experiments

Griffith

studied two strands of pnemococcus and discovered that bacteria can take up and use foreign biomolecules from the environment; demonstrated that genetic material could be transferred between organisms

Avery

built on Griffith’s work by identifying DNA as the transforming principle; genetic info in contained in DNA and bacterial transformation is caused by DNA

Hershey-Chase

confirmed that DNA, not protein, is the genetic material in organisms; only DNA from the virus entered bacterial cells

Rosalind Franklin

through x-ray crystallography, discovered that DNA is helical and has a 2nm diameter, 3.4nm long turns, 10 nucleotides in each turn, and phosphates on the outside

Watson and Crick

discovered that the sugar-phosphate backbone is on the outside, nucleotide bases are on the inside, complimentary base pairing is present, and DNA is double stranded and antiparallel

Meselson-Stahl

demonstrated that DNA replicates semiconservatively, with each new DNA molecule containing contains one old strand and one new strand

Beadle and Tatum

discovered that the mutation of one gene in a DNA sequence caused a change in one specific enzyme; concluded that one gene is responsible for each enzyme or protein

Srb and Horowitz

proved that specific genes control specific steps in biochemical pathways

Nirenberg-Matthai

discovered that codons specify amino acids