Paradox of biodiversity consists of all types of plants and animals in which I tell you about difference interesting facts about living forms that exist in the world. Also that knowledge is useful for you .

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Sunday, March 24, 2019

DNA

                                                      DNA 

From the work of biochemist P.A levene in 1920 it become clear that the DNA is made up of four types of molecules . The molecules are called nucleotides each nucleotide is formed of three different 
Molecules. A five Carbon sugar ,a phosphate group and a nitrogenous base . But levene had mistakenly concluded that the four types of nucleotides are present in equal amounts in all DNA and they grouped in repeating units of four nucleotides which called tetra nucleotides.

                                                                                                  
But the work of Erwin chargoff and his colleagues (1950) disapproved levene’s  tetra nucleotides 
Theory .
 Their work also made it possible for Watson and crick (1953) to give a double helix model of DNA 
Double helix model in British journal nature.

Franklin and Wilkins relvealed about DNA 

DNA has helical structure like bannister of a spiral staircase 
It has a uniform diameter of 2nm 
The distance between successive nucleotides is 0.34nm 
The distance b/w turns of helix is 3.4nm. 

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