The Hershey-Chase experiment is a classic experiment in molecular biology that was conducted by Alfred Hershey and Martha Chase in 1952. It was designed to determine the role of DNA and protein in the replication of the bacteriophage T2.
The Hershey-Chase experiment involved infecting bacterial cells with bacteriophage T2, which is a virus that infects bacteria. The bacteriophage T2 consists of a protein coat that surrounds its genetic material, which is either DNA or RNA.
The infected bacterial cells were then incubated for a period of time to allow the bacteriophage T2 to replicate. The replication process involves the bacteriophage T2 injecting its genetic material into the bacterial cell, where it uses the cell’s machinery to replicate.
After the incubation period, the bacterial cells were separated into two fractions: the cell debris and the infected cell lysate. The cell debris contained the protein coat of the bacteriophage T2, while the infected cell lysate contained the genetic material of the bacteriophage T2.
The cell debris and infected cell lysate were then labeled with different isotopes of sulfur and phosphorus. The cell debris was labeled with sulfur-35, while the infected cell lysate was labeled with phosphorus-32. This allowed the researchers to track the movement of the protein coat and the genetic material during the replication process.
The results of the Hershey-Chase experiment showed that the protein coat of the bacteriophage T2 remained in the cell debris, while the genetic material of the bacteriophage T2 was incorporated into the infected bacterial cell. This demonstrated that DNA, not protein, is the genetic material of the bacteriophage T2.
The Hershey-Chase experiment was a significant milestone in the field of molecular biology, as it provided strong evidence for the role of DNA in the replication of viruses. It was also a key step in the development of the modern understanding of the structure and function of DNA.