Nowokunceda: yintoni le nto? iindlela ukulungisa DNA

Nowokunceda - a ophilayo ipropati iseli ukujongana ezahlukeneyo umonakalo DNA. Kwihlabathi ngaphandle kukho izizathu ezininzi ezinokubangela utshintsho ezingenakuguqulwa ngayo izinto eziphilayo. Ukuze silondoloze ingqibelelo yabo, ukuze aphephe kwiDNA zophendlo lwezifo kwaye aluhambisani nobomi, kufuneka kubekho inkqubo self-wobuyiselo. Njengoko kuphula isidima genetic material yeseli? Qwalasela lo mbuzo ngokucacileyo ngaphezulu. Kwakhona, fumanisa ukuba yintoni na iindlela zokulungisa umzimba kwaye zisebenza njani.

Na ukungaqheleki kule DNA

Deoxyribonucleic acid molecule uya kwaphulwa ekuhambeni biosynthesis ngokunjalo phantsi kwempembelelo kwezinto eziyingozi. Phakathi izinto ezimbi, ingakumbi, iquka iqondo lobushushu okanye amandla emzimbeni imvelaphi ezahlukeneyo. Ukuba ezinjengokwaphuka kwenzeka, inkqubo nowokunceda iseli iqala. Utsho iqala ukubuyiselwa isakhiwo lokuqala molecule ye DNA. Kuba nowokunceda ukuhlangabezana izakhiwo enzyme ezithile abakhona phakathi kwiiseli. Ekubeni ukungakwazi iiseli ngamnye ukwenza ezinye izifo ehlobene. Isayensi lifunda iinkqubo ukulungiswa, - i ibhayoloji. Phakathi ingqeqesho wenziwe ezininzi iimvavanyo kunye amalinge, ngenxa leyo yenza kube lula ukuqonda inkqubo yokubuyisa ixesha ekuphulukenwe nalo. Kufuneka kuqatshelwe ukuba iindlela zokulungisa DNA umdla kakhulu, njengoko imbali lokubhaqwa nesifundo yale meko. Ziziphi izinto negalelo ekuqaleni kwakhona? Ukuqalisa inkqubo, kuyimfuneko ukuba DNA stimulator abachaphazelekayo ukulungisa kwithishyu. Yintoni na, ngakumbi uchaze ngezantsi.

History of izovela

Le meko Akumangalisi waqalisa ukufunda yaseMelika Scientist Kellner. Kubaluleke kakhulu ukufunyanwa lokuqala ezibalulekileyo uhambo ukulungiswa wokuhlola iye yaba into efana photoreactivation. Le umlungiseleli gama ngokuba nokunciphisa ingozi ifuthe UV zokukhanya post-ngayo iseli owenzakeleyo eqaqambileyo umsinga ukukhanya le radiation spectrum ebonakalayo.

"Recovery Ukukhanya"

Kamva Uphanda Kellner wafumana nokuqhubekeka ubhalo ngemisebenzi zebhayoloji American Setlou, Rupert kunye nabanye. Ngenxa umsebenzi weli qela izazinzulu sele ngokuthembekileyo yasekwa ukuba photoreactivation yinkqubo uqalwa into ezikhethekileyo - enzayimi catalyzes i cleavage of dimers thymine. Ngabo, njengokuba kanti, kwasekwa ngethuba yemifuniselo phantsi kweultraviolet light. Ngoko ke ukukhanya okuqaqambileyo ebonakalayo usungule ntshukumo enzyme, nto leyo ekhuthaza cleavage of dimers abuyisele imeko lokuqala esikule yonakele. Kule meko sithetha ezahlukeneyo ukukhanya nokulungiswa DNA. We bakuchaza ngokucacileyo ngakumbi. Sinokuthi ukuba wokulungisa ukukhanya - ulibuyele original boniswa ukukhanya emva isakhiwo umonakalo DNA. Nangona kunjalo, le nkqubo igalelo kuphela ekupheliseni yokwenzakala.

"Dark" wobuyiselo

ixesha elithile emva kokuvulwa ukukhanya ibhaqwe wokulungisa emnyama. Oku kwenzeka ngaphandle nefuthe reyi ukukhanya spectrum ebonakalayo. Le nokomelela eyafunyanwa ngethuba lophando uvakalelo iintsholongwane ezithile ukuze yelanga eyingozi kunye radiation ionizing. Dark DNA yokulungisa - ukukwazi weseli asuse naluphi na utshintsho yayintsholongwane eyosulela deoxyribonucleic acid. Kodwa ke kufuneka ke ukuba le yinkqubo nomsi, ngokuchaseneyo ngokubhekiselelwe ukukhanya.

Indlela of "mnyama" Umonakalo Cleanup

Kokuma iintsholongwane lwabonisa ukuba emva kwexesha elithile emva kokuba eyodwa ezineseli wafumana inxalenye yiultraviolet, nto leyo amanye amacandelo DNA ziye zonakaliswa, iseli silawula iinkqubo zayo zangaphakathi ngendlela ethile. Ngenxa yoko, i-DNA iguqulwe nje isiqwenga liqhephuka chain eqhelekileyo. Kubangela kwakhona ukuvala izikhewu ye-acid asidi izinto eziyimfuneko. Ngamanye amazwi, wazithwala resynthesis ye DNA. Ukuvulwa izazinzulu into ezifana mnyama ukulungisa inyama - oku elinye inyathelo siphonononga amangalisayo ngoyaba le isilwanyana kunye nabantu.

njani indlela yokulungisa

Amalinge phendla iindlela ukubuyiselwa kunye kwankqu ubukho eli khono, zenziwa kusetyenziswa eziphilayo olunye-ezineseli. Kodwa neenkqubo ukulungiswa ezendeleyo iiseli kwezilwanyana nabantu abaphilayo. Abanye abantu bayahlupheka ukusuka xeroderma pigmentosum. Esi sifo sibangelwa ngokungabikho isakhono iiseli resynthesize ezonakeleyo DNA. Xeroderma ilifa. Yintoni na inkqubo yokulungisa? Four enzyme, leyo igcina inkqubo yokulungisa - DNA helicase, -ekzonukleaza, polymerase kunye -ligaza. Eyokuqala ezi zihlanganisi uyakwazi ukunakana umonakalo molekyuli chain of deoxyribonucleic acid. Uvumela nje kuphela, kodwa usika chain endaweni elungileyo, ukususa kwicandelo kwemolekyuli ilungiswe. ukususwa idipozithi lwenziwa nge exonuclease DNA. Emva koko, lo Yindibanisela isabelo elitsha deoxyribonucleic acid molecule evela acid ngenjongo endaweni ngokupheleleyo umbuzo eyonakeleyo. Well finale le iinkqubo ezintsonkothileyo eziphilayo Zenziwe enzayim DNA ligase. It unoxanduva uncamathiselo kwi isahlulo umonakalo kwemolekyuli kuhlelwe. Xa zonke ezine enzymes benze umsebenzi wabo, kwemolekyuli iDNA iyahlaziywa ngokupheleleyo kwaye zonke umonakalo elidlulileyo. Oku yindlela kakuhle iindlela zokusebenza ezikwiiseli eziphilayo.

ngezigaba

Kweli nqanaba, izazi ziye ezi ntlobo zilandelayo lweenkqubo ukulungiswa. Bona kusebenze kuxhomekeke ezintweni ezahlukeneyo. Ezi ziquka:

1. Ephinde.
2. alulame Recombination.
3. Ukulungiswa heteroduplexes.
4. Ukusikwa yokulungisa.
5. Begazi luphela non-homologous neemolekyuli DNA.

Zonke eyodwa enye babe iinkqubo ubuncinane ezintathu enzymatic. Ngamnye kubo uyakwazi ukuphumeza inkqubo yokubuyisa ixesha ekuphulukenwe nalo. Ezi nkqubo ziquka: ngqo, Ukusikwa kunye postreplicative. Iintlobo ezintathu yokulungisa DNA babe prokaryotes. Yona eukaryotes, oko zokulenza, iindlela ezongezelelweyo, leyo ibizwa ngokuba uMiss-Mathe kunye Sos-nokulungisa. Biology yahlola ngokweenkcukacha zonke ezi iintlobo self-ukuphiliswa impahla yemfuza iiseli.

Ulwakhiwo iindlela ezongezelelweyo

nokulungiswa ngqo - yindlela ubuncinane elinzima ukubatshabalalisa utshintsho zophendlo lwezifo kwi DNA. Oku enzyme ezithile wenziwe. Enkosi kubo, nokubuyiselwa ubume kwemolekyuli DNA akakhawulezi kakhulu. Ngokubanzi, uhlelo kwinyathelo elinye. Enye i-enzayim ngasentla O6-methylguanine-DNA methyltransferase. inkqubo yokulungisa Ukusikwa - oku uhlobo self-ukuphiliswa deoxyribonucleic acid, nto leyo ibandakanya ngokusika acid elungisiweyo, nokutshintshwa esilandelayo iziza zabo kwakhona kuhlelwe. Le nkqubo luqhutywa ngokwamabakala eziliqela. Ngexesha postreplicative DNA wokulungisa isakhiwo sale molecule ukuba abunjwe kwikhonkco ixabiso isikhewu. Emva koko ke ivalwe kunye inxaxheba RecA protini. inkqubo yokulungisa Postreplicative ukhetheke kuloo nkqubo yayo uswele kwisigaba silubone utshintsho izifo.

Ngubani onoxanduva yindlela ekuphulukenwe nalo

Ukuza kuthi ga ngoku, oosonzululwazi siyazi ukuba sidalwa elula, njengabo E. coli, uye iijini kungekho ngaphantsi kwe amahlanu ngqo ukuze ilungiswe. isakhi ngasinye linoxanduva oluthile. Ezi ziquka: Ubhaqo, ukususwa, kuyondelelaniswe, ulwalamano, ukuphawulwa imiphumela rays UV, njalo-njalo. Ngelishwa, naziphi na iijini, kuquka abo banoxanduva kwiinkqubo wokulungisa esiseleni, phantsi utshintsho mutational. Ukuba oku kuyenzeka, ngoko ziqala ukuguquka lwaqho kuzo zonke iiseli zomzimba.

I-DNA umonakalo eyingozi

Yonke imihla, i-DNA ye iiseli zethu zomzimba basemngciphekweni umonakalo kunye notshintsho zophendlo lwezifo. Oku lula neemeko zokusingqongileyo ezifana ultraviolet radiation, ongeziweyo ukutya, amachiza, bazifake ubushushu, zibuthe, neengxaki ezininzi umkhwetha iinkqubo ezithile emzimbeni, kwaye ngaphezulu. Ukuba isakhiwo iDNA yophukile, oko kunokubangela iiseli kakhulu wezakhi kwaye kunokukhokelela kumhlaza kwixesha elizayo. Kungenxa yoko le nto yinto nje oluntsonkothileyo amanyathelo ukujongana ukonzakala ezinjalo. Nokuba enzyme ayikwazanga ukubuyela inkangeleko yokuqala DNA, inkqubo yokulungisa isebenza ngaphandle ukugcina umonakalo ubuncinane.

recombination homologous

uya siqonde ukuba yintoni na. Recombination yi utshintshiselwano genetic material ethubeni kunye nambaxa molecule deoxyribonucleic acid. Kwimeko apho kukho amakhefu DNA, inkqubo recombination homologous iqala. Ngexesha kokuba banikana iingceba iimolekyuli ezimbini. Nale ngokuchanileyo wambuyisela isakhiwo lokuqala deoxyribonucleic acid. ukungena ye DNA ezinokwenzeka kwezinye iimeko. Ngokusebenzisa inkqubo recombination kunokwenzeka ukuze kumanyaniswe zonke iinkalo ezimbini ezahlukeneyo.

Indlela of kwakhona umzimba nempilo

I ukulungisa - kuyimfuneko ukuba eqhelekileyo yokusebenza komzimba. Báthi imihla nezisongelo ngeyure umonakalo DNA kunye zofuzo, isakhiwo multicellular akufundisayo kwaye iphila. Oku kwenzeka kwakhona ngenxa inkqubo yokulungisa lusekiwe. Ukungabikho wokomelela oluqhelekileyo kubangela ukuguquka isifo kunye nezinye ezingaqhelekanga. Ezi ziquka iindidi ngezifo, Oncology kunye nokuguga ngokwayo. izifo ilifa ngenxa ukuphazamiseka kwendlela yokulungisa kunokukhokelela yamathumba kakhulu okubulalayo nezinye ezingaqhelekanga kumzimba. Ngoku ezichongiweyo izifo ezithile nokubangelwa iinkqubo ukulungisa DNA kakuhle na. Ezi, umzekelo, izifo ezifana Cockayne syndrome, xeroderma, nonpolyposis umhlaza colon, Trichothiodystrophy kunye ezithile zomhlaza.