Dhismaha dhismeedka DNA iyo RNA

Haddii aan qiyaasi muuqaalka kore ee Britain ayaa DNA ah waxay u ekaan muquuninta qaloocin, taas oo la aasaasay by laba silsiladood polynucleotide kuwaas oo qaloocdo naftooda u dhexeeya iyo isku mar ku dhawaad mid ka mid ah faasas ay caadi.

Caadi ahaan, qaab-dhismeedka DNA waxaa loo arkaa nidaamka falanqaynta, kuna waari dhexdeeda sida ugu weyn - waa adag go'an (for caadiga ah xaalad) dezoksiribonukleozidmonofosfatov nidaamka interposition - dNMP, silsilad qaybaha polynucleotide.

In aan qaadheen mononucleotides gacanta ku biiray bonds phosphodiester, isu silsilado polynucleotide xiro waxay leeyihiin laba doorasho ee goobta kooxaha dhabta ah ee 5'-dhamaadka ee silsiladda waa koox phosphate ah, iyo koox OH waa wareegi jiray Z'-dhamaadka.

Haddii aan ka fiirsan Britain ayaa ka kooban laba qaybood, qaab-dhismeedka DNA waa sida in silsilad polynucleotide waxay noqon doontaa antiparallel midba midka kale. In circuit this kaydsan yihiin in qaab dhismeedka ku noqon doonaa sabab u xidhnahay hydrogen jira saldhigyadii A-T iyo GC, coplanar dhexeeya, dadab iyo in ay dhidibka ugu weyn ee u taagoo ee ka dari. Kuwa isdhexgalka hydrophobic, loo sameeyay saldhigyadii ee Britain noocan oo kale ah u dhexeeya, waxay bixiyaan xasiloonida ee guud ahaan galool labanlaab. Waayo, sida a Britain, qaab-dhismeedka DNA lagu gartaa complementarity ah silsilado polynucleotide, laakiin ay aqoonsi ma aha sida Halabuurka nucleotide ay ka duwan tahay.

Dheeraad ah, ka fiirsaneysa in ay tahay qaab-dhismeedka DNA ah, waa in la ogaadaa in Britain kasta oo gaar ah waa "ka buuxaan" in si adag u gaar ah, koromosoomyada gaar ah. koromosoomyada waxa ku jira noocyo kala duwan oo borotiinada oo u dhigma isku xigxiga oo si adag u qeexay qaab dhismeedka Britain DNA ah. borotiinada Kuwan waxaa lagu tilmaamay galay 2 qaybood: histones iyo borotiinada negistony. In dhismaha la DNA ee nuclear ee unugyada, borotiinada, kuwaas oo loo yaqaan chromatin.

Isagoo tilmaamaya qaab dhismeedka DNA, waxaa in la xuso in chromatin ka kooban yahay shan nooc oo histones, amarka total fiican kaas oo bixiya a histones bond aad u xoog badan leh DNA. adag ee histones oo u taagoo DNA qeexay qayb lifaqaya a 146 lammaane nucleotide, waxaa uga jawaabay, taasoo ay u sameeyaan nucleosomes.

Waxaa ka mid ah in qaab-dhismeedka borotiinada Britain DNA negistony matalaan kala duwan nooc oo borotiin sharciyeed, la xidhiidha gaar ah isku xigxigta, DNA. Sidoo kale, u taagoo DNA oo dhammeystira in qaab dhismeedka of falgalka bixinta biosynthesis.

Baro qaabka DNA iyo RNA gudahood falanqaynta nidaamka waa in ay ahaataa oo keliya in dhismaha, taas oo, markii la tixgelinayo qaabka DNA, waxaa lagama maarmaan ah in la tixgeliyo qaabka iyo RNA.

Its qaab dhismeedka hoose, iyo sidoo kale in ay dhacdo Britain DNA ah waa ribonukleozidmonofosfatov isugu xidhanyihiin geynta, sidaas, la tixgeliyo in, si ka duwan DNA, dhammaan noocyada RNA waxay leeyihiin oo kaliya mid ka mid silsilad ah polynucleotide galay. In qaabka ee Britain ayaa ku RNA iyo qaybood ay hal loo sameeyay, sidaas darteed loo yaqaan "hairpin" - spiralized siddo oo ku jira Midowga Afrika iyo saldhig GC iyo xasilin iyada oo lagala kulmo hydrogen.

Sida caadiga ah, Britain DNA celceliska ugu weyn ee ka kooban 150-labo nucleotide millionov, oo dhererkeeduna wuxuu afar sentimitir. Falanqaynta shaybaarka ee u taagoo sida waa mid aad u xanibayo waxbarasho ah, maxaa yeelay, markaan waa qoondaynta of nudaha, Britain, naylahana in ay aadka u burbursan oo ay noqoto wax badan ka yar oo size. Si aad u baabi'iyo this carqalad, in waxbarashada habka of PCR - qabashada reaction silsilad polymerase, taas waxaa eegista synthesizing qaybaha gaarka ah ee Britain ayaa DNA ah, iyo in loo qoondeeyo daraasaadka lagama maarmaanka u ah jajabkii ay.