SectionF-课件.ppt

1、Molecular biology course，section f DNA damage，repair，and recombination，link，f1 mutagenesis(突变触发)，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(非编码)DNA Nonregulatory(非协调)DNA 3rd position of a codon(密码子)，silent mutory Missense mutation无效语义突变，phennen the addition or loss of one or more bases in a DNA region，f1 mutaagenesis，examples of deletion mutations，F1-2 r

3、eplication fidionRNA priming(启动): proofreading to Smatch repair(F3)(修复不一致)，f1 mutagenesis，by E.coli polymerase，pro ofrefrence物理突变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也具有稳定、更改的配对属性的未修复碱，牙齿损坏固定在永久突变状态下例如，碱T的类似物5-溴尿布的酮基异构体预计与A配对，经常与乙醇G配对。f1 mutaagenesis，5-bru，g，a，enol form，oh，h，o，atgc transition，f1 mutagenes但是有时，由于破坏的碱基经常丢失特殊的碱基对，一些受损的DNA聚合酶被称为间接突变诱发，以确保染色体的完整性损伤在该部位插入错误的碱基。例如：细菌的SOS反应容易修复错误。f1 mutaagenesis、DNA damage and repair、mu tagen(突变物质)、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