Uyini-DNA, uyini umsebenzi walo nokubaluleka eziphilayo

DNA - a -deoxyribonucleic acid, esihlinzeka ukuphepha yokudlulisa ulwazi zofuzo. Ngo oyiyo ulwazi ngekhodi isakhiwo RNA namaprotheni zomzimba. Vula lesi sakhiwo Swiss I.Mishlerom ngo-1869.

Okokuqala, izakhiwo wangempela DNA bebelokhu engaziwa. Kukholakala ukuthi ubophezelekile ukunakekela umzimba phosphorus kanye izakhiwo zalo ukuze adlulisele ulwazi ngisho nokuwabona, ngoba abathwali Imininingwane lezinceku ngokwesiko kubhekwe amaprotheni. Kuphela ngo-1944, ngemva uchungechunge ucwaningo ekuguculweni kwamagciwane, kwatholakala ukuthi i-DNA enjalo, futhi ukubonakala imisebenzi yayo eziyisisekelo. Ngemva 1952 ulwazi mayelana ngale molecule wandisa - kwaziwa ukuthi esiphathiswa oyinhloko ulwazi mayelana nokwakheka genotype (isethi zofuzo i umzimba), kodwa wayengazi lutho ngesikhathi oyiyo kakhulu, isakhiwo DNA awuzange eloba.

isakhiwo kwama-molecule ayo ziqala ngo-1953 ngu-James Watson no-Francis Crick. Bona sinqume ukuthi lo DNA - molecule ye ukwakha Helix double ehlanganisa deoxyribose ne phosphate amaqembu, okubophela lezisekelo nitrogen - i-adenine, ne-cytosine, i-guanine ne ne-thymine.

Kufanele kuqashelwe ukuthi inhlanganisela zalezi zimiso has a inqubo echaziwe - i-adenine sibopha kuphela ihlangane ne-thymine futhi guanine ne-cytosine, iqinisekisa ilungile futhi olunembile self-ukufanisana ka molecule ye-DNA ngokuvumelana isimiso complementarity nomunye ezingaphansi kwayo ethandelayo.

a ukuhlonza okunjalo okucacile ukwakheka kwama-molecule ekwenzele ukuqonda kangcono lokho DNA - isakhiwo esilondoloza isimiso sezakhi zofuzo oluyisisekelo ufuzo kuzo zonke izinto eziphilayo, kuhlanganise eukaryotes kanti ezinye amagciwane.

Ikhodi zofuzo kugcinwa njengoba nucleotide thize. Ngakho, ngamunye amaprotheni amino acid okubhalwe ngu-nucleotide amathathu acid ukulandelana kuyinto zofuzo.

Uma kukhona izinguquko zenzeka isakhiwo DNA iphuzu kuguquka noma isakhi sofuzo. Point izinguquko mutational ku ukwakheka kwama-molecule kukhona ngenela, okulula ukuthola ukuhlaziywa kwamakhemikhali noma hybridological. Zofuzo zenzeka lapho kushintshwa nucleotide interleaving, okuyinto umphumela izinqubo ezifana nalesi, transversions, kufakwe noma ukulahleka ngabanye base ngazimbili, eziphula ukusebenza kanye izakhiwo ze-DNA.

Uma lezi zinguquko kwesakhiwo eziholela ukuhlanekezela izingxenye ezibalulekile we polypeptide e umzimba kukhona ukwephulwa komthetho okubi, enquma hhayi kuphela ukuhlukumeza ukuthuthukiswa eziphilayo, kodwa futhi ukubhujiswa kwabo. Ngokwesibonelo, ukuguqulwa kwezakhi zofuzo singenzeka ngisho phakathi kwengane esiswini, okubangela lokuzalwa izingane ezifile noma non-iphila. Ngaphezu kwalokho, komgomo ezinjalo bayinhliziyo kwabaningi kwasekuzalweni ezingase zidlulele ezizukulwaneni ezilandelayo.

Kufinyeta, kumele kuphetfwe njengoba i-DNA okungukuthi - kuba isakhiwo ebaluleke kakhulu ukwaziswa kwezakhi zofuzo, okuyinto ingxenye eyinhloko chromosome. Ngaphezu kwalokho, i-DNA - acid, okuyinto unomthwalo zisebenzise ulwazi zofuzo ukusebenza eziphilayo.