Griffith+and+Transformation

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 * __Griffith & Transformation__**
 * Main Question: **How do bacteria make people sick?**
 * Expreimental bacteria: **pneumonia**

Griffith -Wanted to figure out how bacteria made people sick, particuarlly how bacteria caused pneumonia a leathal type of lung disease.

-He isolated two slightly different strains of pneuomia bacteria from mice -both grew well...

pneumonia A-> smooth colonies on petridishes-> caused disease pneumonia B-> rough colonies on petridishes-> harmless

-Because the different bacteria strands were so physically different they were easy to tell apart


 * Procedure:

Mouse 1: injected with pnumonia A-> dies of disease Mouse 2: injected with pnumonia B-> did not get sick Mouse 3: injected with heat sterilizd pnumonia A-> same result as mouse 2

Conclusion: disease was not a chemical poison released from bacteria

Continuation of experiment: Mouse 4: injected with mixture of heat sdterilized pneumonia A and um-tampered pnumonia B-> died of pnumonia A

-Somehow the heat-killed had passed their disease-causing ability to the harless strain, thus killing the mice who were injected with both the dead pnumoia cells and the live harmless ones. Griffith called this process transfomation.

-Bacterial transformation is the process by which bacterial cells take up naked DNA molecules. If the foreign DNA has an origin of replication recognized by the host cell DNA polymerases, the bacteria will replicate the foreign DNA along with their own DNA.

Conclusion: somehow the disease-causing agent of pneumonia A transformed pneumonia B into pneumonia A. -> Factor might be a gene, because disease causing agent was passed to offspring of transformed pneumonia B.