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