Thursday, December 6, 2012

December 6, 2012

DNA Replication.
Watch Video.
Helicase seperates DNA to create replication forks.
 Primase create a RNA Primer to create a starting point on the DNA for the Polymerase to start off of.
Polymerase move in a five to three direction. Making one DNA strand separated, RNase H removes the primers, allowing the Polymerase to replace the primer with a strand of DNA.
Polymerase fill in most of the of the gap. Then Ligase come and do the final connection between the DNA strands.
Rnase H aids DNA replication by degrading RNA bound to a DNA template

More detailed notes.


DNA Replication

The Helicase seprates the DNA strand
SSB(not on picture)- Single Strand Bindings Proteins. Hold the 2 strands apart until a new strand can be added.
RNA Primase- Apply a primer which gives a starting point for DNA polymerases. DNA polymerases can not start the process on their own and require a starting point. RNA Primase applies this.
The Difference between the leading strand and the lagging strand is that the Leading strand is one complete strand with one primer. While lagging strand has many primers and is in broken up strands and is not one complete strand.
Okazaki framents- The fragment that includes the primase with the new DNA on the Lagging strand stopping before next strand.
DNA polymerase- Attach onto a primer and adds new DNA nucleotides and an existing strand of DNA.
Rnase H- Removes the RNA Primers. Allowing DNA Polymerase to finish the strands.
Ligase- connects the fragments together

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