<P> The Hershey--Chase experiments were a series of experiments conducted in 1952 by Alfred Hershey and Martha Chase that helped to confirm that DNA is genetic material . While DNA had been known to biologists since 1869, many scientists still assumed at the time that proteins carried the information for inheritance because DNA appeared simpler than proteins . In their experiments, Hershey and Chase showed that when bacteriophages, which are composed of DNA and protein, infect bacteria, their DNA enters the host bacterial cell, but most of their protein does not . Although the results were not conclusive, and Hershey and Chase were cautious in their interpretation, previous, contemporaneous, and subsequent discoveries all served to prove that DNA is the hereditary material . </P> <P> Hershey shared the 1969 Nobel Prize in Physiology or Medicine with Max Delbrück and Salvador Luria for their "discoveries concerning the genetic structure of viruses ." </P>

Who used viruses to determine that dna was the molecule of heredity