S 1.2 Semi-discontinuous Replication Replication direction(exhibits polarity) The daughter strand is synthesized continuously in the 5'-3'direction. 3 5 3'← 5' 3 direction of unwinding ◆3' 5 No enzyme capable of synthesizing DNA in the 3'to 5'direction
§1.2 Semi-discontinuous Replication 5' 3' 3' 5' 5' direction of unwinding 3' * Replication direction(exhibits polarity) The daughter strand is synthesized continuously in the 5’-3’ direction. 5’ 3’ No enzyme capable of synthesizing DNA in the 3’ to 5’ direction
Experiment of Okazaki grow in 3H- thymidine medium for a proper time for a short time Inhibiting DNA ligase 3 4 前导链Leading strand ①①X 后随链Lagging strand wximwm而 movement of fork 冈崎片段 leading strand:the daughter strand is synthesized continuously in the 5'-3'direction. Okazaki fragments:Many DNA fragments are synthesized sequentially on the DNA template strand having the 5'-end.They are 1000-2000 nt long for prokaryotes and 100-200 nt long for eukaryotes. lagging strand:The daughter strand consisting of Okazaki fragments
Experiment of Okazaki grow in 3Hthymidine medium for a short time for a proper time Inhibiting DNA ligase leading strand: the daughter strand is synthesized continuously in the 5’-3’ direction. Okazaki fragments: Many DNA fragments are synthesized sequentially on the DNA template strand having the 5´- end. They are 1000 – 2000 nt long for prokaryotes and 100-200 nt long for eukaryotes. lagging strand:The daughter strand consisting of Okazaki fragments. Leading strand Lagging strand movement of fork
S 1.3 Bidirectional Replication replication fork 33 direction of fork movement direction of replication *Replication starts at a particular point (called origin),followed by the synthesis on each strand. *The parental dsDNA and two newly formed dsDNA form a Y-shape structure called replication fork
§1.3 Bidirectional Replication 3' 5' 5' 3' 5' 3' 5'3' direction of replication *Replication starts at a particular point (called origin), followed by the synthesis on each strand. *The parental dsDNA and two newly formed dsDNA form a Y-shape structure called replication fork. replication fork
Experiment of David M.Prescott and PeterL.Kuempel 低密度标记的DNA 高密度标记 0w0y0 高密度标记的DNA 的DNA Bidirectional Demonstration of bidirectional Replication replication by autoradiography forks Origin
Experiment of David M.Prescott and PeterL.Kuempel Demonstration of bidirectional replication by autoradiography
Replication of a circular chromosome in prokaryotes The replication process starts from the origin,and proceeds in two opposite directions.It is named 0 replication (0复制)
Replication of a circular chromosome in prokaryotes The replication process starts from the origin, and proceeds in two opposite directions. It is named replication (复制)