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16 Cards in this Set
- Front
- Back
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What 2 types are cyclins/Cdks involved in the cell cycle?
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- going from G1 to S
- going from G2 to M |
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What happens with cyclins/Cdks before S?
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- cyclins accumlate and bind to specific Cdks
- Cdks phosphorylate proteins for DNA synthesis - Cdks degrade |
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What happens with cyclins/Cdks before M?
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- cyclin accumlates and activate specific Cdks
- Cdk is phosphorylates which does 1) phosphorylate lamins to breakdown nuclear envelope 2) phosphorylate microtubles (mitotic spindle) 3) phosphorylate histone H1 (chromosome condensation) 4) activates enzyme to degrade cyclin |
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What are the roles of p53 and Rb?
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- tumor supressor genes
- control cell cycle |
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What happens in patients with ataxia telangiectasia?
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- defective in DNA damage-induced block to the cell cycle
- immunodeficient (T/B cells require DNA rearrangement ot become differentiated) - high cancer incidence as DNA not repaired - very sensitive to X-rays |
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What do telomeres do?
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- prevent chromosome erosion
- prevent cell cycle arrest/apoptosis |
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What does telomerase do (generally)
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- adds TTAGGG to the ends of chromosomes
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How does telomerase add DNA?
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- reverse transcriptase
- catalyzes cycles of short additions of DNA to the end of chromosomes - DNA polymerase than adds in the intermediate area to where the last 5' okazaki fragment is |
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Do germ line cells/somatic tissue cells express telomerase activity?
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- germ line: yes, so that they continually maintain correct telomere length
- somatic: no, b/c most are not dividing |
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What is Dyskeratosis congenita (DKC)?
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- dramatically shortened telomeres
- mutation in TERC, RNA component of telomerase OR mutation in protein genes for telomerase - mortality from progressive bone marrow failure - defects in skin, hair, nails, epitheli, lung tx - primarily affect tissues with high turn over |
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How does acyclovir work?
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- structural analog of deoxyguanosine
- targets herpes virus - virus incorporates the drug into DNA - cell cycle fails b/c drug does not have a free 5' OH to allow DNA synthesis |
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What do AZT and dideoxynucleosides inhibit viruses?
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- incorporated during DNA replication and cause premature chain termination
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Tenofovir is used to treat which virus?
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- HIV
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How does Tenofovir work?
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- inhibits the activity of HIV reverse transcriptase by DNA chain termination
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Camptothecin is specific for? What does this do?
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- topoisomerase I
- inhibits DNA synthesis by trapping the covalent DNA-topo I intermediate |
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Daunomycin, adreiamycin, ellipticine, actinomycin D, m-AMSA, VM-26 are what kind of drugs? how do they work?
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- anti-topo II drugs
- trap the topo II-DNA covalent intermediate |
