01 DNA

Structure

  • ribose backbone connected by phosphate group

  • 5' phosphate and 3' OH

  • during addition, 2 phosphate groups cut off. Monophosphate added to growing strains

Replication

  • origin of replication
  • DNA helicase: separates and unwinds, require ATP

  • 2 bonds at AT

  • major enzyme that makes new DNA

Primers

  • DNA polymerase requires primers
  • RNA polymerase does not require primer

Directionality

  • DNA polymerase break phosphate bond between 1 and 2 phosphate, creating energy needed to add nucleotide to DNA strand
  • phosphate bond on nucleotide can only go at 3' end where OH is

  • primer added to 3' end
  • nucleotides added to 3' end of primer in 5 to 3 direction

  • bottom strand in pieces

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Proofreading

  • DNA polymerase can move backwards using exonuclease activity

Telomerase

  • takes a piece of RNA and makes DNA that replaces telomere

  • TTAGG near 3'