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SINTESIS DNA

SINTESIS DNA. REPLIKASI DNA. ALUR INFORMASI GENETIK. Flow of information. replication DNA  DNA transcription  RNA translation  protein. S.cerevisiae cell cycle. dsDNA. antiparallel. 5’. 3’. 3’. 5’.

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SINTESIS DNA

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  1. SINTESIS DNA REPLIKASI DNA

  2. ALUR INFORMASI GENETIK

  3. Flow of information replication DNA DNA transcription  RNA translation  protein

  4. S.cerevisiae cell cycle

  5. dsDNA antiparallel 5’ 3’ 3’ 5’ dsDNA is always antiparallel

  6. complementary Two ssDNA molecules joined by standard base-pairing rules In dsDNA, the strands are always complementary. 5’- -3’ GGATGCGT 3’-CCTACGCA-5’ TB

  7. Bacterial DNA replication DNA synthesis using a DNA template Complementary base pairing (A=T, GC) determines the sequence of the newly synthesized strand. DNA replication always proceeds from 5’ to 3’ end.

  8. REAKSI PERPANJANGAN

  9. Overview of bacterial DNA replication single origin (in bacteria) bidirectional theta structures replication fork semi-conservative TB

  10. bacterial DNA replication origin (start point) bidirectional bacterial chromosome

  11. theta structure two replication forks

  12. semi-conservative * * * + *

  13. Enzim yang terlibat dalam Replikasi SSB (ssDNA binding protein) Binds to and stabilizes ssDNA

  14. helicase Unwinds duplex DNA

  15. ssDNA binding protein binds to and stabilizes ssDNA prevents base pairing ssDNA binding protein

  16. Important facts All DNA polymerases require a primer DNA is synthesized 5' to 3' TB

  17. Template A sequence of DNA or RNA that directs the synthesis of a complementary sequence Primer • The initial segment of a polymer that is to be extended on which elongation depends

  18. primase synthesizes a short RNA primer using a DNA template primase RNA primer (a short starting sequence made of RNA) TB

  19. Polimerase Memerlukan primer dan cetakan DNA Polimerisasi diperpanjang pada 3’ Aktivitas eksonuklease 3’-5’, berfungsi sebagai proofreading Aktivitas eksonuklease 5’-3’ untuk menghilangkan primer

  20. DNA polymerase III Synthesizes DNA from a DNA template and proofreads DNA polymerase I Synthesizes DNA from a DNA template and removes RNA primers. TB

  21. DNA ligase Joins DNA strands together by forming phosphodiester bonds DNA ligase

  22. replication fork 5' lagging strand 3' 5' leading strand template strands 3'

  23. Leading strand synthesis 5' RNA primer helicase ssDNA binding proteins 3'

  24. 5' DNA polymerase helicase ssDNA binding proteins 3'

  25. Leading strand synthesis DNA 5' DNA pol III helicase 3' ssDNA binding proteins

  26. Lagging strand synthesis (discontinuous) Okazaki fragment (~1000 bases) 3' pol III (primase) 5' helicase ssDNA binding proteins 3'

  27. Primer removal pol III 3' 5' pol I 5’ to 3’ exonuclease activity pol I

  28. Proofreading

  29. Proofreading Pol III removes misincorporated bases using 3' to 5' exonuclease activity This decreases the error rate to about 10-10 per base pair inserted

  30. Ligase DNA Menyambung dua fragmen Okasaki dengan membentuk ikatan fosfodiester antara 3’-OH fragmen 1 dengan 5’-P fragmen 2

  31. Ligation DNA ligase

  32. KEPERLUAN REPLIKASI DNA TEMPLATE (CETAKAN) PRIMER : 3’-OH - PERPANJANGAN PREKURSOR : dNTP Enzim : polimerase DNA, helikase, primase, SSBP, ligase

  33. 5 3 5

  34. Lokus awal replikasi (Ori)

  35. INISIASI

  36. Prokaryotic vs. Eukaryotic Bacterial cells have one giant looped chromosome Replication can occur in one or two directions Oneorigin of replication In Eukaryotes manyorigins of replication exist These form replication bubbles Eventually bubbles meet and replication is done Replication forks - where DNA is opened up

  37. REPLIKON E.coli

  38. REPLIKON MAMALIA

  39. Replication of the ends of linear DNA newly synthesized DNA RNA primer 3' 5' template Since all known DNA polymerases need a primer, how are the ends of linear DNA replicated in eukaryotes?

  40. Example GGGGTT GGGGTT GGGGTT (GGGGTT)n n = 20 - 200 Telomeres repetitive DNA at the end of linear eukaryotic chromosomes 5'

  41. AACCCCAAC telomerase Telomerases are enzymes that add DNA repeats to the 3' end of DNA. Telomerases are composed of protein and an RNA molecule that functions as the template for telomere synthesis.

  42. Human telomerase Telomerase = ribonucleoprotein complex Ribo = ribosomal/RNA association Nucleo = nuclear localization Protein = contains a protein Responsible for maintaining telomere length in eukaryotic chromosomes Main components: Telomerase reverse transcriptase Human telomerase RNA (hTR)

  43. Human telomerase (2) Reverse transcriptase Transcribes RNA to DNA (rather than the usual DNA to RNA) Telomeres – repeated regions at the end of eukaryotic chromosomes hTR is the template for the repeated region

  44. Human telomerase (3) hTR 11-nt templating region consists of: Repeat template: CUAACCC Alignment domain: UAAC Positions telomerase on the DNA strand Provides template for repeat region

  45. GGGGTT 5' AACCCCAAC GGGGTT 5' telomerase

  46. AACCCCAAC GGGGTT GGGGTT GGGGTT GGGGTT GGGGTT GGGGTT 5' primase 5'

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