1. Chapter 16 The Molecular Basis of Inheritance

2. Scientists like Mendel and Morgan showed us how genes behave… Chapter 16 The Molecular Basis of Inheritance

3. Scientists like Mendel and Morgan showed us how genes behave but no one knew what genes were made of, until… Chapter 16 The Molecular Basis of Inheritance

4. Avery (1928) Chapter 16 The Molecular Basis of Inheritance

5. Avery (1928) Two strains of pneumonia bacteria: S (smooth) = deadly R (rough) = harmless. Chapter 16 The Molecular Basis of Inheritance

6. Avery (1928) S bacteria can transform R bacteria, making them S Chapter 16 The Molecular Basis of Inheritance

7. Avery (1928) S bacteria can transform R bacteria, making them S. Even heat-killed S bacteria can transform R bacteria. Chapter 16 The Molecular Basis of Inheritance

8. Hershey & Chase (1952) Chapter 16 The Molecular Basis of Inheritance

9. Hershey & Chase (1952) Grew phage viruses with radioactive sulfur or phosphorus Chapter 16 The Molecular Basis of Inheritance

10. Hershey & Chase (1952) Grew phage viruses with radioactive sulfur or phosphorus. Allowed viruses to infect cells. Chapter 16 The Molecular Basis of Inheritance

11. Hershey & Chase (1952) Separated infected cells from empty virus husks Chapter 16 The Molecular Basis of Inheritance

12. Hershey & Chase (1952) Separated infected cells from empty virus husks. Sulfur stayed with husks, phosphorus entered cells. Chapter 16 The Molecular Basis of Inheritance

13. Watson, Crick, & Franklin (1953) Chapter 16 The Molecular Basis of Inheritance

14. Watson, Crick, & Franklin (1953) Worked out the double helix structure. Chapter 16 The Molecular Basis of Inheritance

15. Meselson-Stahl (1950’s) Chapter 16 The Molecular Basis of Inheritance

16. Meselson-Stahl (1950’s) Cultured DNA with heavy nitrogen, then centrifuged it to find its density. Chapter 16 The Molecular Basis of Inheritance

17. Meselson-Stahl (1950’s) conservative Chapter 16 The Molecular Basis of Inheritance

18. Meselson-Stahl (1950’s) conservative Chapter 16 The Molecular Basis of Inheritance

19. Meselson-Stahl (1950’s) conservative Chapter 16 The Molecular Basis of Inheritance

20. Meselson-Stahl (1950’s) semi-conservative Chapter 16 The Molecular Basis of Inheritance

21. Meselson-Stahl (1950’s) semi-conservative Chapter 16 The Molecular Basis of Inheritance

22. Meselson-Stahl (1950’s) semi-conservative Chapter 16 The Molecular Basis of Inheritance

23. Meselson-Stahl (1950’s) dispersive Chapter 16 The Molecular Basis of Inheritance

24. Meselson-Stahl (1950’s) dispersive Chapter 16 The Molecular Basis of Inheritance

25. Meselson-Stahl (1950’s) dispersive Chapter 16 The Molecular Basis of Inheritance

26. Meselson-Stahl (1950’s) conservative Chapter 16 The Molecular Basis of Inheritance

27. Meselson-Stahl (1950’s) conservative Chapter 16 The Molecular Basis of Inheritance

28. Meselson-Stahl (1950’s) conservative Chapter 16 The Molecular Basis of Inheritance

29. Meselson-Stahl (1950’s) conservative Chapter 16 The Molecular Basis of Inheritance

30. Meselson-Stahl (1950’s) conservative Chapter 16 The Molecular Basis of Inheritance

31. Meselson-Stahl (1950’s) conservative Chapter 16 The Molecular Basis of Inheritance

32. Meselson-Stahl (1950’s) semi-conservative Chapter 16 The Molecular Basis of Inheritance

33. Meselson-Stahl (1950’s) semi-conservative Chapter 16 The Molecular Basis of Inheritance

34. Meselson-Stahl (1950’s) semi-conservative Chapter 16 The Molecular Basis of Inheritance

35. Meselson-Stahl (1950’s) semi-conservative Chapter 16 The Molecular Basis of Inheritance

36. Meselson-Stahl (1950’s) semi-conservative Chapter 16 The Molecular Basis of Inheritance

37. Meselson-Stahl (1950’s) dispersive Chapter 16 The Molecular Basis of Inheritance

38. Meselson-Stahl (1950’s) dispersive Chapter 16 The Molecular Basis of Inheritance

39. Meselson-Stahl (1950’s) dispersive Chapter 16 The Molecular Basis of Inheritance

40. Meselson-Stahl (1950’s) dispersive Chapter 16 The Molecular Basis of Inheritance

41. Meselson-Stahl (1950’s) dispersive Chapter 16 The Molecular Basis of Inheritance

42. Meselson-Stahl (1950’s) So what really happened? Chapter 16 The Molecular Basis of Inheritance

43. Meselson-Stahl (1950’s) So what really happened? Chapter 16 The Molecular Basis of Inheritance 1 st replication →

44. Meselson-Stahl (1950’s) So what really happened? Chapter 16 The Molecular Basis of Inheritance 1 st replication →

45. Meselson-Stahl (1950’s) So what really happened? Chapter 16 The Molecular Basis of Inheritance 1 st replication → 2 nd replication →

46. Meselson-Stahl (1950’s) So what really happened? Chapter 16 The Molecular Basis of Inheritance 1 st replication → 2 nd replication →

47. A large team of enzymes carries out DNA replication Chapter 16 The Molecular Basis of Inheritance

48. A large team of enzymes carries out DNA replication 1. Replication begins at origins of replication. Chapter 16 The Molecular Basis of Inheritance

49. A large team of enzymes carries out DNA replication 2. A primer (short strand of RNA) is attached to DNA. Chapter 16 The Molecular Basis of Inheritance

50. A large team of enzymes carries out DNA replication 3. Y-shaped replication forks form at opposite ends of a replication bubble. Chapter 16 The Molecular Basis of Inheritance

51. A large team of enzymes carries out DNA replication 4. DNA polymerases work in the 5’ → 3’ direction. Chapter 16 The Molecular Basis of Inheritance

52. A large team of enzymes carries out DNA replication 5. Synthesis produces a continuous leading strand and Okazaki fragments on the lagging strand. Chapter 16 The Molecular Basis of Inheritance

53. A large team of enzymes carries out DNA replication 6. Okazaki fragments are joined together by DNA ligase. Chapter 16 The Molecular Basis of Inheritance

54. A large team of enzymes carries out DNA replication 7. DNA polymerase proofreads new DNA and corrects errors in pairing. Chapter 16 The Molecular Basis of Inheritance

55. A large team of enzymes carries out DNA replication 8. In excision repair, enzymes can cut out and replace damaged DNA. Chapter 16 The Molecular Basis of Inheritance

56. A large team of enzymes carries out DNA replication 9. Telomeres (ends of DNA) get shorter with each replication. Chapter 16 The Molecular Basis of Inheritance

57. A large team of enzymes carries out DNA replication 10. Telomerase can extend the ends.. Chapter 16 The Molecular Basis of Inheritance