DNA Replication Flashcards
what is the goal of DNA replication?
semiconservative; create exact copy using a template (cheat sheet)
who are the “workers” for DNA replication?
DNA helicase, DNA ligase, RNA primase, DNA POL I, DNA POL III
- Fast/hard worker (500-1000 nucleotides/second
- poor starter/great follower: needs RNA primers
- occasionally makes mistakes
- identify and fix mistakes (proof reading exonuclease function)
DNA POL III (younger)
- slow & “lags” behind POL III, but makes fewer mistakes
- poor follower/ great starter
DNA POL I (older)
removes RNA primers & replaces with DNA nucleotides
POL. I
- needs clear direction (template)
- focused (works 5’ to 3’; adds nucleotides to 3’ end only)
DNA POL. I & III
synthesized in pieces; discontinuous
lagging strand
continuously synthesized
leading strand
DNA helicase breaks hydrogen bonds at the replication origin to form replication forks
step I DNA replication
complementary RNA primers bind to DNA (RNA primase)
Step II DNA replication
DNA POL III adds complementary DNA nucleotides to 3’ end of RNA primer
Step III DNA replication
DNA POL I removes RNA primers & replaces with complementary DNA nucleotides
Step IV DNA replication
DNA ligase binds all DNA pieces to create 2 continuous new strands
Step V DNA replication