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32 Cards in this Set
- Front
- Back
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carcinogens bind _____ to DNA helix
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covalently
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DNA damage can be either _____ or ____
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direct(carcinogen binds and modifies)
indirect(free radicals created that then modify) |
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what is a hot spot and are they bad
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area where there is an increased number of mutations in DNA sequence
depends on if they have consequences maybe not |
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extra base inserted into dna causing different amino acids added is what mutation
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frameshift
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mispairing and a change in aa inserted is what mutation
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base substitution
not big deal unless in important protein coding region (get altered protein) |
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looking at things we know are mutagens and comparing to structures f sample compounds is what type of test
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structure activity analysis test
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Describe ames test
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modify bacteria so that they die with NO histadine
plate them with the mutagen chemical/liver activating enzyme/agar put on histadine plate but not enough that colonies form if colonies do form then the bacterias have mutated to live without histadine more colonies more mutagenesis |
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revertant colonies are
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colonies that have reverted back to wild type thru mutagenesis
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DNA repair pathways (4)
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nucleotide excision
mismatch base excision recombination |
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xeroderma pigmentosum
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NER deficiency
genetic disorder |
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whats faster/more efficiant repairing DNA or transcribed DNA
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transcribed
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cyclophosphamide-treated rats sperm may cause
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embryo death or abnormalities
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aflatoxin
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mutagen from moldy food
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mechanism of mutation (3 steps/events)
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initiation: application of agent
promotion: increased dna synthesis,etc progression/proliferation: more genetic events |
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procarcinogens need to be ____ to be activated
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metabolized
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Ha-Ras is the
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oncogene for cellular growth
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a complete carcinogen
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causes initiation and promotion (also a mutagen)
if not mutagen then not compplete but still has role |
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gene repression,activation,depression
stimulation of cell division clonal expansion are effects of... |
epigenetic carcinogens
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gene mutation
dna modification mitotic recommendation chromosomal aberrations are effects of... |
genetic carcinogens
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tumorigenic compound in tobacco
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polycyclic aromatic hydrocarbon
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nitrosamine is a..
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PAH
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explain benzo[a]pyrene effects on body
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its a PAH that doesnt bind to DNA or affect it. But the CYP450 enzymes metabolize into epoxide thats then converted by epoxide hydrolase into diols.
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Diols..
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form DNA adducts(bad)/can be conjugated into something inactive(good)
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NNK
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nicotine derived nitrosamine ketone that is metabolized by cyp450 and makes dna adducts
found in hair,newborns,etc |
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cyp1A1
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makes active carcinogenic epoxide from benzo[a]pyrene
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AhR
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aryl hydrocarbon receptor which PAH binds to
steroid receptor interacts with HSP,once bound goes into nucleus and turns on gene expression (like cyp1A1) |
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tumor supressor genes can be inactivated by...
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carcinogens
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proto oncogene is ____ mutation
oncogene is _____ mutation |
before
after |
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c-Ha ras
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regulates p21 for cell cycle regulation
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tumor suppressor genes
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arrest the cell cycle and allow for time to repair
also regulate cell death |
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p53
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tumor suppressor gene
mutated in many cancer therefore doesnt carry of suppressor functions |
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oltipraz
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decreases # of damaged cells and causes cell death to changed cells. specifically it induces glutathione trransferase that detoxify alfatoxin
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