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Chapter 12 Topics

Chapter 12 Topics. Models of Replication Prokaryotic and Eukaryotic Replication Models of Recombination: read pp 339-342. Three Models of DNA Replication Which is correct?. http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter14/animations.html#.

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Chapter 12 Topics

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  1. Chapter 12Topics Models of Replication Prokaryotic and Eukaryotic Replication Models of Recombination: read pp 339-342

  2. Three Models of DNA Replication Which is correct? http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter14/animations.html#

  3. DATA TO SUPPORT SEMI-CONSERVATIVE MODEL

  4. Prokaryotic Replication E.coli 4.7 million bp Bacteria can double every 20 minutes at a rate of 1000 nucleotides/second!

  5. 2 models of Prokaryotic Replication The Theta Model Rolling Pin Model • θ

  6. Theta Replication Radioactive labeled prokaryotic DNA

  7. Rolling Pin Model Occurs in viruses and factor F

  8. Prokaryotic Mechanism of Replication An: overview of E. coli replication

  9. Bacterial Mechanism of Replication oriC Key concepts & Proteins Step 1. Initiation Step 2. Unwinding: Helicase helicases

  10. Disease of Aging: Werner’s Disease In eukaryotic cells: helicase mutation has been related to “Werner’s Disease.

  11. Notice: Directionality Notice:Replication Bubble Forms Helper proteins Helper proteins

  12. SUMMARY Prokaryotic DNA replication Leading strand Lagging strand

  13. Prokaryotes Polymerases The major players are: • Pol l • Pol II • Pol III • Pol IV • Pol V Removes/replaces primers repair ELONGATION: step 4 repair

  14. Step 5. Ligation These darn Okazaki Fragments! • Ligase

  15. Step 6. Termination • A certain DNA sequence may replication • Aprotein may physically replication

  16. SUMMARY Prokaryotic DNA replication Leading strand Lagging strand

  17. http://www.johnkyrk.com/DNAreplication.html Animation of Elongation Nucleotide polymerization http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter14/animations.html#

  18. How are mistakes avoided? • By: Nucleotide selection • By: Proofreading • By: Mismatch Repair

  19. Fidelity of DNA replication • Only 1 mistake per billion nucleotides!

  20. Eukaryotic Replication A human chromosome about 100 million bp Replication occurs in minutes to hours!

  21. Can you notice a difference between this replication process vs bacterial replication? Answer: Numerous replication origins.

  22. 5’ to 3’ replication occurs in eukaryotes just like in our bacterial friends.

  23. Prokaryotic and Eukaryotic Replication are similar but there are some differences; these include…

  24. Origins “get tagged” by a replication licensing factor.

  25. DNA Pol α DNA polδ DNA pol β DNA pol ε DNA pol γ Priming & replication (RNA polymerase) Replication Repair & recombination Repair and replication Mitochondrial DNA replication Eukaryotic DNA Polymerases There are more and different DNA polymerases.

  26. Nucleosome Assembly Unique to eukaryotic replication process

  27. What happens when you reach the end of linear DNA?

  28. Oops a problem at the end!! http://faculty.plattsburgh.edu/donald.slish/Telomerase.html

  29. Telomeres and Telomerase! Are loss of telomeres related to aging?

  30. Or is too much telomerase activity related cancer?

  31. Cells with telomerase activity Embryonic cells Intestinal cells And bone marrow

  32. Assignment please read: pp 335-339 The Holliday Model of DNA recombination

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