1 / 11

LEQ: How does DNA make a copy of itself?

LEQ: How does DNA make a copy of itself?. 10.4 and 10.5. DNA Replication?. DNA replication: DNA making DNA Why must DNA replicate? So that when a cell divides, each new cell gets a copy of the DNA When does DNA replication take place? During the S phase of interphase

janine
Download Presentation

LEQ: How does DNA make a copy of itself?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. LEQ: How does DNA make a copy of itself? 10.4 and 10.5

  2. DNA Replication? • DNA replication: DNA making DNA • Why must DNA replicate? • So that when a cell divides, each new cell gets a copy of the DNA • When does DNA replication take place? • During the S phase of interphase • When chromosomes go from individual chromosomes to double chromosomes

  3. Semi-conservative Replication • DNA replication where the replicated DNA consists of one old strand and one newly made strand

  4. DNA Replication • Origin of replication • Sites where replication of DNA begin • Replication fork/bubbles • Openings in DNA where replication takes place

  5. DNA Replication

  6. DNA Replication • Occurs in the Nucleus 1. Helicase binds to the origin of replication to unwind and unzip DNA; Breaking what bond? • Hydrogen Bonds – helicase breaks hydrogen bonds 2. DNA polymerase brings in complementary nucleotides attaching them in a 5’ to 3’ direction (phosphate of new incoming nucleotide attaches to the 3’ last nucleotide in the strand

  7. DNA Replication 3. Ligase– joins sugars and phosphates of newly formed strands of DNA 4. DNA polymerase – proofreads DNA, checking of spelling errors • Replication ends with 2 identical molecules of DNA; each with 1 old strand and 1 new stand

  8. DNA Replication

  9. DNA Replication • Direction of Replication • 5’ to 3’ – DNA polymerase needs to have an open 3’ carbon on deoxyribose so that it can add a new nucleotide • Leading vs Lagging • Leading strand is “continuously” replicated into the the replication fork runs 5’ to 3’ • Lagging strand is “discountinuosly” replicated; out of the replication fork runs 3’ to 5’

  10. DNA Replication • Okazaki Fragments - short stretches of nucleotides formed on the lagging strand of DNA • Why do we need Okazaki Fragments? • They are needed to get replication going in the correct direction on the lagging strand

  11. http://sites.fas.harvard.edu/~biotext/animations/replication1.htmlhttp://sites.fas.harvard.edu/~biotext/animations/replication1.html DNA replication Interactive You should be aware of the function of Helicase, DNA polymerases, and Ligase

More Related