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Where is DNA found within the cell?

Where is DNA found within the cell? . Quick Question #1. Lets refresh our knowledge of DNA structure http://www.youtube.com/watch?v=ZGHkHMoyC5I. What occurs during the cell cycle? . Quick Question #2. DNA REPLICATION. Copying of DNA An extremely precise process

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Where is DNA found within the cell?

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  1. Where is DNA found within the cell? Quick Question #1 Lets refresh our knowledge of DNA structure http://www.youtube.com/watch?v=ZGHkHMoyC5I

  2. What occurs during the cell cycle? Quick Question #2

  3. DNA REPLICATION • Copying of DNA • An extremely precise process • Copies in sections, not from one end to the other • Basis of biological inheritance

  4. Replication Process • Three step process • Each step controlled by one of three enzymes (enzymes always end in –aseso look out for them in these notes) • Directional: always starts at a 5’ end of DNA strands and builds onto the 3’ end: • Copies both strands simultaneously starting at the replication fork.

  5. What do you think needs to happen in order for replication to start Quick Question #3

  6. Replication: Step One Facilitated by: Helicase • Helicase enzyme unwinds and unzips DNA strands • breaks hydrogen bonds QQ#4 What do you think will needs to happen for the DNA to “unzip”?

  7. A G G C T C C G DNAPolymerase Replication: Step Two Facilitated by: DNA Polymerase • DNA Polymerase enzyme: • reads a base on one side • Then adds complementary (matching) base to the other • e.g.

  8. Step 2 Continued • Both sides replicated to create two new strands of DNA each with: • -One original and One new strand

  9. Step 2 Continued • Strands are replicated from 5’ to 3’ and go in opposite directions • One side is replicated in a continuous piece: • -Leading Strand • Other side is replicated in short pieces: • -Lagging Strand • Okazaki Fragments

  10. Replication: Step Three Facilitated by: Ligase • Ligase enzyme • Glues (ties) DNA all together • Very important for Okazaki Fragments-closes any gaps between them

  11. Draw a visual that helps YOU remember the 3 steps of replication Quick Question #5

  12. Overall Process of Replication http://www.youtube.com/watch?v=teV62zrm2P0

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