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mechudita mechudita
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11 years ago
What did Hershey and Chase demonstrate regarding radioactive tracers?
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#1
11 years ago
Back in the day people were still learning about infections and how viruses were reproducing. Hershey & chase did an experiment forget the name but they did a radioactive labeling technique to do two different types of labeling. The one type was a coat labeling and the other was an internal labeling. After both types had their radioactive labels they allowed them to infect or reproduce. They then took the infected and found the radioactive labeling only in the offspring with the internal labeling. This told them that the transferring of reproducing material was not the protein material on the coat but was the reproducing material on the inside "DNA" Deoxyribo-Nucleic Acids
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#2
11 years ago
They demonstrated that DNA is the genetic material, and not protein.

Basically, they grew two batches of bacteriophage, one on radioactive sulfur, and one on radioactive phosphorus.  The sulfur labeled the protein of the virus, but not the DNA, and the phosphorus labeled the DNA, but not the protein.

They infected two sets of bacteria with each type of labeled phage, spun the mixtures in a blender to detach the viruses from the bacteria, put the mixtures into a centrifuge, and analyzed the layers.  In the radioactive sulfur test tube, the bacteria were not radioactive, but the viruses were, meaning that the viral proteins did not enter the cells.  In the radioactive phosphorous test tube, however, the viruses were not radioactive, but the bacteria were, meaning that the viruses had injected the radioactively labeled DNA into the bacteria.
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