1. Figure: 11-01
Title:
Semiconservative Replication
Caption:
Generalized model of semiconservative replication of DNA. New synthesis is shown in teal.

2. Figure: 11-02
Title:
Conservative, Semi-conservative, or Dispersive Replication?
Caption:
Results of one round of replication of DNA for each of the three possible modes by which replication could be accomplished.

3. Figure: 11-03
Title:
The Meselson-Stahl Experiment
Caption:
The Meselson-Stahl experiment.

4. Figure: 11-03b
Title:
The Meselson-Stahl Experiment
Caption:
The Meselson-Stahl experiment.

5. Figure: 11-04
Title:
Expected Results of the Meselson-Stahl Experiment
Caption:
The expected results of two generations of semiconservative replication in the Meselson-Stahl experiment.

6. Figure: 11-05
Title:
The Taylor-Woods-Hughes Experiment
Caption:
The Taylor-Woods-Hughes experiment, demonstrating the semiconservative mode of replication of DNA in root tips of Vicia faba. (a) An unlabeled chromosome proceeds through the cell cycle in the presence of 3H-thymidine. As it enters mitosis, both sister chromatids of the chromosome are labeled, as shown by autoradiography. After a second round of replication (b), this time in the absence of 3H-thymidine only one chromatid of each chromosome is expected to be surrounded by grains. Except where a reciprocal exchange has occurred between sister chromatids (c), the expectation was upheld.

7. Figure: 11-06b
Title:
Bidirectional Replication of the E. coli Chromosome
Caption:
Bidirectional replication of the E. coli chromosome. The thin black arrows identify the advancing replication forks. The micrograph is of a bacterial chromosome in the process of replication, comparable to the figure next to it.

8. Figure: 11-07
Title:
The Chemical Reaction Catalyzed by DNA Polymerase I
Caption:
The chemical reaction catalyzed by DNA polymerase I. During each step, a single nucleotide is added to the growing complement of the DNA template using a nucleoside triphosphate as the substrate. The release of inorganic pyrophosphate drives the reaction energetically.

9. Figure: 11-08
Title:
Demonstration of 5’-to-3’ Synthesis of DNA
Caption:
Demonstration of 5’-to-3’ synthesis of DNA.

10. Figure: 11-09
Title:
Helical Unwinding of DNA During Replication
Caption:
Helical unwinding of DNA during replication as accomplished by DnaA, DnaB, and DnaC proteins. Initial binding of many monomers of DnaA occurs at DNA sites that contain repeating sequences of nine nucleotides, called 9mers. Not illustrated are 13mers, which are also involved.

11. Figure: 11-10
Title:
The Initiation of DNA Synthesis
Caption:
The initiation of DNA synthesis. A complementary RNA primer is first synthesized, to which DNA is added. All synthesis is in the 5’-to-3’ direction. Eventually, the RNA primer is replaced with DNA under the direction of DNA polymerase I.

12. Figure: 11-11
Title:
Opposite Polarity of DNA Synthesis Along the Two Strands
Caption:
Opposite polarity of DNA synthesis along the two strands, necessary because the two strands of DNA run antiparallel to one another and DNA polymerase III synthesizes only in one direction (5’-to-3’). On the lagging strand, synthesis must be discontinuous, resulting in the production of Okazaki fragments. On the leading strand, synthesis is continuous. RNA primers are used to initiate synthesis on both strands.

13. Figure: 11-12
Title:
Concurrent DNA Synthesis
Caption:
Illustration of how concurrent DNA synthesis may be achieved on both the leading and lagging strands at a single replication fork. The lagging template strand is “looped” in order to invert the physical direction of synthesis, but not the biochemical direction. The enzyme functions as a dimer, with each core enzyme achieving synthesis on one or the other strand.

14. Figure: 11-13
Title:
Summary of DNA Synthesis at a Single Replication Fork
Caption:
Summary of DNA synthesis at a single replication fork. Various enzymes and proteins essential to the process are shown.

15. Figure: 11-14
Title:
Multiple Origins of Replication along a Eukaryotic Chromosome
Caption:
A demonstration of the multiple origins of replication along a eukaryotic chromosome. Each origin is apparent as a replication bubble along the axis of the chromosome. Arrows identify some of these. (H. J. Kreigstein and D. S. Hogness, Proc. Natl. Acad. Sci. (USA) 71: 136. Fig. 2, p. 137.)

16. Figure: 11-15
Title:
Eukaryotic-replicating Fork
Caption:
An electron micrograph of a eukaryotic-replicating fork demonstrating the presence of histone protein-containing nucleosomes on both branches. (Dr. Harold Weintraub, Howard Hughes Medical Institute, Fred Hutchinson Cancer Center. Essential Molecular Biology, 2nd ed. Freifelder & Malachinski, Jones & Bartlett, Fig. 7-24, p. 141.)

17. Figure: 11-16
Title:
Replication of the Ends of Linear Chromosomes
Caption:
The difficulty encountered during the replication of the ends of linear chromosomes: A gap (marked --b--) cannot be filled following synthesis on the lagging strand.

18. Figure: 11-17
Title:
Telomerase Directs Synthesis of the TTGGGG Sequences
Caption:
The predicted solution to the difficulty posed in Figure The enzyme telomerase directs synthesis of the TTGGGG sequences, which results in the formation of a hairpin structure. The gap can now be filled, and the hairpin structure is cleaved.

19. Figure: 11-18a
Title:
Genetic Recombination
Caption:
Model depicting how genetic recombination can occur as a result of the breakage and rejoining of heterologous DNA strands. Each stage is described in the text. The electron micrograph shows DNA in a chi-form structure similar to the diagram in (g); the DNA is an extended Holliday structure, derived from the ColE1 plasmid of E. coli.

20. Figure: 11-18d
Title:
Genetic Recombination
Caption:
Model depicting how genetic recombination can occur as a result of the breakage and rejoining of heterologous DNA strands. Each stage is described in the text. The electron micrograph shows DNA in a chi-form structure similar to the diagram in (g); the DNA is an extended Holliday structure, derived from the ColE1 plasmid of E. coli.

21. Figure: 11-18g
Title:
Genetic Recombination
Caption:
Model depicting how genetic recombination can occur as a result of the breakage and rejoining of heterologous DNA strands. Each stage is described in the text. The electron micrograph shows DNA in a chi-form structure similar to the diagram in (g); the DNA is an extended Holliday structure, derived from the ColE1 plasmid of E. coli. (David Dressler, Oxford University, England)

22. Figure: 11-18h
Title:
Genetic Recombination
Caption:
Model depicting how genetic recombination can occur as a result of the breakage and rejoining of heterologous DNA strands. Each stage is described in the text. The electron micrograph shows DNA in a chi-form structure similar to the diagram in (g); the DNA is an extended Holliday structure, derived from the ColE1 plasmid of E. coli.

23. Figure: 11-19
Title:
Gene Conversion
Caption:
A proposed mechanism that accounts for gene conversion. A base-pair mismatch occurs in one of the two homologs (bearing the mutant allele) during heteroduplex formation, which accompanies recombination in meiosis. During excision repair, one of the two mismatches is removed and the complement is synthesized. In one case (top), the mutant base pair is preserved. When it is subsequently included in a recombinant spore, the mutant genotype is maintained. In the other case (bottom), the mutant base pair is converted to the wild-type sequence. When included in a recombinant spore, the wild-type genotype is expressed, leading to a nonreciprocal exchange ratio.

24. Figure: 11-UN01
Title:
Insight and Solutions
Caption:
Question 1. Predict the theoretical results of conservative and dispersive models of DNA synthesis using the conditions of the Meselson-Stahl experiment. Follow the results through two generations of replication after the cells have been shifted to an 14N-containing medium, using the following sedimentation pattern:

25. Figure: 11-UN02
Title:
Problems and Discussion
Caption:
Question 30: Given the diagram at the top of the next column, assume that the phase G1 chromosome on the left underwent one round of replication in 3H-thymidine and the metaphase chromosome on the right had both chromatids labeled. Which of the replicative models (conservative, dispersive, semiconservative) could be eliminated by this observation?

26. Figure: 11-UN03
Title:
Problems and Discussion
Caption:
Question 31: Consider the figure of a dinucleotide below. (a) Is it DNA or RNA? (b) Is the arrow closest to the 5’ or the 3’ end? (c) Suppose that the molecule was cleaved with the enzyme spleen diesterase, which breaks the covalent bond connecting the phosphate to C-5’. After cleavage, to which nucleoside is the phosphate now attached, deoxyadenosine or deoxythymidine?

27. Figure: 11-UN04
Title:
Problems and Discussion
Caption:
Question 32: DNA is allowed to replicate in moderately radioactive 3H-thymidine for several minutes and is then switched to a highly radioactive medium for several more minutes. Synthesis is stopped and the DNA is subjected to autoradiography and electron microscopy. Interpret as much as you can regarding DNA replication from the drawing of the electron micrograph presented here.

28. Figure: 11-T01
Title:
Table 11-1
Caption:
Base Composition of the DNA Template and the Product of Replication in Kornberg’s Early Work

29. Figure: 11-T02
Title:
Table 11-2
Caption:
Properties of Bacterial DNA Polymerases I, II, and III

30. Figure: 11-T03
Title:
Table 11-3
Caption:
Subunits of the DNA Polymerase III Holoenzyme

31. Figure: 11-T04
Title:
Table 11-4
Caption:
Some of the Various E. coli Mutant Genes and Their Products or Role in Replication