biology

disease causing strain of a bacteria

was trying to discover cure for pneumonia, used the smooth and rough colonies/heat killed bacteria and discovered that transformation(transfer of genetic material from one cell to another or from one organism to another) happens

wanted to find transforming agent, created extract and killed rna, dna, protein and discovered that transformation didn't occur when dna was not present; therefore dna is the transforming agent

tested whether viruses transfer dna or protein, marked protein with radioactive sulfur(35S) and dna with radioactive phosphorus (32P), allowed the virus to infect bacteria then separated with centrifuge, concluded: dna is the hereditary molecule in viruses

virus that infects bacteria