Definition
A,B,O,AB. 29 major blood groups. Common RBC antigens. For more than a century blood was typed by an approach called serology. The newer way is to identify the instructions for the cell-surface antigens. This is done by genotyping
Term
Major Histocompatibility Complex
Definition
many of the proteins on our cell surfaces are encoded by genes that are part of a 6 million base long cluster on the short arm of chromosome 6. Provides 50% of immunity. MHC I an II encode human leukocyte antigens. MHC I is found on any cell type. MHC II is found on antigen presenting cells. MHC II encode blood plasma.
Term
macrophages
Definition
are antigen presenting cells. A macrophage engulfs a bacterium, then displays the foreign antigens on its surface, which are held in place by MHC self proteins. This event sets in motion many immune reactions.
Term
Innate immunity
Definition
immediate generalized immunity. Skin, mucous membranes, earwax, and waving cilia in the respiratory tract are examples if innate immunity. Inflammation is the central response of innate immunity. Creates a hostile environment for certain types of pathogens.
Term
Cytokines
Definition
play a role in innate and adaptive immunity. Cytokines called interferons alert other components of the immune system to the presence of cells infected with viruses.
Term
Interleukins
Definition
cytokines that cause fever, temporarily triggering a higher body temperature that directly kills some infecting bacteria and viruses.
Term
Tumor Necrosis Factor
Definition
another type of cytokine that activates other protective biochemicals, destroys certain bacterial toxins, and attacks cancer cells.
Term
Humoral Immune Response
Definition
B Cell produce antibodies in response to activation by T cells.
Term
Cellular immune response
Definition
T cells produce cytokines and activate other cells.
Term
Adaptive Immunities three basic characteristics
Definition
it is diverse, specific, and remembers.
Term
Humoral Response steps
Definition
In the humoral response B cells proliferate and mature into antibody-secreting plasma cells. Only the b cells that bind the antigen proliferate. Its descendants may develop into memory cells or plasma cells. Plasma cells greatly outnumber memory cells.
Term
Antibody structure
Definition
The simplest antibody molecule and consists of four polypeptide chains, heavy and two light, joined by pairs of sulfur atoms that form disulfide bonds.
Term
IgA
Definition
located in milk, saliva, urine, tears, and digestive secretions. Protects against pathogens at points of entry into the body.
Term
IgD
Definition
on B cells in blood. Stimulate B cells to make other types of antibodies, particularly in infants.
Term
IgE
Definition
in secretions with IgA and in mast cells in tissues. Acts as a receptor for antigens that cause mast cells to secrete allergy mediators.
Term
IgG
Definition
blood plasma and tissue fluid, passes to fetus. Protects against bacteria, viruses, and toxins especially in the secondary immune response.
Term
IgM
Definition
Blood plasma. Fights bacteria in primary immune function, includes anti A and anti B antibodies of ABO group.
Term
Helper T Cells
Definition
recognize foreign antigens on macrophages, stimulate B cells to produce antibodies, secrete cytokines, and activate another type of T cell called cytotoxic T cell. Regulatory T cells formerly known as suppressor T cells are subpopulation of T cells which modulate the immune system, maintain tolerance to self antigens, and abrogate autoimmune disease.
Term
Severe combined immune deficiencies
Definition
affect humoral and cellular immunity. About half of SCID cases are X linked. In less severe forms the individual lacks B cells but has some T cells.
Term
HIV
Definition
an infectious viruses enters the body with direct contact of bodily fluids. Infects macrophages, and later, helper T cells. Virus replicates and bursts out of help T cell, killing it. Loss of helper T cells prevents B cells from activating. Infections occur because the immune system is not functioning. Replicates rapidly, mutates easily, and can hide.
Term
Steps of HIV infection
Definition
HIV binds to help T cell. The part of the HIV that binds to the help T cell is called gp120. The carb chains that shield the protein part of gp120 move aside as they approach the cell surface, and the viral molecule can now bind to a CD4 receptor.
Term
AIDS
Definition
AIDS is the disease that results from HIV infection. The immune system impact of HIV infection has progressed to impairment of immune function. Due to genetically diverse population of HIV in human host, treatment requires combination of medication. Drugs block/inhibit different points of infection. Entry of virus into t cells, replication of viral genetic material, processing of viral proteins.
Term
CCR5 gene
Definition
encodes for a receptor protein on a cell membrane. Individuals homozygous for 32 base deletion of CCR5 are resistant to infection. Heterozygous individuals become infected but stay healthy for several years longer than people that do not have the mutation. Same mutation may have enabled people to survive the plague in Europe during the Middle Ages.
Term
Autoimmunity
Definition
immune system attacks the tissues of an individuals own body. Autoantibodies recognize self proteins. About 5% of the population has an autoimmune disorder. The signs and symptoms reflect the type of cells under attack.
Term
1) How autoimmunity arises
Definition
A virus replicating in a cell incorporates proteins from the cells surface onto its own. When the immune system learns the surface of the virus to destroy it also learns to attack human cells that normally bear the protein.
Term
2) how autoimmunity arises
Definition
Some cells that should have died in the thymus somehow escape the massive die-off, persisting to attack self tissue later on.
Term
3) how autoimmunity may arise
Definition
A nonself antigen coincidentally resembles a self antigen, and the immune system attacks both. In rheumatic fever, antigens on the heart valve resemble those on streptococcus bacteria, antibodies produced to fight a strep throat also attack the heart valve cells.
Term
4) how autoimmunity may arise
Definition
If X inactivation is skewed, a female may have a few cells the express the X chromosome genes of one parent. The immune system may respond to these cells as foreign if they have surface antigens that are not also on the majority of cells. This may explain why autoimmune disorders are more common in females.
Term
Allergy
Definition
Immune response to a non-threatening foreign substance called an allergen. Size of allergens may determine type of allergic response. Large remains in upper respiratory tract, small can infiltrate the lungs. Asthma is a chronic disease. Contraction of the airways, inflammation and mucus production block air flow.
Term
Allergic response
Definition
Humoral and cellular immunity are involved. IgE antibodies are made and bind mast cells. Mast cells release allergy mediators like histamine and heparine that cause inflammation, runny eyes and nose, rashes, and asthma.
Allergens activate a class of helper T cells that release cytokines. Severe allergic reaction though out the body is called anaphylactic shock.
Term
Rh factor
Definition
Rh is the rhesus factor. A person is Rh+ if the red blood cells have surface molecules called RhD antigen. Fetal cells entering the pregnant woman's bloodstream can stimulate her immune system to make anti Rh antibodies if the fetus is Rh+ and she is Rh-. A drug called RhoGAM prevents attack on subsequent fetuses.
Term
Vaccine
Definition
an inactive or partial form of a pathogen that stimulates the immune system to alert B cells to produce antibodies. When the person then encounters the natural pathogen, a secondary immune response ensues, even before symptoms arise. Vaccines consisting of entire viruses or bacteria can, rarely, cause illness if they mutate to a pathogenic form.
Term
Immunotherapy
Definition
medical treatment used to amplify or redirect the immune response. Monoclonal antibodies (MAb) Useful in detecting and targeting one particular antigen. In 1975 british researchers devised a technology which mass-produces a single B cell. Thus, preserving its spciicity an amplifying its antibody type. Uses are in basic research and disease diagnosis, home pregnancy strips, and herceptin.
Term
Uses of cytokines
Definition
cytokines are used to treat a variety of conditions. Interferons were the first cytokines to be tested on a large scale. Interleukin 2 is a cytokine that was administered intravenously to treat kidney cancer recurrence.
Term
Autograft
Definition
transfers tissue from one part of a person's body to another.
Term
Isograft
Definition
tissue from a monozygotic twin
Term
Allograft
Definition
comes from an individual who is not genetically identical to the recipient, but a member of the same species
Term
xenograft
Definition
tissue from one species to another.
Term
Cancer
Definition
cancer is genetic, but not usually inherited. Cancer is a group of diseases caused by a loss of cell cycle control. If a cell escapes normal control over its division rate, it forms a growth called a tumor.
Term
Metastasis
Definition
the process of cancer spreading
Term
Tumor suppressor gene
Definition
there are more than 30 tumor suppressor genes, which cause cancer whey they are deleted or inactivated. The normal function of a tumor suppressor gene is to keep the cell cycle running at the appropriate rate for a particular cell type under particular conditions.
Term
Cell Cycle Control
Definition
timing, rate, and number of cell divisions depend on: protein growth factors, signaling molecules from outside the cell, transcription factors within. Checkpoints control the cell cycle.
Term
Telomerase
Definition
gametes keep their telomeres longer thanks to the enzyme telomerase, that is a complex of RNA and protein. Part of the RNA the sequence AAUCCC serves as a template for the template for the 6DNA base TTAGGG that builds telomeres. Telomerase moves down the DNA likea sipper adding six teeth base at a time.
Term
Somatic Mutations
Definition
occur sporadically in nonsex cells. Result from a single dominant mutation or two recessive mutations in the same gene. Cancer susceptibility not passed on to offspring.
Term
Germline mutations
Definition
cancer susceptibility passed on to the offspring. Usually requires second somatic mutation. Rare but strike earlier than sporadic cancers.
Term
dedifferentiated
Definition
a cancer cell can become less specialized than the normal cell types near it that it might have descended from.
Term
Angiogenesis
Definition
cancer cells recruit their own capillaries.
Term
How does cancer begin at a cellular level
Definition
activation of a stem cell that produce cancer cells. Dedifferentiation occurs. There is then an increase in the proportion of tissue that consists of stem or progenitor cells. Faulty tissue repair
Term
Proto-Oncogenes
Definition
normal versions of genes that promote cell division. Called oncogenes in their mutated form.
Term
Oncogenes
Definition
overexpression of normal function
Viruses integrated next to proto-oncogne. Moving a proto-oncogne next to a highly transcribed gene. Ex Burkitt lymphoma. People infected with Epstein barr virus A translocation places a proto-oncogne on chromosome 8 next to an antibody gene on chromosome 14. The oncogene is over expressed, and the cell division rate increase.
Term
fusion proteins
Definition
an oncogene is also activated when a proto-oncogene moves next to another gene, and the gene pair is transcribed and translated together, as if they are one gene. Ex promyelocytic leukemia.
Term
Her-2/neu
Definition
product of oncogene. Excessive levels in approx 25% of breast cancer patients. Too many tyrosi receptors. Send too many signals to divide. The drug herceptin binds to the receptors. The signal is blocked so the division is no longer out of control.
Term
Tumor Suppressor Genes
Definition
tumor suppressor genes normally stop a cell from dividing. Mutations of both copies of a tumor suppressor gene is usually required to allow cell division.
Term
Retinoblastoma
Definition
a rare childhood cancer. The RB gene is on chromosome 13. They harbor one germline mutant allele for the RB gene in each of their cells. Cancer develops in any somatic cell where the second copy of the RB gene mutates.
Term
p53 gene
Definition
guardian of the genome. Determines if a cell has repaired DNA damage. More than 50% of human cancers involve an abnormal p53 gene. Rare inherited mutations in the p53 gene causes a disease called li-fraumeni syndrome. Family members have many different types of cancer at early ages.
Term
Breast Cancer
Definition
familial: a germline mutation is inherited and then a somatic mutation occurs in the breast cell.
Sporadic: two somatic mutations affect the same cell.
Term
BRCA
Definition
Two major breast cancer susceptibility genes are BRCA1 and BRCA2. Encode proteins that join two others to form a complex that allows repair of double stranded DNA breaks. Normally protein complex that includes BRCA1 and BRCA2 allows other cell cycle genes to repair. If they are messed up the cells aren't repaired. You then get messed up DNA that you don't want.
Term
MicroRNAs
Definition
normally control the expression of proto-oncogenes and tumor suppressor genes. When microRNAs themselves have mutations or their expression is too high or too low, cancer can result.
Term
Gatekeeper genes
Definition
directly control mitosis and apoptosis
Term
Carekeeper genes
Definition
control mutation rates and have an overall effect when mutant is destabilizing the genome.
Term
New types of cancer drugs
Definition
stimulate cells to regain specialized characteristics, inhibit telomerase, induce apoptosis, inhibit angiogenesis.
Term
Hominin
Definition
Ancestory to humans, 6 million years ago hominin line broke off from apes.
Term
Autralopithecus
Definition
2-4 million years ago. Bipedal, not a tree dweller. Several species flat skull bases. Stood 4 to 5 feet tall. Humanlike teeth. Brain size of a gorilla. Hunter gatherer lifestyle.
Term
Homo Erectus
Definition
1 million years ago. Shallow forehead, massive brow ridge, brain about 1/3 the size of a modern human. Angled skull base, possible speech. Social, cooperative, used fire. Found in China, Java, Africa, Europe, and SE Asia. Pockets may have persisted until about 35,000 years ago.
Term
Homo Sapiens
Definition
Lived about 156,000 years ago. Physically similar to modern humans. Probably resembled Australian Aborigines
Term
Homo Neanderthalensis
Definition
split from human lineage about 516,00 years ago. Lived all over Europe. Reconstructions of skeletons indicates major differences between us. Larger brains, prominent brow arches. Muscular jaws, distinct spacing of teeth. Large barrel shaped chest. Powerfully built.
Term
Neanderthal life
Definition
coexisted with the lighter-weight cro-magnons from 30,000-40,000 years ago.
Neanderthals buried their dead and placed flowers on their deceased.
Use of flint spears for hunting
For reasons unknown, by 28,000 yearso ago Neanderthals disappeared (through disease, competition, or changing environment)
Analyzing Neanderthal DNA is difficult because it is rare, and often contaminated by handlers
Using ancient DNA and mitochondrial DNA clocks indicates that Neanderthals were a side branch of our family tree
Neanderthals and our direct ancestors parted ways before humans left Africa
Non-African modern human genome is 1-4% Neanderthal
Term
Denisovians
Definition
Access to one Denisovian sample (siberia) Alleles for brown skin, hair, and eyes. Range New Guinea population contains. 6% Denisovian DNA.
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