1. The road to DNA, its importance and structure

2. Griffith, Avery, Macleod 1944
Transformation: DNA could transform cells whereas proteins could not

3. Chargaff: 1947
Equal % of C and G
Equal % of A and T

4. Hershey and Chase: 1952

5. Franklin’s X-ray crystallography: early 1950’s
Had to be able to crystalize molecule
Regular pattern= helix

6. Waston and crick: 1953
Double helix model

7. Messelson and Stahl: late 1950’s: Semi-conservative replication

8. Chromosome structure: later

9. DNA structure
Antiparallel: opposite directions

10. Complementary: base pairs
Always one purine (double ring) A or G
Always one pyrimidine (single ring) C or T
A/T only has two H bonds so it is easier to unzip.