2.2 DNA replication

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Created by
Hattie Chew

Cards (6)

  • The experiment that investigated how DNA replicates is called the Meselon Stahl experiment. They used free nucleotides, made from light nitrogen and heavy nitrogen. They spun this in a centrifuge. The normal DNA (¹⁴N) was floating higher than the heavier DNA (¹⁵N).
  • The original structure of DNA is called the anti parallel double helix.
  • STEP 1 OF DNA REPLICATION:
    An enzyme (called DNA helicase) "unzips" the helix by breaking the hydrogen bonds between the complementary nitrogenous bases. This allows them to separate.
  • STEP 2 OF DNA REPLICATION:
    Free nucleotides (with specific bases) create hydrogen bonds with the complementary bases.
  • STEP 3 OF DNA REPLICATION:
    An enzyme called DNA polymerase makes phosphodiester bonds in condensation reactions, joining nucleotides together to make the phosphodiester backbone.
  • STEP 4 OF DNA REPLICATION: (kinda)
    We now have 2 new semi-conservative helixes. Both having 1 old strand and 1 new strand.