Final answer:
Hershey and Chase's experiment in 1952 used T2 bacteriophage labeled with radioactive isotopes to demonstrate that DNA, not protein, is the hereditary material by showing that radioactivity from labeled DNA was found inside E. coli cells after infection.
Step-by-step explanation:
Martha Chase and Alfred Hershey conducted a landmark experiment in 1952 to determine whether genes were made of protein or DNA. They used T2 bacteriophage, which consists of a protein coat encasing DNA, to infect E. coli cells. Hershey and Chase labeled the DNA of one batch of T2 bacteriophage with radioactive phosphorus (32P), which is found in DNA but not protein. They labeled the protein of another batch with radioactive sulfur (35S), as sulfur is found in proteins but not in DNA.
Their experiment involved allowing the labeled T2 bacteriophages to infect E. coli cells and then using a blender to separate the phage's protein coats from the infected bacteria. After centrifugation, they could determine where the radioactivity from each type of label ended up. If the pellet at the bottom of the centrifuge tube, which contained the bacterial cells, was radioactive, this indicated that the labeled material had entered the cells. The results showed that radioactivity from 32P, but not from 35S, was found inside the cells, implicating DNA as the material responsible for transferring genetic information, and thus the hereditary material.