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TRANSCRIPT
DNA Replication
Professor M. J. Chorney
MAGNET School for Medicine and
Public Health, September 30, 2013
Figure 4-3 Molecular Biology of the Cell (© Garland Science 2008)
Review
Figure 4-4 Molecular Biology of the Cell (© Garland Science 2008)
Review
Figure 4-5 Molecular Biology of the Cell (© Garland Science 2008)
Review
Figure 5-2 Molecular Biology of the Cell (© Garland Science 2008)
DNA serves as a template for its own synthesis-semiconservative
replication
Figure 5-5 Molecular Biology of the Cell (© Garland Science 2008)
Figure 5-3 Molecular Biology of the Cell (© Garland Science 2008)
The all important
site for extension
Figure 5-4 Molecular Biology of the Cell (© Garland Science 2008)
DNA Polymerase Simulation and Model
Figure 5-9 Molecular Biology of the Cell (© Garland Science 2008)
The pol has exonuclease activity which we previously talked
About, involved in mismatch repair, called more specifically
Proofreading/Editing
Table 5-1 Molecular Biology of the Cell (© Garland Science 2008)
Figure 5-7 Molecular Biology of the Cell (© Garland Science 2008)
DNA polymerase requires a PRIMER WHICH IS MADE
FROM RNA BY RNA PRIMASE!!! BOTH STRANDS
THE PRIMERS ARE EVENTUALLY REMOVED
Figure 5-12 Molecular Biology of the Cell (© Garland Science 2008)
Figure 5-11 Molecular Biology of the Cell (© Garland Science 2008)
No
primer
required
for RNA primase
Figure 5-10 Molecular Biology of the Cell (© Garland Science 2008)
For Advanced
Consideration
Why doesn’t
DNA extend
from the 5’
end?
It has to do
with phosphates
and proofreading
Figure 5-19a Molecular Biology of the Cell (© Garland Science 2008)
Figure 5-19b,c Molecular Biology of the Cell (© Garland Science 2008)
Figure 5-25 Molecular Biology of the Cell (© Garland Science 2008)
Figure 5-44 Molecular Biology of the Cell (© Garland Science 2008)
Review Green arrow, methylation sites
Blue arrow, hydrolytic cleavage
Red arrow, oxidation
Figure 5-45 Molecular Biology of the Cell (© Garland Science 2008)
Two examples, review
Figure 5-46 Molecular Biology of the Cell (© Garland Science 2008)
Thymine
dimers
Figure 5-47 Molecular Biology of the Cell (© Garland Science 2008)
Changes can give rise to mutations
Figure 5-48 Molecular Biology of the Cell (© Garland Science 2008)
Figure 5-49 Molecular Biology of the Cell (© Garland Science 2008)
The glycosylase would cleave out the base
Note the helix
distortion
Figure 5-50a Molecular Biology of the Cell (© Garland Science 2008)
Thymine has no amino group
Explain:
1.5’-3’ and its relevance to strand synthesis
2.RNA primase activity
3.Okazaki fragments
4.Proofreading
5.Helicase
6.Leading versus lagging strand synthesis
7.Semiconservative replication of dna
8.The replication fork, replication bubble