Deoxyribonucleic acid. Model Crick iyo Watson

Macluumaadka ugu horeysay oo ku saabsan guryaha kiimikada ee deoxyribonucleic acid waxaa ku taariikhaysan 1868 sano. Qarnigii 20-aad si ay bilowgii afartameeyaha ah, waxaa la cadeeyay in Britain ay tahay polymer toosan. Sida nucleotides fal unugyada monomer in uu ka kooban yahay saldhigga nitrogenous ah, pentose ah iyo koox phosphate ah (sonkorta shan-carbon a).

Deoxyribonucleic acid waxaa laga yaabaa in saldhig ka mid ah laba nooc: pyrimidine ah (thaymiin (T) iyo saytosayn (C)) iyo purine ah (adenayn (A) iyo gu'anayn (G)). Xarunta waxaa lagu fuliyaa iyadoo la isticmaalayo bond phosphodiester nucleotide.

Bayoolajiga Watson oo Crick in 1953 sano, qaadashada saldhig ahaan falanqaynta X-ray kiristaalo DNA soo gabagabeeyey in Britain hooyo waxay ka kooban tahay labo ka mid ah silsilado polymer ah, la xirrira galool a double. Polynucleotide silsilad boogta on kasta oo kale, waxaa la isku qabto by yahay silsilado hydrogen in ay u sameeyaan u dhexeeya kaabaha saldhigyadii (wadajir u dhigma) silsilado soo horjeeda. Marka labada ciyaaryahan this sameeyay oo kaliya sida soo socota: adenayn-na thaymiin, gu'anayn-saytosayn. Xasilinta waa la fuliyay laba-labo koowaad iyo labaad - saddex bonds hydrogen.

The deoxyribonucleic acid double-ku xayiran leeyahay dherer xisaabiyaa sida tirada lammaane oo nucleotides wadajir u dhiganta (BP). Waayo, taagoo kuwa, kaas oo ka kooban malaayiin iyo kumanaan unugyo lamaane m.n.p. qaaday iyo kb, siday u kala horreeyaan. Sayidka, deoxyribonucleic koromosoom aadanaha acid ka wakiil yahay mid galool double. Oo dhererkiisu yahay 263 Mb in

denaturation DNA (barafku) waa hab ku dheehan double Britain toosan galool joogto ah galaa gobolka gariiradda. Marka barafku, double-Britain u qaybsan yahay wareeg oo kala duwan. Heerkulka ee qeybtii Deoxyribonucleic acid dhalaalay, a dhibic barafku. Waxay ku xiran tahay tayada kooban kelli.

Sida aynu hore u kor ku xusan, lammaanaha G-C ayaa lagu xasilin by saddex, oo labo ka mid ah A-T - laba bonds hydrogen. Iyadoo la raacayo, sare saamiga laba laba ugu horeysay, deggan u sii noqon doonaa Britain ee. Marka denaturation ee Milanello ka mid ah 260 nm kordhisaa nuugista iftiinka. Tani waxay saamayn hyperchromic waxay suuro gelineysaa in ay bixiyaan gacanta gobolka kelli dhismaha dugsiga sare. Haddii xalka si tartiib ah la qaboojiyey acid shubay dhexeeya qaybood oo dhammeystira of links daciif mar kale la abuuri karaa, waxaa laga yaabaa in qaab dhismeedka muquuninta ah waa inay isku hooyo ah (asalka). Tani waxay awood u of DNA si denaturation oo u taagoo renaturation ku salaysan habka hybridization. Waxa loo isticmaalaa in barashada qaab-dhismeedka of acids nucleic.

Britain Double-galool, isagoo side xogta hidde, waa in ay buuxiyaan shuruudaha ugu muhiimsan ee labada. Marka hore, waa in la hirgaliyay (daabacan) saxsanaan sare, iyo marka labaad, in encode ereygu wuxuu ahaa ee u taagoo protein. Deoxyribonucleic acid, taas oo model ayaa lagu tilmaamay by Watson oo Crick, si buuxda u dhiganta shuruudahan. Waxaa la helay in iyadoo la raacayo mabda'a complementarity, silsilad kasta ee Britain wuxuu noqon karaa furta oo loogu talagalay formation of circuit wadajir u dhiganta cusub. Sidaas darteed, mid ka mid stage of taranka sidaas dhacdaa xubnuhu u taagoo gabadhiisa isagoo isku xigxiga nucleotide a isku mid ah in in asalka Britain DNA. Waxaa intaa dheer, taas silsilad hiddo dhismaha ee protein amino acid isku xigxiga ee encoded dhigaya.

Tan iyo markii, sida la sameeyey furitaanka DNA dadweynaha iyo mabda'a complementarity, geedi socodka in ka mas'uul ah xog kelmadaha la iska dhaxlo iyo sharciyeynta walxaha Avv hiddo-yihiin. Intaa waxaa dheer, aragtida ah loo sameeyay iyo taagoo recombinant.