The road to DNA, its importance and structure

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

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

Hershey and Chase: 1952

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

Waston and crick: 1953 Double helix model

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

Chromosome structure: later

DNA structure Antiparallel: opposite directions

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.