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| What is cancer? | o When meiosis goes wrong. Begins from the growth of a single abnormal cell. A mutation occurs, allowing a cell to undergo inappropriate cell division. Division produces more abnormal cells (have no cell division limit) |
| Somatic Cells | sporadic cancer only affecting the individual (not inherited) |
| Germline Cells | mutations that are inherited (usually require second somatic mutation) |
| Are cancers caused by a single mutation, or is more than one needed? | Oncogenes= More than 100 caused when inappropriately turned “on” usually more than 1 |
| What is the significance of telomerase? | is the enzyme (complex of RNA and protein) that adds telomere sequences to the ends of chromosomes--puts a lifespan on cells |
| Know the various characteristics of cancer cells that make them different from normal cells. | Normal, specialized cells have telomerase turned off, limits cell division. Cancer cells have to express telomerase to be able to divide indefinitely |
| What are the two ways that cancer cells can be derived during the process of stem cell differentiation? | Germline or Sporatic |
| Germline (inherited cancer) | every cell has mutation, increases risk for cancer. cancer requires more than 1 gene mutation; if another mutation occurs then disease starts |
| Sporadic cancer | mutation has to occur in that specific tissue (takes 2 mutations) not born with any mutations |
| What is dedifferentiation? | Lose their specialized identity (not stem cells) Specialized cells lost some of their distinguishing features |
| How can cancer result from too many stem cells? | Some stem cells divide making too many causing abnormal growth because making too many and cant stop dividing |
| Cancer formation and Acute injuries | when every now and then you have an injury and repairs cells. Resting stem cells that are activated and fill in the gaps when need repair |
| Cancer formation and Chronic injuries | when repair system goes bad and add too many stem cells which causes stem cells to differentiate into cancer cell. Persistent activation of stem cells |
| What are oncogenes? | Proto-oncogenes are called oncogenes in their mutated form |
| What are proto-oncogenes? | Proto-oncogenes are normal versions of genes that promote cell division |
| • Expression of proto-oncogenes at the wrong time or in the wrong cell type leads to what? | cell division and cancer |
| ______ copy (ies) of an oncogenic mutation is sufficient to promote cell division and occurs through _____ mutation. | One, point mutation |
| ________ integrated next to a proto-oncogene can cause transcription when it is transcribed | Viruses |
| Moving a proto-oncogene to a new location can separate the coding region from regulatory regions of the gene leading to | incorrect expression |
| Moving a proto-oncogene next to a highly transcribed gene can lead to | erroneous transcription of the proto-oncogene |
| Know the various ways that oncogenes can be activated | activated by translocation= can separate the coding region from regulatory regions of the gene leading to incorrect (nonstop) expression or get changed by viruses if next to an oncogene can turn on transcription when its not suppose to be |
| What are tumor suppressor genes? | Regulate cell division (# & rate) Cancer can be caused by loss of genes that inhibit cell division. Tumor suppressor genes normally stop a cell from dividing (prevents things from happening) Mutations of both copies of a tumor suppressor gene is usually required to allow cell division |
| What are examples of tumor suppressor genes? | Examples include: Wilms’ tumor, retinoblastoma gene, p53 gene, and BRCA1 |
| How many mutations are requires for retinoblastoma to develop? | Two mutations are required-One in each copy of the RB gene. |
| For sporadic cases, Retinoblastoma is a result of | two somatic mutations |
| For familial cases, Retinoblastoma is a result of | Retinoblastoma is inherited as an autosomal recessive mutation followed by a somatic mutation in the normal allele. The chance of a second somatic mutation is high. Creates a “susceptibility” to cancer in the family |
| What is the significance of the p53 gene | (job to proofread DNA) acts as a cell cycle protein. Determines if a cell has repaired DNA damage. If damage cannot be repaired, p53 can induce apoptosis (too far gone alerts another cell) More that 50% of human cancers involve an abnormal p53 gene (goes wrong in a big way) |
| Rare inherited mutations in the p53 gene cause a disease called | Li-Fraumeni syndrome- Family members have many different types of cancer at early ages. |
| Know the various environmental causes of cancer. | Exposure to carcinogens increases risk. Smoking increases lung cancer incidence. Exposure to radiation. Burns from overexposure to sunlight can cause skin cancer. Variation in diet. Fatty diets are correlated with increased estrogen and increased breast cancer. “Chemopreventative” nutrients may help decrease risk |
| What is the underlying reason why biotechnology is possible? | Use or alteration of cells or biological molecules for specific application. Transgenic organisms are possible because the genetic code is universal |
| What does PCR stand for and what does it do? | Polymerase chain reaction. Increases the amount of a DNA sequence in a tube. Replicates sequence millions of times |
| What are the four components needed for a PCR reaction and what do they do? | Free nucleotides (building blocks) Primers (starting point) Polymerase (make copies) Target sequence * heating up DNA then lower temp. so primers can line up to complementarily bases. Primers start sequence then polymerase fills in between the 2 primers. Then process continues again and again to make more copies. * |
| What is a restriction enzyme and how does it work? | Specific for specific sequence of DNA and cut in half when seen target sequence. Cut DNA from donor and recipient with the same restriction enzymes. Cut DNA fragment is combined with a vector |
| Vector DNA | moves and copies DNA fragment of interest |
| What are “sticky ends”? | DNA cut at an angle by a restriction enzyme cut at different points At specific sequence, the over hang called “sticky end” it attracts polymerase who wants to finish the sequence then ligase seals DNA |
| What kinds of vectors are used with recombinant DNA? | Vectors are commonly engineered to carry antibiotic resistance genes. Host bacteria without a plasmid die in the presence of the antibiotic. Bacteria harboring the vector survive. Growing cells on media with antibiotics ensures that all growing cells must carry the vector. Let them multiple then give them antibiotics and see which ones survivor (weed out ones don’t want by giving them antibiotics) |
| What is a genomic library? | (board; starting place) Collections of recombinant DNA that contain pieces of the genome (all an organisms genes) Lots of bacteria with lots of segments |
| What method is used to find specific DNA fragments within a genomic library? | DNA probe = radioactively (or fluorescently) labeled gene fragments. Tag organism let them multiple then know which segment |
| How does a genomic library differ from a cDNA library? | Genomic library of protein encoding genes produced by extracting mRNA and using reverse trancriptase (to get cDNA have to work backwards) to make DNA |
| What is reverse transcriptase? | When you take mRNA and make DNA. It fills in the blanks of the mRNA to get DNA |
| What is cDNA? | Make DNA that matches RNA. “cloning” |
| How are antibiotic resistance genes used in recombinant DNA technology? | Vectors are commonly engineered. Host bacteria without a plasmid die in the presence of the antibiotic. Bacteria harboring the vector survive. Growing cells on media with antibiotics ensures that all growing cells must carry the vector (let them multiple then give them antibodies and see which ones survivor) |
| What are transgenic organisms? | When a recombinant DNA is applied to multicellular organisms, individuals must be bread to yield homozygous individuals (adding DNA segments to organisms that didn’t have them there to start) |
| Why is it easier to make transgenic plants than transgenic animals? | because a plant can be derived from somatic cells, a new plant can be grown from a cutting; animal development does not work this way |
| What does the bt gene do? | Specifies a protein that destroys the stomach lining of certain insect larva. Kills insects when they eat the plant, it is specific just to that insect, does not harm other animals or humans |
| Know the benefits of GM (genetically modified) crops. | Enhance nutrition, resistance to pests and diseases, delayed fruit ripening to extend shelf life, production of eatable vaccines, biodegradable plastics, control of plant height, coloring, size, number. |
| Know the risks of GM (genetically modified) crops. | Risks are uncontrollable, wild, displaces traditional production, harm to farmers and US companies because other nations boycott the GM products, can’t predict the long term consequences, and reduction of biodiversity. |
| What is bioremediation? | Detoxifies pollutants. Examples; use certain genes |
| What are DNA microarrays and what kinds of questions can they address? | Determines what’s active and what’s not; isolate mRNAs generates cDNA, label DNA with fluorescent tag- can tell whether a particular gene is on or off. Tells you what’s going on in the whole cell (community not just street), look at colors. |
| What are some of the reasons to seek genetic counseling? | Family history of abnormal chromonsomes. Elevated risk of single gene disorder. Family history of multifactorial disorders. Fam hx of cancer. founded on screens for newborns. allows early treatment or monitoring. screens for 50 conditions using tandem mass spectrometry |
| What types of genetic tests are available? | Carrier screen, prenatal, newborn screen, diagnostic, predisposition, predictive |
| How does enzyme replacement therapy work? | If you know the gene, you can use to manufacture protein, transgenic animal with genes. Recombinant DNA- make more enzymes. |
| What is Pompe disease? | also known as glycogen storage disease type II, it is an autosomal recessive inborn error, deficiency of one of the 40 types of enzymes found in the cell’s lysosomes leads to buildup of the carbohydrate glycogen,causes heart problem, flaccid muscles, infantile, juvenile, and adult forms |
| How is enzyme replacement therapy used to combat this disease? | the human gene for acid alpha-glucosidases was attached to a casein (milk protein) promoter and produced in rabbit milk and into Chinese hamster ovary cells. Both approaches were tested on babies and led to improved symptoms, lowered muscle glycogen, improved muscle function, and hearts that returned to normal size. Drug called myozyme |
| What is gene therapy? | Altering genes hopefully can provide a longer-lasting treatment, Treatments have been focused on inherited disorders with a known disease mechanism |
| How do germline gene therapy and somatic gene therapy differ? | Germline gene therapy – gamete or zygote alteration, heritable, not done in humans, transgenic organisms. Somatic gene therapy – specific cells, not heritable |
| How are ex vivo, in situ, and in vivo gene therapies different? | Ex vivo gene therapy alters cells outside of body , In situ gene therapy occurs in a localized area , In vivo gene therapy vector is introduced directly into the body; most invasive |
| What are some of the typical target tissues for gene therapy? | Endothelium can secrete needed proteins directly into bloodstream Skin skin grafts can secrete therapeutic proteins Muscle - accessible, comprises _ body mass and has a good blood supply Liver many functions and can regenerate Lungs are easily accessed with aerosol spray Nervous tissue many illnesses and injuries affect nervous system, hard to change neurons, Cancer about _ of current trials target cancer |
| What is adenosine deaminase deficiency and what medical condition does it cause? | Severe combined immune deficiency (SCID) can be caused by ADA deficiency, Lack of ADA blocks the breakdown of metabolic toxins to uric acid. Toxins destroy T cells and causes susceptibility to infections and cancer. Replacement of ADA in individuals genetically deficient was attempted |
| How is gene therapy used to combat adenosine deaminase deficiency? | Injections of PEG-ADA given to first child in 1986- Increased ADA levels and T cell survival -Improved immune function, White blood cells from a patient receive a functional copy of ADA and the cells are returned -Increased T cells present with functioning ADA gene. Stem cells from umbilical cord blood are isolated -Cells are treated to replace mutated ADA allele with normal allele and returned -T cells with normal allele accumulate in patient |
| What is ornithine transcarbamylase deficiency? | Deficiency of OTC is inherited as an X-linked recessive mutation -OTC normally breaks down amino acids present in protein -Lack of OTC allows buildup of ammonia, which damages brain function -Low-protein diets and ammonia-binding drugs are used to treat OTC deficiency |
| How has gene therapy been used to combat ornithine transcarbamylase deficiency? | Clinical trials to treat OTC deficiency were established using adenovirus as a vector for the normal OTC gene -Jesse Gelsinger had a mild OTC deficiency, volunteered for the OTC gene therapy trial and was accepted -Four days after gene therapy Jesse died of massive immune reaction and associated complications |
| What is Canavan disease | An aspartoacylase enzyme deficiency-Neurons release N-acetylaspartate (NAA)-NAA is normally broken down by the enzyme aspartoacylase to harmless components -Enzyme deficiency creates NAA buildup, which destroys oligodendrocytes.-Lack of oligodendrocytes prevents myelin formation and neurons cease functioning-Causes brain degeneration in children-First observed as inability to stand or sit, poor muscle control, poor vision, and lack of reaction to surroundings-Good gene therapy candidate because:-Gene and protein are well known-Window of time exists for treatment-Only the brain is affected-Brain scans can be used to monitor treatment-No existing treatment |
| • What is the Human Genome Project? | Genomes- an organism’s complete set of chromosomes (instruction manual for individual) Started with linkage maps (now greatly improved) Automated DNA sequencing increased resolution Positional cloning, RFLPs, and SNPs Officially started in 1990, $3 billion, 15 year project, ended 2005 Determined the order of the nucleotides present in each of the human chromosomes Draft of the human genome in February 2001 Represents the work of thousands of researchers in an international collaboration |
