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In this chapter, the following content will be discussed: DNA replication is semiconservative, general features of DNA replication, DNA polymerases, the mechanism of DNA replication, eukaryotic DNA replication, telomeres and telemerases, reverse transcriptase, DNA repair. | Chapter 30 DNA Replication and Repair to accompany Biochemistry, 2/e by Reginald Garrett and Charles Grisham All rights reserved. Requests for permission to make copies of any part of the work should be mailed to: Permissions Department, Harcourt Brace & Company, 6277 Sea Harbor Drive, Orlando, Florida 32887-6777 1 Outline 30.1 DNA Replication is Semiconservative 30.2 General Features of DNA Replication 30.3 DNA Polymerases 30.4 The Mechanism of DNA Replication 30.5 Eukaryotic DNA Replication 30.6 Telomeres and Telemerases 30.7 Reverse Transcriptase 30.8 DNA Repair 2 The Dawn of Molecular Biology April 25, 1953 Watson and Crick: "It has not escaped our notice that the specific (base) pairing we have postulated immediately suggests a possible copying mechanism for the genetic material." The mechanism: Strand separation, followed by copying of each strand. Each separated strand acts as a template for the synthesis of a new complementary strand. 3 DNA Replication The Semiconservative Model Matthew Meselson and Franklin Stahl showed that DNA replication results in new DNA duplex molecules in which one strand is from the parent duplex and the other is completely new Study Figure 30.4 and understand the density profiles from ultracentrifugation experiments Imagine and predict the density profiles that the conservative and dispersive models would show 4 Features of DNA Replication DNA replication is bidirectional Bidirectional replication involves two replication forks, which move in opposite directions DNA replication is semidiscontinuous The leading strand copies continuously The lagging strand copies in segments (Okazaki fragments) which must be joined The Enzymology of DNA Replication If Watson and Crick were right, then there should be an enzyme that makes DNA copies from a DNA template In 1957, Arthur Kornberg and colleagues demonstrated the existence of a DNA polymerase - DNA polymerase I Pol I needs all four deoxynucleotides, a template and a primer - a ss-DNA . | Chapter 30 DNA Replication and Repair to accompany Biochemistry, 2/e by Reginald Garrett and Charles Grisham All rights reserved. Requests for permission to make copies of any part of the work should be mailed to: Permissions Department, Harcourt Brace & Company, 6277 Sea Harbor Drive, Orlando, Florida 32887-6777 1 Outline 30.1 DNA Replication is Semiconservative 30.2 General Features of DNA Replication 30.3 DNA Polymerases 30.4 The Mechanism of DNA Replication 30.5 Eukaryotic DNA Replication 30.6 Telomeres and Telemerases 30.7 Reverse Transcriptase 30.8 DNA Repair 2 The Dawn of Molecular Biology April 25, 1953 Watson and Crick: "It has not escaped our notice that the specific (base) pairing we have postulated immediately suggests a possible copying mechanism for the genetic material." The mechanism: Strand separation, followed by copying of each strand. Each separated strand acts as a template for the synthesis of a new complementary strand. 3 DNA Replication The Semiconservative .
