2. Milestones of the Last Century Going to the moon Computer technology Communications technology     Solving the structure of DNA and unraveling the mysteries of heredity

4. R r R r R r R r R r R r R r

5. DNA Carries the Code of Life How is genetic information (DNA) copied every time a cell divides? How is genetic information stored in DNA?

6. DNA Carries the Code of Life In 1953, Watson and Crick discovered the structure of DNA DNA is composed of a double helix

7. The Structure of DNA S = sugar P = phosphate B = base (A, G, C, T) - S - P - S - P - S - P - S - P - S - P - S - B B B B B B B B B B B B

8. DNA Contains Four Bases: A = Adenine G = Guanine T = Thymine C = Cytosine

9. DNA Base Pairing Rules: A always pairs with T G always pairs with C

10. The Structure of DNA S = sugar P = phosphate B = base (A, G, C, T) - S - P - S - P - S - P - S - P - S - P - S - G C A T A T T A T A C G

11. A G G C T A T C C A A G T A G G A T T C T C C G A T A G G T T C A T C C T A A G A G G C T A T T C C G A T A C C A A G T A G G A T T C A G T A G G A T T C T C A T C C T A A G G G T T C A T C C T A A G DNA Replication

12. A G G C T A T C C A A G T A G G A T T C T C C G A T A G G T T C A T C C T A A G A G G C T A T T C C G A T A C C A A G T A G G A T T C A G T A G G A T T C T C A T C C T A A G G G T T C A T C C T A A G DNA Replication A G G C T A T C C A A G T A G G A T T C T C C G A T A G G T T C A T C C T A A G A G G C T A T C C A A G T A G G A T T C T C C G A T A G G T T C A T C C T A A G

13. How is genetic information copied every time a cell divides? The two strands separate and each strand is used as a template for the synthesis of a new strand.

14. How is genetic information stored in DNA? As a sequence of bases (AGGCATTCGCAATT…)

15. the players…... James Watson and Francis Crick -solved the DNA structure -awarded the Nobel prize

16. the players…... Linus Pauling -winner of two previous Nobel prizes -was “hot on the trail” to solving the DNA structure, but lacked critical data

17. the players…... Rosalind Franklin - X-ray crystallography expert who generated key data for solving the structure of DNA

18. the players…... Erwin Chargaff - figured out the ratio of A = T and G = C - didn’t realize that this meant DNA was double stranded

19. The “Gurdon” experiment: Does every cell in an organism contain all the genetic information to make a complete individual?

20. Unfertilized egg Ultraviolet radiation of egg to destroy nucleus Enucleated egg Host egg

21. Donor nucleus

22. Host eggDonor nucleus