Bacteriophag phosphorus labeled sulFur labeled DNA core protein capsule Cc s I nection 2. Blending 3. Centrifugation No sulfur detected in cells Phosphorus detected in cells Sulfur detected in No phosphorus supematant detected in supematant The Hershey-Chase Experiment
Transformation experiments Live avirulent non-encapsulated strain (rough strain) of Streptococcus pneumoniae Health Health No growth 转∞ 化 Heat-killed encapsulated irulent strain(smooth strain) 试 of Streptococcus pneumoniae Health Health No growth 验 Encapsulated virulent strain(smooth strain)of Growth of encapsu Streptococcus pneumoniae Health Dead strain →+ Live avirulent strain Growth of Heat-killed lated strain capsulated Health Dead
转 化 试 验 Transformation experiments
DNA labelled Put in blender to Labelled DNA inside cell 32P shake loose labelled Labelled protein remains outside protein coats Protein coat 噬菌体感染试验 Bacterial el Phage "ghosts"separate
噬菌体感染试验
DNA T4 bacteriophage are infecting E coli
T4 bacteriophage are infectng E.coli
THE STRUCTURE OF DNA one helical turn =34nm Sugar- phosphate Base Hydrogen bonds