1.Briefly describe the process of DNA replication. 2.How fast are
10.4-10.5 Warm-Up 1.Briefly describe the process of DNA replication. 2.How fast are nucleotides added as your DNA replicates? 3.Describe a replication bubble. Why are numerous bubbles forming at once helpful? 4.What is DNA polymerase? DNA ligase? DNA replication depends on specific base pairing Section 10.4 DNA Replication A A Nucleotides Parental molecule of DNA Both parental strands serve as templates Enzymes use each strand as a template to assemble the new strands Two identical daughter molecules of DNA DNA Replication Untwisting and replication of DNA DNA replication: A closer look Section 10.5 Parental strand Origin of replication Daughter strand Bubble Two daughter DNA molecules DNA Replication Begins at Specific Sites 5ʹ′ end 3ʹ′ end P P P P P P P P Each strand of the double helix is oriented in the opposite direction DNA Polymerase • enzyme that links DNA nucleotides to a growing daughter strand • can only add to the 3’ end of parent strand • the new strand then grows in the 5’ to 3’ direction DNA Polymerase • proofreads new DNA strand (and fixes incorrect pairings) • can repair damaged DNA segments damage caused by radiation, ultraviolet light, toxic chemicals DNA polymerase 5ʹ′ end molecule 3ʹ′ 5ʹ′ Parental DNA 5ʹ′ 3ʹ′ Daughter strand synthesized in pieces 3ʹ′ 5ʹ′ P 3ʹ′ 5ʹ′ 5ʹ′ 3ʹ′ Daughter strand synthesized continuously P DNA ligase Overall direction of replication DNA daughter strands are synthesized 5’ to 3’ lagging strand 3ʹ′ 5ʹ′ DNA Ligase • enzyme that ties the together short pieces of DNA nucleotides into one single DNA strand (on lagging strand) • can repair damaged DNA damage caused by radiation, ultraviolet light, toxic chemicals Homework: • Packet Section 3,4 • Read 10.6-10.7
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