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Published byRussell Stanley Modified over 9 years ago
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Gene mutationGene mutation Change in DNA base sequence Permanent Only inherited if occur in gametes 2 types Spontaneous Errors in normal processes, rare Ex. DNA segment moving from one location to another Induced Exposure dependent (ex. Chemicals, radiation)
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Basic TerminologyBasic Terminology Mutagens Environmental agents known to create mutations within DNA (ex. UV radiation) Carcinogens Mutagens that cause cancer “cancer-causing” Ex. Smoking, chemicals used in industries, DDT **Cancer—accumulation of mutations over time**
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What is so bad about radiation? FREE RADICALS ! ! ! React with DNA— MUTATION! Ex. X-Rays
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DNA Technology
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Gel ElectrophoresisGel Electrophoresis Laboratory process for DNA fragment separation. DNA separates based on the size of each DNA fragment Restriction enzyme sites (where enzymes will cut DNA) unique to each person SO expose DNA to restriction enzymes
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Latest TechnologyLatest Technology Getting rid of our reliance on gel electrophoresis….any problems with old method? Fluorescent labeling of DNA fragments Creates a graph or “DNA fingerprint” showing repeat numbers based on how much fluorescence is present.
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Cancer: the basicsCancer: the basics Uncontrolled cell growth Accumulation of mutations within genes Gradual development
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Cancer: the basics (cont.)Cancer: the basics (cont.) Proto-oncogenes Proteins formed from these genes maintain cell cycle and stop apoptosis Mutations within these genes form oncogenes (maintain cell cycle, always simulated, do not listen to signals or conditions to stop) Examples: ras gene, BRCA 1 oncogene (breast/ovarian cancer)
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Cancer: the basics (cont.)Cancer: the basics (cont.) Tumor suppressor genes -proteins formed from these genes prevent cell cycle and signal apoptosis -Prevent uncontrolled cell cycles and cell division with damaged DNA -Mutations within these genes cause the cell cycle to continue without control -Ex. Common ones seen in human cancer—RB, p53 genes for corresponding proteins
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What can cause mutations leading to cancer? Genetics/Heredity - certain individuals are more susceptible than others Viruses Environmental factors Chemicals Smoke UV/radiation exposure—skin cancer
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Cancer TerminologyCancer Terminology Cancer in situ– tumor at primary site Tumor: When cancerous cells divide, they form a mass of cancer cells within an otherwise normal tissue Benign tumor: Cancerous cells remain in one spot Growth does not continue Noncancerous Malignant tumor: Cancer cells become invasive enough to impair the functions of one or more organs Cancer cells have the ability to spread
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Cancer Cell Terminology (cont.) Metastasis: The spread of cancer cells beyond their original site -Cancer cells can break away from tumor to invade other locations throughout the body Angiogenesis: The process where cancer cells develop their own blood supply to obtain continued nutrients so they can keep growing. New blood vessels and the cancer cells use these to “fuel” their growth Treatments can fight this process
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How do we know a cell is cancerous?—Cancer Cell Traits 1) No differentiation -no function, abnormal appearance, unspecialized 2) Abnormal Nuclei -larger nucleus -abnormal chromosome numbers, more 3) No apoptosis -do not respond to signals from cell about abnormality or DNA damages -evade detection from the body’s immune system -do not die
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How do we know a cell is cancerous?—Cancer Cell Traits 4) No contact inhibition/ anchor -cancer cells do not “listen” to neighbors -continue to grow despite being crowded by neighbors—tumor results 5) Go through metastasis -break away from tumor and invade other cells throughout the body 6) Go through angiogenesis -create blood supply to provide nutrients for continued growth
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Normal v. Cancer CellsNormal v. Cancer Cells Have density-dependent inhibition Will only divide when attached to a substrate (anchored) Must have sufficient growth factors or nutrients for division Lack density-dependent inhibition Will divide in solution or when not anchored Unaffected by presence of external growth factors or nutrients
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