1. Passing on Life’s Information DNA Replication

2. Nucleotides

3. T.H. Morgan Genes are located on chromosomes

4. Transformation (Griffith 1928)

5. Avery, McCarty, MacLeod (1944) Genetic Material Protein or DNA ???? "Studies on the chemical nature of the substance inducing transformation of pneumococcal types"

6. Hershey & Chase (1952)

7. Chargaff’s Rule Adenine – Thymine Guanine - Cytosine

8. Watson & Crick

10. Maurice Wilkins X-ray diffraction

11. Rosalind Franklin

12. Nucleotides

13. X-ray Data

14. DNA Structure

16. Complimentary Strands

17. Semiconservative Model (Meselson & Stahl)

18. Origin of Replication

19. Antiparallel

20. Enzymes DNA Polymerase Helicase Single-strand binding protein Topoisomerase RNA primase Ligase

21. RNA Primer Uses RNA primase to build RNA primer Eventually replaced with DNA by DNA Polymerase

22. DNA Replication

23. Leading and Lagging Strands Leading Strand Built in the 5’-3’ direction Built toward the replication fork Built continuously Uses one RNA Primer Lagging Strand Built in the 5’-3’ direction Built away from the replication fork Built discontinuously using Okazaki fragments Many RNA Primers

24. Overview

25. Proofreading DNA – 3.2 billion base pairs Mistake – 1/100,000 After corrections – 1/1,000,000

26. End-replication Problem Nucleotides can only be added to 3’ end Leaves gap on leading strand Each replication causes DNA molecule to get smaller

27. Telomeres

28. End of DNA strand made up of reoccurring DNA sequence Can be rebuilt with telomerase (only in germ-line cells)