DNA vs RNA: blueprint vs messenger of life

 THE DNA

acidic substance prensent in nucleas  was first identify by friedrich in 1869 he named it nuclien 

. altman did complete study .identify acidic nature called nucleic acid. 

. DNA is long polymer chain of deoxy ribonucleiotides 

.length of DNA Is defined number of nucleotide .

structure of polynucleotide chain 

nucleotide contain : pentose sugar + nitrogenous base + phosphate 

pentose sugar are two types : deoxyribose sugar  and ribose sugar  

 .nitrogenous base such as -[adenine , guanine, cytocin, uracil, thymine, ] 

 . in case of  DNA  A,G,T,C.

in case of RNA   A,G,C,U.

. thymine are also known as 5methyl uracil .

DOUBLE HELIX STRUCTURE OF DNA

. in 1953 james wattson and francis crick based on the X ray diffrence data produced by  rosalind franklin proposed double helix structure of DNA . through X ray crystallography  obtained a very fine picture of DNA .

. its was suggested that structure of DNA was sort helix 3A periodicity 

 erwin chargraff rule :

its only for double stranded DNA 

. purines and pyramidines are euwal amount present   

. pyramidines of DNA are thymine and cytosin 

. A+G/T+C =value constant 

. sugar deoxy ribose phosphate residuse occuar in equal 

.purines adenine is equimotor with pyramidines thymine 

. purines guanine is equimotor with pyramidines and cyticin (C=G)

. two strand of DNA are attached to other via hyrogen bond 

A=T double hydrogen bond show 

 G=C triple hydrogen bond show

  salient feature of double helix DNA

1. two chain:

dna is made up of two strands with sugar phosphate backbone and bases pointing inward 

2.antiparallel:

 the strands are run in opossite direction  one from 5to 3 and other are 3to5

3. base pairing:

A   pair  with T with 2 hydrogen bond   G pair with C  with 3 hydrogen bond keeping strand evenly placed .

4.helical shape:

the strands twist into right hand helix with 10 base pair per turn 

5. stability :

bare pair are stack on a top of each other adding to DNA stability along with hydrogen bond .

note# length of DNA in human is 2.2m

. length of DNA e coli is 1.36mm.

packaging of DNA

1. packaging in prokaryotes 

. uses of non histone protein 

. they do not have a well defined nucleas 

. DNa is acidic in nature they have -ve charge held with  and histone protein have +ve charge region called nucleoid  eg e -coli 

2. packaging  in eukaryotes 

 packed by basic histone protein 

.protein aquire depending upon abudence of amnino acid and histone are rich in amino acid  

histone protein are formes octamer.

 nucleosome :

nagatively charge DNA are wrapped around positively charge histone protein called nucleosome .

two types of nucleosome 

1.euchromatin 

 packaging of DNA is loosely packed 

. lightly strained 

.transcriptionolly active convert into RNA . 

2. hetrochromatin

packaging of DNA is tightly.

.dark strained .

.transcriptionolly inactive not convert into RNA .

properties of genetic material DNA vs RNA

. a molecule can act genetic material it must fullfil criteria.

1.its should be chemically and structurally stable .

2.its should be able to generate it replicable.

3. its should be provide to scope for slow in mutation 

4. its should be  able to express itself in the form of medelian character.

note# both can be genetic material but DNA is genetic material which can storage of genetic information DNA.

but transformation of genetic information is RNA.

RNA WORLD

 . first genetic material essential life for life process .metabolism ,translation,etc 

. act as catalyst .being  catalyst its more reactive hence unstable.

.DNA has envolved RNA chemical changes that makes it unstable 

. DNA being double stranded complementry stranded envolving process of repair.

basic diffrence between DNA and RNA

why DNA IS MORE STABLE?

beacuse DNA has thymine (5 methyl uracil) and sugar of deoxyribose are more stable than  ribose sugar .and RNA is more reactive than DNA . DNAis less reactive due to OH bond at 5 carbon. hence DNA is more stable than RNA .