Today’s Outline

1. Today’s Outline • DNA and DNA Replication Review • Leading Strand vs. Lagging Strand • DNA Pol I vs. DNA Pol III • Telomeres • Molecular Sculpting • DNA Replication • PCR • What’s Due? • StudyNotes 7 is due on Thursday Mar 21 • HW # 5 and is due on Tuesday Mar 26. • StudyNotes 8a is due on Tuesday Mar 26.

2. hydrogen bonds

3. Strand

4. 5’ carbon 5’ carbon 3’ carbon 3’ carbon

6. A DNA Double Helix has a regular, repeated structure

10. DNA Polymerase III Adds dNTPs to the newly synthesized strand on the leading strand. Adds to the 3’ end of a ribose.

11. DNA Polymerase I DNA Primase creates primers (red) that are RNA molecules. DNA Pol I replaces the RNA nucleotides with DNA nucleotides.

13. 5 Ends of parental DNA strands Leading strand Lagging strand 3 5 3 Last fragment Previous fragment Lagging strand RNA primer 5 3 Parental strand Removal of primers and replacement with DNA where a 3 end is available DNA Pol1 Can only add nucleotides to the 3’ end of existing DNA. 5 3 Telomeres protect an organism’s genes from being eroded during successive rounds of DNA replication. In humans the sequence TTAGGG is repeated between 100 and 1000 times. Second round of replication 5 New leading strand 3 5 New lagging strand 3 Further rounds of replication Shorter and shorter daughter molecules

14. Molecular Sculpting Two Models: • DNA Replication – must include: • Helicase, topoisomerase, single strand binding proteins, DNA primase, the sliding clamp, DNA pol I, DNA pol III and ligase. • Okazaki fragments, RNA primers, leading strand, lagging strand, nucleotides and free dNTPs. • Polymerase Chain Reaction – must include: • Three panels: denaturing, annealing and extending. • DNA, forward and reverse DNA primers, taq polymerase, dNTPs.