DNA STRUCTURE

Introduction 

DNA are the storage site , that contains or codes our characters. And the DNA are the hereditary material that carries the informations

Main features of DNA 

* Deoxyribonucleic acid

* Also known as 'B' DNA 

* A type of nucleic acid 

* polymer of nucleotides

* Double helical structure ( Watson and Crick model )

* Double stranded structure

* 2 strands are antiparallel to each other

* Pentose sugar & phosphate are the back-bone

* Consist of 4 nitrogen bases adenine (A), cytosine (C), guanine (G), or thymine (T). 

* A form double bond with T

* G form tripple bond with C

* Adenine & guanine are purines

* Cytosine & thymine are pyrimidines

* One turn of DNA consists of 10 bonds of nitrogen bases ,360A°. So the distance between each bonds there were 3.6A°. Length of one turn is 34A° 

* 20A° as width

SHALLOW GROOVE & DEEP GROOVE

Deep groove is also known as minor groove

Shallow groove's another name is major groove

The strand backbones are closer together on one side of the helix than on the other. The major groove occurs where the backbones are far apart, the minor groove occurs where they are close together. The grooves twist around the molecule on opposite sides.

We can classify DNA on the basis of number of base pair's on each turn 

A dna - 11 base pairs - R

B dna - 10 base pairs - R

C dna - 9.33 base pairs - R

D dna - 8 base pairs - R

Z dna - 12 base pairs - L

{ R & L preparations cooling direction of DNA }