Figure: 18-01 Title: The replisome assembles at the origin Caption: Replication initiates when a protein complex binds to the origin and melts the DNA there. Then the components of the replisome, including DNA polymerase, assemble. The replisome moves along DNA, synthesizing both new strands.

Figure: 18-02 Title: Each parental strand of DNA is a template Caption: Semiconservative replication synthesizes two new strands of DNA.

Figure: 18-03 Title: Repair synthesis replaces a short stretch of DNA Caption: Repair synthesis replaces a short stretch of one strand of DNA containing a damaged base.

Figure: 18-04 Title: Nucleic acid synthesis proceeds from 5' to 3' Caption: DNA is synthesized by adding nucleotides to the 3' - OH end of the growing chain, so that the new chain grows in the 5’ –> 3' direction. The precursor for DNA synthesis is a nucleoside triphosphate, which loses the terminal two phosphate groups in the reaction.

Proofreading function Figure: 18-05 Title: DNA polymerases have exonuclease activity Caption: Bacterial DNA polymerases scrutinize the base pair at the end of the growing chain and excise the nucleotide added in the case of a misfit. Proofreading function

Figure: 18-06 Title: DNA polymerases have a common structure Caption: The common organization of DNA polymerases has a palm that contains the catalytic site, fingers that position the template, a thumb that binds DNA and is important in processivity, an exonuclease domain with its own active site, and an N-terminal domain.

Discontinuous System Figure: 18-08 Title: The two new DNA strands have different features Caption: The leading strand is synthesized continuously while the lagging strand is synthesized discontinuously.

Figure: 18-09 Title: Helicases use ATP hydrolysis to unwind DNA Caption: A hexameric helicase moves along one strand of DNA. It probably changes conformation when it binds to the duplex, uses ATP hydrolysis to separate the strands, and then returns to the conformation it has when bound only to a single strand.

Figure: 18-10 Title: A free 3' end is required for priming Caption: A DNA polymerase requires a 3'-OH end to initiate replication.

(1). (2). (3). Figure: 18-11 Title: There are many ways to generate 3' ends Caption: There are several methods for providing the free 3' - OH end that DNA polymerases require to initiate DNA synthesis.

Figure: 18-11.01 Title: There are many ways to generate 3' ends Caption: There are several methods for providing the free 3' - OH end that DNA polymerases require to initiate DNA synthesis.

Figure: 18-11.02 Title: There are many ways to generate 3' ends Caption: There are several methods for providing the free 3' - OH end that DNA polymerases require to initiate DNA synthesis.

Figure: 18-11.03 Title: There are many ways to generate 3' ends Caption: There are several methods for providing the free 3' - OH end that DNA polymerases require to initiate DNA synthesis.

Figure: 18-11.04 Title: There are many ways to generate 3' ends Caption: There are several methods for providing the free 3' - OH end that DNA polymerases require to initiate DNA synthesis.

Figure: 18-12 Title: Priming required helicase, SSB, and primase Caption: Initiation requires several enzymatic activities, including helicases, single-strand binding proteins, and synthesis of the primer.

중합효소의 베타소단위체는 활주꺽쇠의 역할을 담당 스스로 개시전 복합체 (핵심부위와 주형DNA)와 결합 못함 꺽쇠장전기의 도움이 필요. Figure: 18-13 Title: A dimer synthesizes lagging and leading strands Caption: DNA polymerase III holoenzyme assembles in stages, generating an enzyme complex that synthesizes the DNA of both new strands.

Figure: 18-15 Title: Separate enzyme units synthesize lagging and leading strands Caption: Leading and lagging strand polymerases move apart.

Figure: 18-16 Title: Leading and lagging catalytic units behave differently Caption: A replicase contains separate catalytic units for synthesizing the leading and lagging strands.

Figure: 18-17 Title: DNA replicases have a common set of functions Caption: The helicase creating the replication fork is connected to two DNA polymerase catalytic subunits, each of which is held onto DNA by a sliding clamp. The polymerase that synthesizes the leading strand moves continuously. The polymerase that synthesizes the lagging strand dissociates at the end of an Okazaki fragment and then reassociates with a primer in the single-stranded template loop to synthesize the next fragment.

Figure: 18-18 Title: Leading and lagging strands are coordinated Caption: Each catalytic core of Pol III synthesizes a daughter strand. DnaB is responsible for forward movement at the replication fork.

Figure: 18-19 Title: Core polymerase and the clamp recycle Caption: Core polymerase and the b clamp dissociate at completion of Okazaki fragment synthesis and reassociate at the beginning of the next Okazaki fragment.

Figure: 18-19.01 Title: Core polymerase and the clamp recycle Caption: Core polymerase and the b clamp dissociate at completion of Okazaki fragment synthesis and reassociate at the beginning of the next Okazaki fragment.

Figure: 18-19.03 Title: Core polymerase and the clamp recycle Caption: Core polymerase and the b clamp dissociate at completion of Okazaki fragment synthesis and reassociate at the beginning of the next Okazaki fragment.

Figure: 18-19.04 Title: Core polymerase and the clamp recycle Caption: Core polymerase and the b clamp dissociate at completion of Okazaki fragment synthesis and reassociate at the beginning of the next Okazaki fragment.

Figure: 18-19.02 Title: Core polymerase and the clamp recycle Caption: Core polymerase and the b clamp dissociate at completion of Okazaki fragment synthesis and reassociate at the beginning of the next Okazaki fragment.

Figure: 18-20 Title: Each Okazaki fragment is synthesized individually Caption: Synthesis of Okazaki fragments requires priming, extension, removal of RNA, gap filling, and nick ligation.

Figure: 18-21 Title: DNA ligase uses an AMP intermediate Caption: DNA ligase seals nicks between adjacent nucleotides by employing an enzyme-AMP intermediate.

Figure: 18-22 Title: DNA polymerases undertake replication or repair Caption: Eukaryotic cells have many DNA polymerases. The replicative enzymes operate with high fidelity. Except for the b enzyme, the repair enzymes all have low fidelity. Replicative enzymes have large structures, with separate subunits for different activities. Repair enzymes have much simpler structures.

Figure: 18-23 Title: The origin has two sets of repeats Caption: The minimal origin is defined by the distance between the outside members of the 13-mer and 9-mer repeats.

Figure: 18-24 Title: Strand separation initiates at the origin Caption: Prepriming involves formation of a complex by sequential association of proteins, leading to the separation of DNA strands.

Figure: 18-25 Title: DNA damage can halt replication Caption: Replication is halted by a damaged base or nick in DNA.

Figure: 18-26 Title: A stalled replication fork can restart Caption: The primosome is required to restart a stalled replication fork after the DNA has been repaired.