Semi-conservative

• What is semi-conservative replication?

  -DNA strands are separated

  -each strand is replicated separately to produce DNA that is half newly synthesised and half parental

  -results in 2 hybrid DNA molecules
• What is the first step of semi-conservative replication?

  DNA helicase unwinds the double helix and separates the two strands by breaking hydrogen bonds that hold the complementary base pairs together.
• What is the second step of semi-conservative replication?

  RNA primase adds complementary base pairs as an RNA primer to the leading strand, with the original DNA strand acting as a template for the complementary base pairs on the free RNA nucleotides.
• What is the third step of semi-conservative replication?

  DNA polymerase synthesises DNA molecules from the RNA primer nucleotide building blocks on the leading strand
• What is the forth step of semi-conservative replication?

  RNA primase adds RNA primers at different places along the lagging strand.
• What is the fifth step of semi-conservative replication?

  DNA polymerase adds DNA nucleotides in the 5' to 3' direction on the lagging strand and replaces all the RNA nucleotides from the RNA primers with DNA nucleotides.
• What is the last step of semi-conservative replication?

  DNA ligase joins all the fragments together.