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Friedrich Miescher
Discovery of Nucleic Acid. Isolated the genetic material from white blood cell nuclei. He noted it had an acid nature and called it nuclein. -
Phoebus Levene
Discovery of DNA Components. Adenine, Guanine, Thymine, Cytosine, Deoxyribose, Phosphate.
Defined phosphate-sugar-base units called nucleotides.
4 nucleotides per molecule. -
Frederick Griffith
Studied the epidemiology and pathology of 2 strains of Streptococcus Pneumoniae.
Type S → Virulent
Type R → Non-virulent
Reported the first widely accepted demonstrations of bacterial transformation. -
Oswald Avery - Colin MacLeod - Maclyn McCartey
Determinate the cause of the transformation inGriffith’s experiment.
They took live R and heat-treated S and mixed it with one of two enzymes.
- Proteases which destroys protein.
- DNase which destroys DNA. -
James Watson - Francis Crick
Wrote a paper in which they described DNA as a double helix with sugars and phosphates at the center and the nucleobases facing the outside. -
Erwin Chargaff
Counting Nucleobases -
Alfred Harshey - Martha Chase
DNA, not protein, was the genetic material.
A protective protein coat was formed around the bacteriophage, but the internal DNA is what conferred its ability to produce progeny inside bacteria. -
Linus Pauling
Triple Helix -
Rosalind Franklind
Photo 51 -
James Watson - Francis Crick
Correct Double Helix -
James Watson - Francis Crick - Maurice Wilkins
Receive the Nobel Prize in Physiology or Medicine.
For their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material.
