SectionF-課件.ppt

1、Molecular biology course，section f DNA damage，repair，and recombination，link，f1 mutagenesis(突變觸發(fā))，DNA damagePhoto reaction、alkyl transferase、excision repair、mismatch repair、hereditary repair defects、homologous recombination reasons spontaneous errors in DNA replication or meiotic recombination a cons

2、equence of the damaging effects of physical or chemical muta gens on dnns noncoding(非編碼)DNA Nonregulatory(非協(xié)調(diào))DNA 3rd position of a codon(密碼子)，silent mutory Missense mutation無(wú)效語(yǔ)義突變，phennen the addition or loss of one or more bases in a DNA region，f1 mutaagenesis，examples of deletion mutations，F(xiàn)1-2 r

3、eplication fidionRNA priming(啟動(dòng)): proofreading to Smatch repair(F3)(修復(fù)不一致)，f1 mutagenesis，by E.coli polymerase，pro ofrefrence物理突變high-energy ionizing radiation : x-rays and g-rays strand breaks and Base/Sugar destruction none，nitrous acid 3360 deaminates c to produce u，resulting in GC，au，direct muta

4、genesis(但是DNA也具有穩(wěn)定、更改的配對(duì)屬性的未修復(fù)堿，牙齒損壞固定在永久突變狀態(tài)下例如，堿T的類(lèi)似物5-溴尿布的酮基異構(gòu)體預(yù)計(jì)與A配對(duì)，經(jīng)常與乙醇G配對(duì)。f1 mutaagenesis，5-bru，g，a，enol form，oh，h，o，atgc transition，f1 mutagenes但是有時(shí)，由于破壞的堿基經(jīng)常丟失特殊的堿基對(duì)，一些受損的DNA聚合酶被稱(chēng)為間接突變誘發(fā)，以確保染色體的完整性損傷在該部位插入錯(cuò)誤的堿基。例如：細(xì)菌的SOS反應(yīng)容易修復(fù)錯(cuò)誤。f1 mutaagenesis、DNA damage and repair、mu tagen(突變物質(zhì))、complete

5、ly repaired、DNA damage (lesions)和chemicis Uv光(Physical mutagens)carcinogen(chemical mutagens)、DNA damage、repair recombination、DNA damage An inherent chemical reactivity of the DNA the presence of normal，reactive chemical species within the cell，Deamination 333 the level of this damage can be increeased by hydroxyl radicals from the radiolysis of H2O caused by ionizing radiation，DNA damage，DNA damage.Alkyl ating agents，DNA damage，repair