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Published byIsaac Terry Modified over 9 years ago
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DNA Replication Copying the genetic code
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DNA Replication Unpack the Chromosomes Unzip the DNA Base pairing at the replication fork Leading strand vs Lagging strand
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Making Copies
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copycopied during cell division Sister Chromatids (identical copies)
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Accessing the DNA inactive DNA (deactivated or mitotic) DNA in use
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Visualization of DNA Packing For this video, visit: http://www.hhmi.org/biointeractive/dna /DNAi_packaging_vo2.html http://www.hhmi.org/biointeractive/dna /DNAi_packaging_vo2.html http://www.hhmi.org/biointeractive/dna /DNAi_packaging_vo2.html
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Accessing the DNA
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DNA Structure
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Complementary Base Pairing
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Identical Parent and Daughter Strands
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Replication Bubbles helicase 5’ 3’ 5’
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Replication Bubbles 5’ 3’ 5’
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Replication Bubbles 5’ 3’ 5’
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Replication Bubbles copies Replication Fork 5’ 3’ 5’
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Replication Bubbles
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Releasing the Tension
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Topoisomerase (gyrase) cleaves and uncoils DNA ahead of helicase Single-stranded DNA binding proteins (SSB) prevent DNA from coiling back up
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DNA Replication Primase RNA primer DNA Polymerase III 5’ 3’ 5’
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DNA Replication The leading strands grow toward the replication fork PROBLEM: DNA polymerase III only works in the 5’-3’ direction. Leading Strands 5’ 3’ 5’
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DNA Replication 5’ 3’ 5’
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DNA Replication Lagging Strands The lagging strands grow away from the replication fork 5’ 3’ 5’
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DNA Replication 5’ 3’ 5’ DNA Polymerase I DNA Ligase
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DNA Replication 5’ 3’ 5’
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DNA Replication continuous & discontinuous Okazaki Fragments 5’ 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
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The Whole Process in 3D For this video, visit: http://www.hhmi.org/biointeractive/dna /DNAi_replication_schematic.html http://www.hhmi.org/biointeractive/dna /DNAi_replication_schematic.html http://www.hhmi.org/biointeractive/dna /DNAi_replication_schematic.html
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The Whole Process in 3D For this video, visit: http://www.hhmi.org/biointeractive/dna/ DNAi_replication_vo2.html http://www.hhmi.org/biointeractive/dna/ DNAi_replication_vo2.html
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Animations DNA Replication: http://www.youtube.com/watch?v=4jtmOZaIvS0 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# http://highered.mcgraw- hill.com/sites/0072437316/student_view0/chapter14/ animations.html# http://highered.mcgraw- hill.com/sites/0072437316/student_view0/chapter14/ animations.html# DNA Song: http://www.youtube.com/watch?v=dIZpb93NYlw http://www.youtube.com/watch?v=dIZpb93NYlw
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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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