biology time line

  • Discovery of nucleic acids ( Friedrich Miescher)

    Discovery of nucleic acids ( Friedrich Miescher)

    Took out the genetic material from the nucleus of white blood cells.
    He saw it was acidic and called it nuclein.
  • Dicovery od DNA components, Phoebus Levene, (1869)

    Dicovery od DNA components, Phoebus Levene, (1869)

    Found the parts of DNA: adenine, guanine, thymine, cytosine, deoxyribose sugar, and phosphate.
    Said that DNA is made of small units called nucleotides.
    Each nucleotide has three parts: a sugar, a phosphate, and a base.
  • Counting Nucleobases, Erwin Chargaff, Austrian bioch

    Counting Nucleobases, Erwin Chargaff, Austrian bioch

    Used paper tests and UV light to study how many nucleobases there were. He began to see something very strange.
  • Frederick Griffith, Brithis becteorologist, (1879-1941)

    Frederick Griffith, Brithis becteorologist, (1879-1941)

    Studied two types of the bacteria Streptococcus pneumoniae. In January 1928, he showed for the first time that bacteria can transformation.
  • Maurice Wilkins, New Zeland physicist

    Maurice Wilkins, New Zeland physicist

    Around 1951–1952, he studied DNA fibers using X-ray diffraction. He shared some results without Franklin knowing, and these results later helped Watson and Crick.
  • Rosalind Franklind, british biophysicist

    Rosalind Franklind, british biophysicist

    Between 1951 and 1953, she made very clear X-ray pictures of DNA, including the famous Photo 51. This photo was very important for showing that DNA has a double helix shape.
  • Hershey-chase experiment, Alfred Hersey

    Hershey-chase experiment, Alfred Hersey

    He was a scientist who studied viruses called bacteriophages. He helped make a famous experiment to see if DNA or proteins carry genetic information.
  • Triple Helix? Linus pauling, american biochemist

    Triple Helix? Linus pauling, american biochemist

    Linus Pauling and Robert Corey suggested that DNA has three strands twisted together, like a triple helix.
  • Hershe- Chase experiment, Martha Chase, American

    Hershe- Chase experiment, Martha Chase, American

    She was his assistant in the laboratory. She carried out the experiment using radioactive labels to follow the molecules. With her work, she showed clearly that DNA, not proteins, is the material that carries genetic information.