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Erwin Chargaff
In the mid 1900's Erwin Chargaff study DNA. What he found most amusing about DNA were four nitrogen bases of DNA. They are called adenine (A), guanine (G), cytosine (C), and thymine (T). He found that the A and T had about the same concentration in almost every species. He found the same thing for the G and C concentrations. What he found was
the the structure of DNA. -
Fredrick Griffith
In the 1920's Fredrick Griffith was experimenting with two types of
bacterium, A rough bacterium and a smooth bacterium. He found that if he injected the rough bacterium to a mouse, the mouse would live. When he injected the mouse with the smooth bacterium, the mouse would die but if he heated up the smooth bacterium then injected the mouse with it, the mouse would not die. When he mixed heated up smooth and non heated up rough the mouse would die. -
Oswald Avery
DNA was believed to be contained in cell proteins. Avery
discovered that this was false and that DNA transmits heredity. After Avery had received emeritus status from Rockefeller institute in 1943 he continued to working to prove that elder people could make discoveries too. His process to figure this out was that be removed various organic compounds from bacteria, and combining and taking many things trying to see what happened. He ended up figuring out that DNA was the carrier of genes in cell -
Alfred Hershey and Martha Chase
In the 1950's Martha Chase and Alfred Hershey work with viruses an bacteria they found that viruses are not cells, instead they are DNA inside of a protein coat. A virus will get its genetic material into a cell to reproduce. The experiment they did was use radioactive elements to see what molecule viruses inserted into a cel (bacterium). What molecule they found was DNA, therefore proving DNA is genetic material. Proving DNA is genetic material inspired Watson and Crick to
learn more about DNA. -
Rosalind Franklin
Rosalind Franklin was the first scientist to discover the the
structure of DNA. Even thought she was the first to find the structure of DNA she did not get a lot of credit. When Watson and Crick won the Nobel Peace Prize using one of her x-rays and, she did not get credit for what she had discovered. She used x-rays to look at the shape of DNA. Her famous x-ray, Photo 51 was the first visual photograph of
DNA's structure. Photo 51 along with her other x-rays were done in
1952. Her findings serve -
Watson and Crick
By the work of Alfred Hershey and Martha Chase, James Watson and Francis Crick wanted to learn more about DNA. In 1953 Watson and Crick discovered the shape of DNA. They found they DNA is wound up into a helix shape. A spiral staircase is an example of a helix. Without the work of the scientist before them, they would never of found the shape
of DNA.
