Deoxyribonucleic acid. Model Crick futhi Watson

Ulwazi lokuqala mayelana izakhiwo amakhemikhali deoxyribonucleic acid ezangesikhathi ngonyaka 1868. Ekhulwini lama-20 kuya ekuqaleni forties, kwakutholakala ukuthi molecule polymer komugqa. Njengoba monomer amayunithi isenzo nucleotide ukuthi siqukethe base-nitrogen, a pentose futhi iqembu phosphate (ushukela ezinhlanu-carbon).

Deoxyribonucleic acid ungase ube phansi izinhlobo ezimbili: a pyrimidine (thymine (T) ne-cytosine (C)) kanye purine (i-adenine (A) futhi i-guanine ne (G)). Egcekeni Kwenziwa usebenzisa nucleotide phosphodiester isibopho.

Izazi zezinto eziphilayo Watson Crick unyaka 1953, ukuthatha njengesisekelo -X-ray ukuhlaziywa amakristalu DNA baphetha ngokuthi i-molecule ye bomdabu siqukethe yebhangqa amaketanga polymer, ukwakha double helix. Polynucleotide uchungechunge isilonda nomunye, aphethwe ndawonye ngezindlela hydrogen izibopho ukuthi yakha phakathi aphelele (Okusizayo okuhambisanayo) elisekela ngamaketanga okuphambene. Uma lokhu pair kwakhiwa kuphela kanje: i-adenine-thymine, i-guanine ne-cytosine. Ukuqina Kwenziwa amabhangqa amabili lokuqala nelesibili - hydrogen izibopho ezintathu.

I kabili balahleke deoxyribonucleic acid has a obuphelele esibaliwe inani namabhuzu nucleotide Okusizayo esihambisanayo (BP). Ukuze kwakheke lawo mangqamuzana okuyinto aqukethe izigidi nezinkulungwane amayunithi imibhangqwana m.n.p. kuthathwe futhi kb, ngokulandelana. Ngakho, deoxyribonucleic chromosome acid imelelwa eyodwa double helix. Ubude bayo 263 Mb e

DNA denaturation (ukuncibilika) kuyinqubo lapho ejwayelekile double Helix komugqa-molecule ludlulele ngaphakathi isimo ikhoyili. Lapho ukuncibilika, kabili i-molecule sehlukaniswe wesifunda ehlukile. Amazinga lapho isigamu deoxyribonucleic acid elicibilikile, a lokuncibilika. It kuncike izinga ukwakheka kwama-molecule.

Njengoba sekushiwo ngenhla, G-C ngababili Ukuzinziswa ezintathu, kanye pair of A-T - izibopho ezimbili ze-hydrogen. Ngakho, ayanda Ingxenye ngazimbili lokuqala, ezinzile kuyoba engqamuzaneni. Lapho denaturation ka inamandla 260 nm kwandisa ukumuncwa ukukhanya. Lo mphumela hyperchromic kwenza kube nokwenzeka ukunikeza ukulawula isimo yamangqamuzana isakhiwo yesibili. Uma isixazululo kancane selehlile oncibilikisiwe acid phakathi imicu ayahambelana izixhumanisi ababuthakathaka zingase zimiswe futhi, kungaba isakhiwo Kuvunguza nsé bomdabu (wokuqala). Leli khono le-DNA denaturation futhi renaturation molecule based hybridization indlela. Isetshenziselwa ekutadisheni isakhiwo of acid nucleic.

Kabili Helix molecule kokuba esiphathiswa idatha zofuzo, kunamaphuzu amabili okufanele acatshangelwe main. Okokuqala, kufanele ziphindaphindwe (ovezwe) ngokunemba high, futhi okwesibili, ukuze encode synthesis amaprotheni molecule. -Deoxyribonucleic acid, okuyinto imodeli ziye zachaza Watson Crick, elihambela- nalezi zimfuneko. Litholakala ukuthi ngokuhambisana isimiso complementarity, uchungechunge ngamunye engqamuzaneni kungaba matrix ekwakhekeni wesifunda omusha Okusizayo elihambisana. Ngenxa yalokho, omunye esiteji of ukufanisana ngaleyo ndlela kwenzeka ubhanqe indodakazi molecule kokuba ukulandelana nucleotide nsé nalezo yokuqala DNA. Ngaphezu kwalokho, lolu chungechunge isakhi sofuzo ezihlelekile okubhalwe amaprotheni amino acid ukulandelana usetha.

Njengoba, njengoba lwenziwe ukuvulwa DNA zomphakathi kanye complementarity isimiso, izinqubo luthole ukuthi banesibopho idatha emagama zenani elikhulu eziyifa kanye e ukulawulwa isakhi sofuzo zamagama izinto. Ngaphezu kwalokho, imfundiso yokuziphendukela yasungulwa futhi amangqamuzana isakhi sokuzakhela.