Set 11: DNA Replication Goes through two steps initiation and elongation, roles of enzymes, telomeres and cancer.
16 Oct 2011
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Set 11: DNA Replication
Feb 16, 2011
The Watson Crick Model of DNA Replication:
DNA replication is semi-conservative
new double helix consists of one parent strand and one
daughter strand
1958: Meselson and Stahl (remember these names)
performed studies with isotopic composition of
nucleotides incorporated into daughter DNA strands
Two Steps of DNA Replication:
1. Initiation
region of As and Ts (two H bonds, easier to break)
Initiator protein binds at fork
DNA helicase pulls strands apart and unwinds them
Single Stranded Binding Proteins bind to bubble, and
keep it open so that enzymes can come in
DNA primase – bring in RNA primers so polymerase has
something to add on to
Feb 14, 2011
2. Elongation / Replication
DNA Polymerase III adds nucleotides
** DNA Polymerase needs a 3’ hydroxyl to add nucleotides to
RNA primers removed by Polymerase I
Polymerase I then fills in gaps