Watson And crick Model of DNA or B-DNA

                                                                                      Watson and Crick presented a model to elucidate the molecular structure of DNA. Which is called DNA model. For this work, Watson and Crick were awarded the Nobel prize in 1962.

Key features of DNA model are as follows:-

1. Each section of DNA consists of two stands that wrap around each other form the double coil structure.
2. Each DNA has two chain of polynucleotides. Which is unbranched.
3. DNA has two polynucleotide chain Anti parallel. Hence, 3' of one series is near 5' of another series. Third Carbon independent of sugars at one end of polynucleotide series, Who says this 3' prime end. Fifth carbon Independent of sugar at second strand, Who says this 5' prime.
4. Both polynucleotides chain are linked By hydrogen Bond.

   

   
   
5. Nucleotides makes polynucleotides chain.(because Nucleotides are linked with Phosphodiester bond.)
6. Nucleotides as step-wise arrange. The two are arranged between the series.
7. Paring of Adenine to Thymine and pairing of Guanine to cytosine. Always Both are linked with Hydrogen bond.
8. In the DNA of each organism or caste. Nucleotides have certain sequence.
9. A=T/G≡C and A=T/G≡C ratio each organism established.
10. Both polynucleotides chain of DNA chain made of a helix is 34Å in length.
11. A total of 10 Nucleotides found in a complete helix, Distance between two Nucleotides is 3.4Å.
12. Diameter of every DNA coiled 20Å.
13. Both chain of DNA complement each other.If the sequence of bases one of its series is a A,G,A,T,G,C, then the order of bases in the second chain is T,C,T,A,C,G .
14. Two DNA sequences in each DNA chain(external grooves) which are called major grooves, respectively (major grooves) and minor grooves the major grooves is wide and deep.