GRIFFITH’S EXPERIMENT SWBAT identify DNA as the transforming agent

WHAT DO YOU KNOW ABOUT DNA?

BEFORE GRIFFITH Scientists knew DNA was made of phosphate- sugar-base  Did not know the structure or role  DNA had been identified but not understood In 1927 Kolstov proposed there was the hereditary molecule  Did not know which molecule was hereditary (DNA)

FREDERICK GRIFFITH ( ) Worked in a very basic lab with cheap equipment  “Could do more with a kerosene tin and primus stove than most men could do with a palace” Was an expert on Pneumococcus  Collected samples from patients all over England

PNEUMOCOCCUS: BACTERIA Has two forms: Rough (R) and Smooth (S)  Rough is nonvirulent doesn’t cause illness  Smooth is Virulent; Makes people sick Can be killed by heat

GRIFFITH’S EXPERIMENTS Injected mice with live R Pneumococcus: Mice lived Injected mice with live S Pneumococcus: Mice died Injected mice with heat-killed S Pneumococcus: Mice lived Injected mice with live R and heat-killed S Pneumococcus: Mice died

AFTER GRIFFITH’S EXPERIMENT Scientists first thought Griffith messed up Later these experiments were redone and were proven right