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Discobery of Nucleic Acids
Friedrich Miescher discobery Nucleic Acids in 1869 -
Discovery of components of DNA
After discobery Nucleic Acids Phoebus Levene discober all of components of DNA, like phosphate, sugar and base all of that he named nucleotides. But he didn't get the structure he throught that was a tetranucleotides. -
First transformation
He basically demonstrate the bacterial transformation with a experiment with a mices and 2 types of bacteria streptococus, that had a transformation with an one of bactera to change the result of the experiment. -
Mechanism of transformation
Then Avery, McLeod and McCatry discoverd how woked that transformation. And discovered how do that rough non-virulent strain mixt with heat-killed smooth strain don't kill the mice that was with DNasa to kill DNA and that demostrate that the responsable of this was DNA. -
DNA form
With that there was a lot of confusion because DNA have two forms, form A and form B. Then Watson and Crick they describe DNA like a double helix, and then Linus Pauling and Robert Corey proposed a triple helix but that was incorrect. -
counting nucleobases
Erwin Chargaff took many organisms and then start to counting the amount of four types of bases. He saw that the Adenine and Thymine obtain a similar results and that Cytosine and Guanine had a similar results too, so was like a balance. -
Correct double helix
And the model of DNA was build with a photograf of Rosalind.