DNA Replication Professor M. J. Chorney MAGNET School for Medicine and Public Health, September 30, 2013
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