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DNA replication Central dogma of molecular biology.

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Presentation on theme: "DNA replication Central dogma of molecular biology."— Presentation transcript:

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2 DNA replication Central dogma of molecular biology

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4 1.the basic principle of DNA replication (1) Semiconservative replication

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6 a. concept b. evidence c. conclusion

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8 (2) Semidiscontinuous replication * The synthesis direction of DNA polymerase * leading strand & lagging strand

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10 * Okazaki fragment (3) RNA primer * the synthesis * the function

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12 (4) fidelity 2. Enzymes & proteins cooperate in the DNA replication

13 (1) E.coli DNA polymerase I (Kornberg enzyme,DNA-Directed DNA polymerase,DDDP,pol I )

14 * The principle materials for pol I # four dNTP # Mg 2+ # RNA primer or DNA single strand possessed 3’-OH # DNA template

15 * Multiple function of pol I Klenow fragment------- (large fragment) DNA polymerase activity, 3’-5’ exonuclease activity small fragment------- 5’-3’ exonuclease activity

16 5’ 3’ 3’ 5’ exonuclease exonuclease DNA polymerase activity activity activity Small fragment large fragment (Klenow fragment) pol I Proofreading

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19 * the principle materials for pol II & pol III # four dNTP # Mg 2+ # RNA primer or DNA single strand possessed 3’-OH # DNA template

20 * the characteristics of pol II & pol III pol II---mostly concerned with proofreading & DNA repair pol III---- indispensable for DNA replication,the highest rate of chain elongation and processive

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23 (2) DNA polymerase in eukaryocyte polymerase  : gap filling & synthesis of lagging strand  : DNA proofreading & repair  : DNA repair  : mitochondria DNA synthesis  : processive,leading strand synthesis, need the assistance of PCNA

24 (3) helicase & gyrase a. helicase * function * require b. single strand binding protein (SSB),helix disabling protein,HDP

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26 * function c.topoisomerase I * function d. topoisomerase II, gyrase * function

27 (4) Primosome (5) DNA ligase * function * require * process

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30 * characteristics * usage 3.procedure of DNA replication (1) the initiation of the replication

31 * the origin of replication ---- The special structure (ori C) * the process of initiation formation of replication fork ( replication bubbles)

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34 * how to deal with synthesis direct ? (3) the termination of the replication (2) the elongation of the replication

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41 *Removes primers---- pol I small fragment * fills the gap with dNTP----- pol I large fragment (Klenow fragment) * ligation----DNAligase

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44 4. Summarize of DNA replication a.identification of the origin of replication b.unwinding (denature)of ds DNA to provide ssDNA c. formation of replication fork d.initiation of DNA synthesis & elongation

45 e. formation of replication bubbles with ligation of the newly synthesized DNA segment f. Reconstitution of chromatin DNA

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49 5.Telomere & telomerase (1) telomere *concept *structure * function

50 (2) The function & molecular components of telomerase * function * components (RNP) * mechanism

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53 Telomerase & carcinoma 5.DNA damage & repair (1) the basic of repair (2)the causes of DNA damage *remove purine by heat & acid

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55 ionizing radiation ultraviolet ray chemical agents (3) The type of DNA damage

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57 (4)Mechanism of DNA repair * photo repair * excision repair significant (correct large defects) * base excision repair a.process

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64 Characteristics summarize a. the enzyme uracil DNA glycosylase removes the uracil created by spontaneous deamination of cytosine

65 b. an endonuclease cuts the backbone near the defect c. an endonuclease removes a few bases d. the defect is filled in by the action of a repair polymerase ( pol I )

66 e. The strand is rejoined by ligase


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