Ukulungiswa: yini lena? DNA ukulungisa izindlela

Ukulungiswa - ophilayo cell impahla ukubhekana ezihlukahlukene ukulimala kwe-DNA. Emhlabeni ngaphandle kukhona izinto eziningi ezingabanga izinguquko ezingenakuhlehliswa eziphilayo. Ukuze silondoloze ubuqotho babo, ukugwema ukushintsha izakhi zofuzo okuqondiswa sokugembula futhi akuhambisani ngempilo, kumelwe kube khona uhlelo self-yokutakula. Njengoba kwephule ubuqotho izinhlayiya eziyisisekelo zofuzo yeseli? Cabanga ngalo mbuzo kabanzi. Futhi, uthole ukuthi yini ningumzimba sika ukulungisa izindlela nokuthi asebenza kanjani.

Kwezinso ku-DNA

Deoxyribonucleic acid-molecule kungenzeka abaphukile inkambo biosynthesis kanye bedle izidakamizwa eziyingozi. Phakathi kwezici negative, ikakhulukazi, zihlanganisa izinga lokushisa noma amandla ngokomzimba Lokudabuka ezahlukene. Uma ukwa iphutha, iseli ukulungiswa nqubo iqale kabusha. uyiqala kanjalo nokubuyiselwa isakhiwo yokuqala molecule ye-DNA. Ukuze ukulungiswa ukuhlangabezana enzyme izakhiwo ezithile okukhona ngaphakathi amaseli. Njengoba ukungakwazi amangqamuzana ngamanye lokufeza ezinye yokutakula ezihlobene nesifo. Isayensi ukuthi etadisha izinqubo kokulungiswa, - kuyinto biology. Ngaphakathi isiyalo kwenziwe okuningi ukuhlolwa futhi ucwaningo, ngenxa okuyinto kuba lula ukuqonda inqubo yokutakula. Kumele kuqashelwe ukuthi le miklamo ukulungiswa DNA Ziyathakazelisa, njengoba umlando ukutholakala kanye cwaningo zalesi simo. Yiziphi izici eziwumthelela ekuqaleni yokutakula? Ukuze uqale inqubo, kubalulekile ukuthi DNA stimulator abathintekayo izicubu ukukhanda. Kuyini, achaza ngezansi.

Umlando yokutholakala

Lesi simo esiyingqayizivele sibangelwa isimanga waqala ukutadisha American Usosayensi Kellner. Ukutholakala sokuqala esibalulekile uhambo ukuhlola ukulungisa isibe into ezifana photoreactivation. Lokhu Waiter eside ngokuthi ingozi ukuncishiswa umphumela UV ngemisebe nangemuva iphathwa iseli abalimala elikhanyayo umfudlana ukukhanya we ebonakalayo emisebeni bohlu.

"Yokutakula Khanyisa"

Kamuva study Kellner got a ukuqhubeka esinengqondo ngemisebenzi izazi zezinto eziphilayo American Setlou, Rupert nabanye. Ngenxa yalo msebenzi lokhu iqembu lososayensi liye thembeke luthole ukuthi photoreactivation kuyinqubo eqalwa esikhethekile --enzyme catalyzes le cleavage ka-thymine dimers. Is they, kwacaca ukuthi, akhiwa phakathi ucwaningo ngaphansi kwe-ultraviolet. Ngakho kwaba nokukhanya okukhulu ebonakalayo umkhankaso isinyathelo of enzyme, okwathuthukisa cleavage ka dimers futhi abuyisele isimo sokuqala we izicubu ezonakele. Kulokhu sikhuluma ezihlukahlukene ukukhanya ukulungiswa DNA. Sichaza ngokucace kakhudlwana. Singasho ukuthi ukulungisa ukukhanya - is uzowubuyisela yasekuqaleni wadalula ekukhanyeni ngemva isakhiwo ukulimala kwe-DNA. Nokho, le nqubo hhayi kuphela iqhaza okuphambili indaba yokuqeda ukulimala.

"Isimo Esibucayi" yokutakula

Esikhathini esithile ngemva kuvulwa ukukhanya itholiwe ukulungisa amnyama. Lokhu kwenzeka ngaphandle umphumela imisebe yokukhanya bohlu ebonakalayo. Leli khono eliphawulekayo watholakala phakathi nesifundo nozwela amagciwane athile ukuze ultraviolet ray nakuma emisebeni ionizing. Dark ukulungisa DNA - ikhono amaseli ukususa noma yiziphi izinguquko pathogenic deoxyribonucleic acid. Kodwa-ke kumele ukuthi lena akuyona inqubo photochemical, ngokungafani kuya yokutakula ukukhanya.

Lo mshini "amnyama" Ukulimala lokuhlanza

Ukuqaphelwa amagciwane wabonisa ukuthi emva kwesikhathi esithize ngemva umzimba owumphumela wathola ingxenye ultraviolet, okuholela ezinye izingxenye DNA zalimala, iseli ulawula izinqubo zayo zangaphakathi ngendlela ethile. Ngenxa yalokho, i-DNA Ushintshe kumane ucezu elaqheshulwa uchungechunge ezivamile. I kwaphumela kabusha zigcwalise lezo zikhala we-amino acid izincwadi ezidingekayo. Ngamanye amazwi, wazithwala resynthesis ze-DNA. Ukuvulwa lososayensi into ezifana amnyama ukulungisa izicubu - lokhu kungesinye isinyathelo ukuhlola amazing amakhono ukuzivikela sesilwane kanye womuntu.

Kanjani uhlelo ukulungisa

Ukuhlolwa phendla izindlela alulame futhi ukuba khona kwezinceku leli khono, kwakwenziwa usebenzisa eziphilayo owumphumela. Kodwa izinqubo ukulungisa esivela kumaseli bezilwane nabantu abahlala. Abanye abantu uhlushwa xeroderma pigmentosum. Lesi sifo sidalwa ngokuntuleka ikhono amaseli resynthesize ezilimele DNA. Xeroderma ngofuzo. Kuyini uhlelo ukulungisa? Four-enzyme, okuyinto egcina inqubo ukukhanda - a DNA helicase, -ekzonukleaza, polymerase futhi -ligaza. Eyokuqala yalezi compounds uyakwati kubona ukulimala amangqamuzana uchungechunge deoxyribonucleic acid. It hhayi kuphela ibona, kodwa futhi enquma iketango endaweni efanele, ukususa kwesigaba engqamuzaneni ukushintshwa. ukususwa Idiphozithi Kwenziwa nge exonuclease DNA. Ngokulandelayo, ukuhlanganiswa kwezici ingxenye entsha deoxyribonucleic acid-molecule kusukela ama-amino acid sinombono esikhundleni ngokuphelele ingxenye obonakele. Awu Finale lokhu izinqubo eziyinkimbinkimbi begazi owazenza kuyi-enzyme-DNA ligase. Kuyinto unesibopho okunamathiselwe ingxenye ezilimele engqamuzaneni kwemiqondo. Uma konke enzyme ezine wenza umsebenzi omuhle, i-molecule ye-DNA is olusha ngokuphelele futhi wonke umonakalo ka esedlule. Lena yindlela ngokushelela ukusebenza izindlela amangqamuzana aphilayo.

ngezigaba

Kuleli qophelo, izazi ziye zakhomba lezi zinhlobo ezilandelayo ukulungisa izinhlelo. Basuke isebenze kuye ngamaphuzu ezahlukene. Lezi zihlanganisa:

1. Ukuvuselelwa.
2. Recombination yokutakula.
3. Ukulungisa of heteroduplexes.
4. Excision ukulungisa.
5. I kokuhlanganiswa izingqinamba-non-homologous ka molecule e-DNA.

Zonke izinto eziphilayo owumphumela enezimiso okungenani ezintathu enzymatic. Ngamunye wabo unekhono ukusebenzisa inqubo yokutakula. Lezi izinhlelo zibandakanya: oqondile, excision futhi postreplicative. Izinhlobo ezintathu ukulungisa DNA babe prokaryotes. Kepha eukaryotes, kuba ayenazo, izindlela ezengeziwe, ababiziweyo Miss-Mathe futhi Sos-ukulungisa okuthile. Biology bahlola ngokuningiliziwe zonke lezi izinhlobo self-ukuphulukiswa izinhlayiya eziyisisekelo zofuzo amaseli.

Ukwakheka izindlela ezengeziwe

ukulungisa Direct - kuyindlela okungenani eyinkimbinkimbi yama ukususa izinguquko sokugembula kuyi-DNA. It wenziwa enzyme ethize. Siyabonga kubo, ukubuyiselwa isakhiwo se-molecule ye-DNA kuyashesha kakhulu. Ngokuvamile, le nqubo wabe ngesinyathelo esisodwa. Omunye enzyme ngenhla O6-methylguanine-DNA methyltransferase. Excision uhlelo ukulungisa - lena uhlobo self-ukuphulukiswa-deoxyribonucleic acid, okubandakanya ukusika ukuthi ukushintshwa amino acid, futhi esikhundleni alandelayo amasayithi abo kabusha kwemiqondo. Le nqubo ibizwa eyenziwa ngezigaba eziningana. Phakathi postreplicative DNA wokulungisa isakhiwo zale molecule kungase elasungulwa value igebe chain. Khona-ke alivala iqhaza RecA amaprotheni. Postreplicative uhlelo ukulungisa uhlukile inqubo yayo sintula isigaba ukuthola izinguquko pathogenic.

Ubani obhekene nomsebenzi lo mshini yokutakula

Kuze kube manje, ososayensi bayazi ukuthi isidalwa elula, njengabo E. coli, ayinakho esingaphansi amahlanu izakhi zofuzo ngqo ukuze lilungiswe. isakhi ngasinye has yemfanelo ethile. Lezi zihlanganisa: ukuthola, ukususwa, zamagama, okunamathiselwe, ukuhlonza imiphumela emisebe yama-UV, nokunye. Ngeshwa, iyiphi zezakhi zofuzo, kuhlanganise nalezo ezingasebenzisi banesibopho izinqubo ukulungisa kuseli, ngaphansi izinguquko mutational. Uma lokhu kwenzeka, khona-ke ukushintsha izakhi zofuzo okuqondiswa zivula njalo ngaphezulu zonke emangqamuzaneni omzimba.

I esiyingozi ukulimala kwe-DNA

Nsuku zonke, i-DNA yezakhi umzimba amangqamuzana amehlo ethu okuthiwa zisengozini yokungenwa umonakalo kanye nezinguquko sokugembula. Lokhu lula okuthonywa nayizimo zendawo ezifana emisebeni yelanga, izithasiselo zokudla, amakhemikhali, lokushisa ukweqisa, amandla kazibuthe, izingcindezi eziningi ukuthi iqale izinqubo ezithile emzimbeni, nokuningi. Uma sinqamukile isakhiwo DNA, umuntu angaba kuguquka amaseli ezinzima futhi kungaholela kumdlavuza esikhathini esizayo. Yingakho umzimba kuyinto eyinkimbinkimbi izinyathelo zokubhekana nesimo esikuso ukulimala ezinjalo. Ngisho noma uketshezi abakwazi ukubuyela ukubukeka yokuqala DNA, uhlelo ukulungisa siveza ukugcina ukulimala ubuncane.

recombination homologous

Sizokwenza siyiqonde ukuthi iyini. Recombination kuyinto exchange nesidoda okunikelwe esikhaleni nemisho lemagalagala molecule deoxyribonucleic acid. Esimweni lapho kukhona amakhefu ku-DNA, homologous recombination inqubo iqala. Phakathi ke kushintshwa izingcezwana zishintshe ezimbili. Nale abuyiselwe ngokunembile isakhiwo yokuqala deoxyribonucleic acid. Ukungena kwe-DNA singenzeka kwezinye izimo. Ngokusebenzisa inqubo recombination kungenzeka ukuhlanganisa izinto ezimbili ezingefani.

Mshini zokululama lomzimba impilo

I ukulungisa - ke kungokudingekayo we ukusebenza evamile umzimba. Kungenzeka ukuthi ukuphathwa nsuku zonke futhi izinsongo ngehora ukulimala kwe-DNA futhi ukuguquka kwezakhi zofuzo, isakhiwo ezinamangqamuzana amaningi uvuma futhi uyasinda. Lokhu kwenzeka futhi ngenxa ohlelweni oluthile olumisiwe ukulungisa. Ukuswelakala kokusebenza ngokuhlanganyela nokuqinisela evamile kubangela kuguquka ezifweni nakwezinye kwezinso. Lezi zihlanganisa ezihlukahlukene zokugula, Oncology ngisho yokuguga ngokwayo. izifo Ukubambezeleka ngenxa yokuphazamiseka ukulungiswa kungaholela izimila abulalayo ezinzima nezinye kwezinso umzimba. Manje ezikhonjwe izifo ezithize kubangelwa efanele kuyinto DNA ukulungisa izinhlelo. Lezi, isibonelo, izifo ezifana Cockayne syndrome, xeroderma, nonpolyposis umdlavuza colon, Trichothiodystrophy kanti ezinye izinhlobo zomdlavuza.