As dna side

Scientists of DNA

By marygrace.hardin2019

  • Frederick Miescher

    Frederick Miescher
    The Swiss physician is known for being the man who discovered DNA, believing that proteins were the molecules of inheritance. His findings were based on the results found when isolating a high phosphorous-containing substance from white blood cell nuclei. Bandages from nearby clinics and later salmon sperm were used to extract the so-called nuclein. He called this substance 'nuclein' because it had originated from the nucleus though he did not know its true nature at the time.

  • Erwin Chargaff

    Erwin Chargaff
    Chargaff partly solved the base-pairing mystery and said that even though different organisms have varying amounts of DNA, the amount of thymine is always equal to amount of adenine (same goes for cytosine and guanine). The biochemist furthered this and stated that human DNA contains about 30 percent each of adenine and thymine, and around 20 percent each of cytosine and guanine. This finding, known as Chargaff's Rule, allowed Watson to solve the pairing rules in the coming years.

  • Alfred Hershey & Martha Chase

    Alfred Hershey & Martha Chase
    A series of experiments involving T2 bacteriophage, the virus that infects E. coli bacterium and contained DNA and protein, were published by Hershey and Chase. This finally excluded proteins as being hereditary material. Radioisotopes were used and found that protein formed a protective coat around the bacteriophage, referring to phage replication; yet they did not find that DNA was the hereditary material. The intertwining question of DNA's structure and function was found soon after in 1953.

  • Francis Watson and James Crick

    Francis Watson and James Crick
    Not only did Watson and Crick provide a three-dimensional model of DNA, but they revealed the way in which DNA replicated. They had the idea that base pairing within the DNA strand and replication were connected, using stick-and-ball models. These ideas were based of the actual structure of a DNA molecule and later come up with the notion that replication occurs in a "semiconservative" manner. They referred to the complementary nature of DNA which became the semiconservative replication model.

  • Rosalind Franklin

    Rosalind Franklin
    Franklin used experimental methods and is mostly known for her x-ray diffraction image of the structure of DNA. The image which had been crystallized under moist conditions, showing a fuzzy X in the middle, was named 'Photo 51'. This photograph is what finally revealed the helical structure of DNA to Watson and Crick in 1953. She added to the discoveries previously made by Watson and Crick on the structure of DNA itself and was mentioned in Watson's book later on in 1968.

  • Matthew Meselson & Franklin Stahl

    Matthew Meselson & Franklin Stahl
    Both said that it would be possible to test each of the predictions about DNA, if there was a way to distinguish new versus old DNA. During Meselson and Stahl's Elegant Experiment, two isotopes of nitrogen were taken to see if the N atoms would be in the DNA of one or both of the daughter cells, and later grew a culture of E. coli bacteria. Both showed that DNA separated into two distinct bands, consistent with the semiconservative model of replication, stemming from Watson and Crick.

  • Bibliography 2

    O'Connor, Clare. "Isolating Hereditary Material: Frederick Griffith, Oswald Avery, Alfred Hershey, and Martha Chase." Nature.com. Macmillan Publishers, n.d. Web. 17 Jan. 2017. "Concept 15 DNA and Proteins Are Key Molecules of the Cell Nucleus." Friedrich Miescher :: DNA from the Beginning. © 2002 - 2011, DNA Learning Center, Cold Spring Harbor Laboratory, n.d. Web. 21 Jan. 2017. Digital image. N.p., n.d. Web. 17 Jan. 2017. https://lebbeuswoods.files.wordpress.com/2010/08/franklin-dna-1.jpg.

  • Bibliography 3

    Digital image. N.p., n.d. Web. 17 Jan. 2017. http://scarc.library.oregonstate.edu/coll/nonspcoll/catalogue/picture-dnamodel-600w.jpg. Digital image. N.p., n.d. Web. 17 Jan. 2017. https://dr282zn36sxxg.cloudfront.net/datastreams/f-d%3A0867f50f925ace9b82d0435730062864bc8858c44ce1b174592d1a40%2BIMAGE%2BIMAGE.1. Digital image. N.p., n.d. Web. 21 Jan. 2017. http://www2.sluh.org/bioweb/bi100/tutorials/dnastructure/whitecell.jpg.

  • Bibliography 4

    Digital image. N.p., n.d. Web. 17 Jan. 2017. http://www.bcsc.k12.in.us/cms/lib/IN01000842/Centricity/Domain/658/11-04.gif. Digital image. N.p., n.d. Web. 17 Jan. 2017. https://upload.wikimedia.org/wikipedia/commons/thumb/f/fb/Meselson-stahl_experiment_diagram_en.svg/491px-Meselson-stahl_experiment_diagram_en.svg.png. Digital image. N.p., n.d. Web. 21 Jan. 2017. http://molvisual.chem.ucsb.edu/Img/142A/As_DNA_side.png.

  • Bibliography 1

    "The Discovery of the Molecular Structure of DNA - The Double Helix". Nobelprize.org. Nobel Media AB 2014. Web. 17 Jan 2017. Arnold, Paul. "The History of DNA Discovery & The Scientists Who Discovered It." Bright Hub. N.p., 11 Sept. 2009. Web. 17 Jan. 2017. Pray, Leslie A. "Semi-Conservative DNA Replication: Meselson and Stahl." Nature.com. Macmillan Publishers, n.d. Web. 17 Jan. 2017.