Nucleic acid and it's classification

Nucleic acids are biopolymers, macromolecules, essential to all known forms of life. They are composed of nucleotides, which are the monomer components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main classes of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). If the sugar is ribose, the polymer is RNA; if the sugar is the ribose derivative deoxyribose, the polymer is DNA.
Nucleic acids are naturally occurring chemical compounds that serve as the primary information-carrying molecules in cells and make up the genetic material. Nucleic acids are found in abundance in all living things, where they create, encode, and then store information of every living cell of every life-form on Earth. In turn, they function to transmit and express that information inside and outside the cell nucleus to the interior operations of the cell and ultimately to the next generation of each living organism. The encoded information is contained and conveyed via the nucleic acid sequence, which provides the 'ladder-step' ordering of nucleotides within the molecules of RNA and DNA. They play an especially important role in directing protein synthesis.

Strings of nucleotides are bonded to form helical backbones—typically, one for RNA, two for DNA—and assembled into chains of base-pairs selected from the five primary, or canonical, nucleobases, which are: adenine, cytosine, guanine, thymine, and uracil. Thymine occurs only in DNA and uracil only in RNA. Using amino acids and the process known as protein synthesis,[2] the specific sequencing in DNA of these nucleobase-pairs enables storing and transmitting coded instructions as genes. In RNA, base-pair sequencing provides for manufacturing new proteins that determine the frames and parts and most chemical processes of all life forms.
This article covers the chemistry of nucleic acids, describing the structures and properties that allow them to serve as the transmitters of genetic information. For a discussion of the genetic code, see heredity, and for a discussion of the role played by nucleic acids in protein synthesis, see metabolism.

1. NUCLEIC ACIDS (DNA & RNA)
•Nucleicacidsarelargebiomoleculeswhichfunctionin
encoding,transmittingandexpressinggeneticinformation.
Nucleotidesarebuildingblocksofnucleicacidsasthe
proteinsaremadeofaminoacids.
StructureofNucleotides:
•Nucleotideshavethreecharacteristiccomponents:
1.Abase(nitrogen-containing)
2.Apentosesugar
3.Aphosphate

3. A nitrogenous base
•Thenitrogenousbasesinnucleotidesarederivativesoftwo
parentcompounds--pyrimidineandpurine.
•Purines:Adenine&Guanine(A&G)
•Pyrimidines:Cytosin,Thymine&Uracil(C,TandU)•Pyrimidines:Cytosin,Thymine&Uracil(C,TandU)
•BothDNAandRNAcontaintwomajorpurinebases,Adenine
(A)andguanine(G)
•PyrimidinesinDNAarecytosine(C)andthymine(T).
•PyrimidinesinRNAarecytosine(C)anduracil(U).

4. •Nucleic acids have two kinds of pentoses
•DNA contains 2’-deoxy-D-ribose,
•RNA contains D-ribose.

5. Four major deoxyribonucleotides(deoxyribonucleoside5’
monophosphates) --
•Deoxyadenylate(deoxyadenosine5’-monophosphate) Symbols : dAMP
•Deoxyguanylate(deoxyguanosine5’-monophosphate) Symbols : dGMP
•Deoxythymidylate(deoxythymidine5’-monophosphate) Symbols: dTMP
•Deoxycytidylate(deoxycytidine5’-monophosphate) Symbols : dCMP

6. •Four major ribonucleotides(ribonucleoside5’-
monophosphates) ---
•Adenylate(adenosine 5’-monophosphate) Symbols : AMP
•Guanylate(guanosine5’-monophosphate) Symbols : GMP
•Uridylate(uridine5’-monophosphate) Symbols : UMP
•Cytidylate(cytidine5’-monophosphate) Symbols : CMP

7. Phosphate “Bridges”
•ThesuccessivenucleotidesofbothDNAandRNAare
covalentlylinkedthroughphosphate-group“bridges
•The5’-phosphategroupofonenucleotideunitisjoinedtothe
3’-hydroxylgroupofthenextnucleotide,creatinga3’-hydroxylgroupofthenextnucleotide,creatinga
phosphodiesterlinkage.
•Thusthecovalentbackbonesofnucleicacidsconsistof
alternatingphosphateandpentoseresidues,andthe
nitrogenousbasesmayberegardedassidegroupsjoinedto
thebackboneatregularintervals.

9. •DNAconsistsoftwohelicalchainsofnucleotideswoundaround
thesameaxistoformdoublehelix.ThetwoDNAstrandsare
organizedinananti-parallelarrangementi.e.onestrandis
oriented5’-3’andotherisoriented3’-5’.
•Thehydrophilicbackbonesofalternatingdeoxyriboseand
phosphategroupsareontheoutsideofthedoublehelix,facing
thesurroundingwater.thesurroundingwater.
•Thepurineandpyrimidinebasesofbothstrandsarestacked
insidethedoublehelix,withtheirhydrophobicandnearly
planarringstructuresveryclosetogetherandperpendicularto
thelongaxis.

10. •Eachnucleotidebaseofonestrandispairedinthesame
planewithabaseoftheotherstrand.GwithCandAwithT,
arethosethatfitbestwithinthestructure.Thisiscalled
complementarybasepairing.Threehydrogenbondscanform
betweenGandC,butonlytwocanformbetweenAandT.betweenGandC,butonlytwocanformbetweenAandT.

14. RNA
•MostRNAmoleculesaresinglestrandedbutanRNAmolecule
maycontainregionswhichcanformcomplementarybase
pairingwheretheRNAstrandloopsbackonit.IfsoRNAwill
havesomedouble–strandedregions.RNAmoleculesareof
threetypes.threetypes.
•mRNA(messengerRNA)–carriesmessageintheformof
codonsfromDNA
•rRNA(ribosomalRNA)–createssitewhereproteinsynthesis
takesplace
•tRNA(transferRNA)-specifictRNAwithspecificanticodon
carriesaminoacid