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GRIFFITH’S EXPERIMENT SWBAT identify DNA as the transforming agent.

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Presentation on theme: "GRIFFITH’S EXPERIMENT SWBAT identify DNA as the transforming agent."— Presentation transcript:

1 GRIFFITH’S EXPERIMENT SWBAT identify DNA as the transforming agent

2 WHAT DO YOU KNOW ABOUT DNA?

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4 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)

5 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

6 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

7 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

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


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