The hershey chase experiment on bacteriophages showed the genetic information is carried in <u>DNA.</u>
Explanation:
In 1952 Alfred Hershey and Martha Chase provided evidence that DNA is the genetic material. These scientists carried out an experimental work with the T2 virus, a bacteriophage that infects the Escherichia coli bacteria, which reproduces by attaching itself to the outer wall of the bacteria, injecting its DNA into it where it replicates and directs, the synthesis of phage proteins. Phage DNA is encapsulated within proteins and produces phages, which lyse or break the cell and releasing phage from the progeny. They used radioactive forms (isotopes) of phosphorus and sulfur. A radioactive isotope can be used as a marker to identify the location of a specific molecule, because any molecule that contains the isotope is radioactive and therefore easy to detect. The DNA contains phosphorus, but doesn't contain sulfur, therefore phosphorus-32 was used to mark the DNA, instead the protein has sulfur, but not phosphorus, so sulfur-35 was used. Hershey and Chase found that sulfur-35 is outside the cell while phosphorus-32 was inside, indicating that DNA was the physical support of the inheritance. This work allowed the scientists to conclude that it's the DNA and not the protein that enters the bacteria during phage reproduction and that only the DNA is transmitted to the phage of the progeny.
