1. DNA Replication
DNA is copied – this is called replication
Without DNA replication, a new cell would only have half of it’s information.
All organisms undergo DNA replication

5. The original DNA now has a complimentary strand.

6. The result is two DNA molecules which is identical to the original.

7. DNA Replication Meselson and Stahl (1957)
Process called semi-conservative replication

8. Experiment

9. DNA of heavy, light, and intermediate densities can be separated by centrifugation.

10. Experimental Results

11. Experimental Results

12. Semiconservative: 1 new strand (daughter)+ 1 old (parent)

14. RNA primase

15. Direction of replication

16. Direction of replication

17. Direction of replication

18. Direction of replication

19. Direction of replication

20. Replication Fork

21. Replication Fork

24. שים מעבר לתוכנית

29. לשם פעולתו של אנזים דנ"א פולימרז נחוצה נוכחותם של ארבעה גורמים:
       i. תבנית דנ"א.
      ii. רצף חד-גדילי הרנ"א משלים לאיזור התחלה של ההכפלה לתבנית דנ"א . רצף זה קרוי פרימר.
     iii.  יוני Mg+2 (קופקטור של אנזים דנ"א פולימרז)
     iv. ארבעה סוגי חומרי מוצא:dTTP, dCTP , dGTP , dATP .

32. DNA template with synthesis of a new strand in the 5' to 3' direction.
The replication fork
DNA template with synthesis of a new strand in the 5' to 3' direction.

33. The lagging strand fragments are called Okazaki fragments after their discoverer, Reiji Okazaki.

38. The RNA primers are removed

39. the fragments Okazaki are joined by DNA ligase.

40.    DNA template with synthesis of a new strand in the 5' to 3' direction.

41. RNA primers are used to initiate a new strand

42. The two antiparallel strands are replicated simultaneously in both directions.

43. The lagging strand fragments are called Okazaki fragments after their discoverer, Reiji Okazaki.

44. DNA structure predicts that base sequence determines replication of DNA

45. All DNA polymerases synthesize from 5' 3'

46. Enzymes/proteins in DNA replication in E. coli
Helicase Unwinds DNA
Primase Adds RNA primer
single stranded binding protein Stabilizes
DNA polymerase III Synthesizes DNA
DNA polymerase I Erases primer,fills gaps
DNA polymerase II uncertain
DNA ligase Joins ends of DNA fragments

48. The two antiparallel strands are replicated simultaneously in both directions.

49. Replication Fork

50. Replication Fork -end