1. DNA Replication and Recombination
Chapter 11 Lecture
Concepts of Genetics
Tenth Edition
DNA Replication and Recombination

2. 11.1 DNA Is Reproduced by Semiconservative Replication

3. Figure 11-1 Generalized model of semiconservative replication of DNA
Figure 11-1 Generalized model of semiconservative replication of DNA. New synthesis is shown in blue.
Figure 11.1

4. Figure 11-2 Results of one round of replication of DNA for each of the three possible modes by which replication could be accomplished.
Figure 11.2

5. 11.1 DNA Is Reproduced by Semiconservative Replication
The Meselson–Stahl Experiment

6. Figure 11-3 The Meselson–Stahl experiment.

7. Figure 11-4 The expected results of two generations of semiconservative replication in the Meselson–Stahl experiment.
Figure 11.4

8. 11.3 Many Complex Tasks Must Be Performed during DNA Replication
Unwinding the DNA Helix

9. Figure 11-9 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 containing repeating sequences of 9 nucleotides, called 9mers. Not illustrated are 13mers, which are also involved.
Figure 11.9

10. 11.3 Many Complex Tasks Must Be Performed during DNA Replication
Initiation of DNA Synthesis With an RNA Primer

11. Figure 11-10 The initiation of DNA synthesis
Figure 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.
Figure 11.10

12. 11.3 Many Complex Tasks Must Be Performed during DNA Replication
Continuous and Discontinuous DNA Synthesis of Antiparallel Strands

13. Figure 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 ( to ). 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.
Figure 11.11

14. 11.3 Many Complex Tasks Must Be Performed during DNA Replication
Integrated Proofreading and Error Correction

16. 11.7 The Ends of Linear Chromosomes are Problematic During Replication
Telomere Structure
Replication at the Telomere

18. Figure Diagram illustrating the difficulty encountered during the replication of the ends of linear chromosomes. A gap (- -b- -) is left following synthesis on the lagging strand.
Figure 11.16

19. Figure The predicted solution to the problem posed in Figure 11–16. The enzyme telomerase directs synthesis of the TTGGGG sequences, resulting in the formation of a hairpin structure. The gap can now be filled, and, following cleavage of the hairpin structure, the process averts the creation of a gap during replication of the ends of linear chromosomes.
Figure 11.17