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DNA Replication

DNA Replication. Copying the genetic code. DNA Replication. Unpack the Chromosomes Unzip the DNA Base pairing at the replication fork Leading strand vs Lagging strand. Copying the genetic code. Making Copies. Making Copies. copied during cell division. copy.

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DNA Replication

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  1. DNA Replication Copying the genetic code

  2. DNA Replication • Unpack the Chromosomes • Unzip the DNA • Base pairing at the replication fork • Leading strand vs Lagging strand Copying the genetic code

  3. Making Copies

  4. Making Copies

  5. copied during cell division copy Sister Chromatids(identical copies)

  6. Accessing the DNA DNA in use inactive DNA (deactivated or mitotic)

  7. Visualization of DNA Packing • For this video, visit:http://www.hhmi.org/biointeractive/dna/DNAi_packaging_vo2.html

  8. Accessing the DNA

  9. Accessing the DNA

  10. DNA Structure

  11. Complementary Base Pairing

  12. Identical Parent and Daughter Strands

  13. Replication Bubbles 3’ 5’ 3’ 5’ helicase

  14. Replication Bubbles 3’ 5’ 3’ 5’

  15. Replication Bubbles 3’ 5’ 3’ 5’

  16. Replication Bubbles Replication Fork 3’ 5’ copies 3’ 5’ Replication Fork

  17. Replication Bubbles

  18. Releasing the Tension

  19. Releasing the Tension • Topoisomerase(gyrase) cleaves and uncoils DNA ahead of helicase • Single-stranded DNA binding proteins (SSB) prevent DNA from coiling back up

  20. DNA Replication Primase DNA Polymerase III 3’ 5’ RNA primer 3’ 5’

  21. DNA Replication • The leading strands grow toward the replication fork • PROBLEM: DNA polymerase III only works in the 5’-3’ direction. 3’ 5’ Leading Strands 3’ 5’

  22. DNA Replication 3’ 5’ 3’ 5’

  23. DNA Replication • The lagging strands grow away from the replication fork 3’ 5’ Lagging Strands 3’ 5’

  24. DNA Replication DNA Polymerase I DNA Ligase 3’ 5’ 3’ 5’

  25. DNA Replication 3’ 5’ 3’ 5’

  26. DNA Replicationcontinuous & discontinuous 3’ 5’ Okazaki Fragments 3’ 5’ DNA Polymerase moves in a 5’ - 3’ direction 5’-3’ chain synthesized continuously 3’-5’ chain synthesized discontinuously Results in a series of Okazaki fragments Later sealed up by DNA ligase

  27. The Whole Process in 3D • For this video, visit: • http://www.hhmi.org/biointeractive/dna/DNAi_replication_schematic.html

  28. The Whole Process in 3D • For this video, visit: http://www.hhmi.org/biointeractive/dna/DNAi_replication_vo2.html

  29. Animations • DNA Replication: • http://www.youtube.com/watch?v=4jtmOZaIvS0 • McGraw-Hill: DNA Replication & Meselson-Stahl: • http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter14/animations.html# • DNA Song: • http://www.youtube.com/watch?v=dIZpb93NYlw

  30. Credits • Molecule drawing created using ChemSketch. • Some from the Pearson or Nelson Biology 12 textbook. • Some images from Wikimedia Commons • Some from unknown sources.

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