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Period: to
DNA
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Fredrick Griffith
Fredrick Grithith conducted the first major experiment that led to the discovery of DNA.He studied two strains of bactiria that cause pnemonia.He found one had a sugar coat and the other did not. He conducted a expirement on mice and injected the smooth strand into one mice and injected the rough strand in the other mice. The mice with the smooth lived and the rough died from infection. -
P.A. Levene
P.A Levene determined the basic structure of nucleotides that make up DNA. Nucleotides are the subunits of nucleic acid and contian a 5 carbon sugar, a phosphate group and a nitrogenous base.They are in DNA and RNA. -
Oswald Avery
Oswald Avery and his colleauges found the molecule that transformed the R strand of bactiria to the S strand. He isolated macromolecules from the killed S cells, then exposed the live R cells to the macromolecules.The R cells that were exposed to the macromolecules they were transformed to S cells. He concluded that when the s cells were killed the dna was released and some of their bactiria accepted the dna into it so it changed. -
Erwin Chargaff
Erwin Chargaff analyzed the ammount of adenine,guanine,thymine, and cytosine. He found that the cytosine and the adenine are practically the same ammount and the guanine and the thymine were practically the same ammount. So he came up with the rule C=G and T=A. -
Hershey and Chase
Alfred Hershy and Martha Chase published results that proved that DNA is the transforming factor.There experiments had a type of viris that attacks bacteria. The viris that contained DNA and protien and since viruses cannot replaice themselves made their experiments ideal for confirming that DNA is genetic material.They used radioactive labeling in the virus to see where the DNA was. -
Rosalind Franklin
Rosalind Franklin discovered that there are two forms of DNA dry and wet.She pionered a microfocus X-ray camera and a technique to orient the DNA in beam. She also figured out a way to extract single DNA strands. Franklin got pictures that revealed keys to the structure of DNA.She also worked with Watson and Crick and they overall came up with the structure of DNA. -
Linus Pauling
Linus Pauling proposed a triple-helix structure for DNA.He had the phosphate groups facing in and the nitrogenous bases facing out.Three strands inertwined to make one helic DNA molecule. -
Maurice Wilkins
Maurice Wilkins worked with Watson, Crick ,and Franklin at King's College in London, England to discover the structure of DNA called the double helix. They worked with a technique called X-ray diffraction that aimed X-rays at DNA molecules. -
James Watson
James Watson worked alongside Francis Crick and with data from Chargaff and Franklin to meause the width of the Helix and the spacing out of bases.They created a model of the doubl helix that made sence with everyone else's work.Some important parts of their proposed molecule are two outside strands consist of alternating deoxyribose and phosphate,cytosine and guanine bases pair to each other by three hydrogen bonds, and thymine and adenine bases pair to each other by two hydrogen bonds. -
Francis Crick
Francis Crick worked alongside James Watson and with data from Chargaff and Franklin to meause the width of the Helix and the spacing out of bases.They created a model of the doubl helix that made sence with everyone else's work.Some important parts of their proposed molecule are two outside strands consist of alternating deoxyribose and phosphate,cytosine and guanine bases pair to each other by three hydrogen bonds, and thymine and adenine bases pair to each other by two hydrogen bonds.
