Reparation: yog dab tsi no? DNA kho mechanisms

Reparation - ib tug nyob ntawm tes tej khoom vaj tse mus nrog ib tug ntau yam ntawm DNA puas tsuaj. Nyob rau hauv lub ntiaj teb sab nraum muaj ntau ntau yam uas yuav ua rau irreversible hloov nyob rau hauv uas muaj sia nyob. Khaws cia rau lawv cov ntseeg, kom tsis txhob pathological change thiab incompatible nrog lub neej, yuav tsum muaj ib tug system ntawm yus tus kheej-rov qab. Raws li nws ua txhaum lub meej mom ntawm lub caj khoom ntawm tus xovtooj ntawm? Xav txog lo lus nug no nyob rau hauv ntau yam. Tsis tas li ntawd, nug seb puas yog lub cev kho mechanisms thiab yuav ua li cas lawv ua hauj lwm.

Kev txawv txav nyob rau hauv lub DNA

Deoxyribonucleic acid molecule tej zaum yuav tawg nyob rau hauv lub chav kawm ntawm lub biosynthesis raws li nyob rau hauv tus ntawm teeb meem tshuaj. Ntawm cov tsis zoo yam tseem ceeb, nyob rau hauv particular, muaj xws li cov kub los yog lub dag lub zog ntawm txawv keeb kwm. Yog hais tias qhov lov tshwm sim, lub cell reparation txheej txheem pib. Yog li pib lub restoration ntawm tus thawj qauv ntawm cov DNA molecule. Rau reparation raws li tej enzyme ceg uas tam sim no nyob rau hauv lub hlwb. Txij li thaum lub cev tsis muaj tug neeg lub hlwb mus nqa tawm ib co rov qab txuam kab mob. Cov science uas kawm cov txheej txheem kev kho, - yog biology. Tsis pub dhau cov kev qhuab qhia nqa tawm ntau heev ntawm kev ntsuam xyuas thiab thwmsim, vim uas nws yuav yooj yim rau to taub qhov rov qab txheej txheem. Nws yuav tsum tau muab sau tseg tias mechanisms ntawm DNA kho yog heev nthuav, raws li cov keeb kwm ntawm lub foundations thiab kawm txog qhov no phenomenon. Yuav ua li cas yam ua rau kom pib ntawm lub rov qab? Yuav pib li tus txheej txheem, nws yog tsim nyog tias DNA stimulator cuam tshuam cov ntaub so ntswg kho. Yuav ua li cas yog nws, ntau piav rau hauv qab no.

Keeb kwm ntawm foundations

Qhov no ceeb tshwm sim pib kawm American paub txog Kellner. Tus thawj tseem ceeb foundations rau ib tug taug kev mus ntawm kev tshawb kawm kho tau ua xws li ib tug tshwm sim raws li photoreactivation. Qhov no lub sij hawm Waiter hu ua raug mob yuav txo tau cov nyhuv ntawm UV irradiation thiab post-kho mob cell kaj kwj ntawm lub teeb ntawm qhov pom spectrum tawg.

"Lub teeb rov qab"

Tom qab ntawd kawm Kellner tau txais ib zajlus kom continuation nyob rau hauv tej hauj lwm ntawm American biologists Setlou, Rupert thiab ib co lwm tus neeg. Ua tsaug rau cov ua hauj lwm ntawm no pab pawg neeg ntawm zaum tau nti tsim hais tias photoreactivation yog ib tug txheej txheem uas yog pib los ntawm ib tug tshwj xeeb tshuaj - ib qho enzyme uas catalyzes lub cleavage ntawm thymine dimers. Nws yog lawv leej twg, raws li nws muab tawm, raug tsim nyob rau hauv lub chav kawm ntawm lub thwmsim nyob rau hauv ultraviolet lub teeb. Yog li ib tug kaj pom lub teeb launched kev txiav txim ntawm lub enzyme, uas nce cleavage ntawm dimers thiab rov qab kho cov thawj mob ntawm lub puas cov ntaub so ntswg. Nyob rau hauv cov ntaub ntawv no peb yuav tham txog ib lub teeb ntau yam ntawm DNA kho. Peb txhais tau tias nws ntau kom meej meej. Peb yuav hais tias qhov teeb kho - yog es ua kom cov thawj raug mus rau lub teeb tom qab cov qauv ntawm cov DNA puas tsuaj. Txawm li cas los, txoj kev no tsis yog tsuas pab rau cov tshem tawm ntawm kev raug mob.

"Tsaus" rov qab

Tej lub sij hawm tom qab qhib ntawm lub teeb twb ntes tau tsaus ntuj nti kho. Qhov no tshwm sim tshwm sim uas tsis muaj cov nyhuv ntawm lub teeb rays ntawm qhov pom spectrum. Qhov no resilience twb pom thaum lub sij hawm kawm cov kev rhiab heev ntawm tej yam kab mob rau ultraviolet rays thiab ionizing tawg. Tsaus kho DNA - muaj peev xwm ntawm lub hlwb los tshem tawm tej pathogenic hloov deoxyribonucleic acid. Tab sis nws yuav tsum tau hais tias qhov no yog tsis yog ib tug photochemical txheej txheem, nyob rau hauv sib piv rau lub teeb rov qab.

Lub mechanism ntawm "tsaus ntuj nti" Puas yuav tu thiab tu

Tswvyim ntawm cov kab mob pom tias tom qab ib tug tej lub sij hawm tom qab ib leeg-celled kab mob tau txais ib feem ntawm cov ultraviolet, uas ua rau ib co seem ntawm DNA raug puas, cov cell regulates nws nrog dab nyob rau hauv ib txoj kev. Raws li ib tug tshwm sim, hloov DNA tsuas yog ib daim txiav los ntawm ib qho saw. Cov uas ua re-sau qhov khoob ntawm cov amino acids tsim nyog cov ntaub ntawv uas. Nyob rau hauv lwm yam lus, nws nqa resynthesis ntawm DNA. Qhib zaum li no tshaj plaws li tsaus ntuj nti kho cov ntaub so ntswg - qhov no yog lwm kauj ruam nyob rau hauv kawm ua tus amazing defensive muaj peev xwm ntawm cov tsiaj thiab tib neeg.

Yuav ua li cas puas muaj tus kho system

Sim kawm muaj ices mechanisms ntawm rov qab thiab cov heev hav zoov no muaj peev xwm, twb tau siv ib leeg-celled kab mob. Tab sis kho dab yog xam qhovkev nyob rau hauv nyob hlwb ntawm cov tsiaj thiab tib neeg. Ib txhia neeg raug kev txom nyem los ntawm xeroderma pigmentosum. Tus kab mob no yog tshwm sim los ntawm ib tug tsis muaj lub peev xwm ntawm hlwb resynthesize puas DNA. Xeroderma pub. Ntawm dab tsi yog kho li cas? Plaub enzyme, uas yuav kho cov txheej txheem - ib tug DNA helicase, -ekzonukleaza, polymerase thiab -ligaza. Tus thawj ntawm cov tebchaw muaj peev xwm kom paub txog kev puas tsuaj rau lub saw molecules ntawm deoxyribonucleic acid. Nws tsuas tsis paub, tab sis kuj txiav cov saw hlau nyob rau hauv txoj cai qhov chaw, kom tshem tawm cov seem ntawm lub hloov molecule. Deposit tshem tawm yog nqa tawm nrog ib tug DNA exonuclease. Tom ntej no, lub synthesis ntawm ib tug tshiab feem ntawm deoxyribonucleic acid molecule los ntawm cov amino acids nrog ib tug saib kom tag yuav hloov tau cov puas ya. Zoo kawg no complex lom cov txheej txheem tau nrog ib tug DNA ligase enzyme. Nws yog lub luag hauj lwm rau lub Symptoms mus rau lub puas feem ntawm cov tsim qauv. Thaum tag nrho cov plaub enzymes tau ua lawv txoj hauj lwm, lub DNA molecule yog kiag li tshiab thiab tag nrho cov kev puas tsuaj ntawm yav dhau los. Qhov no yog yuav ua li cas ntseeg nkaws ua hauj lwm mechanisms hauv nyob hlwb.

kev faib

Thaum no tus taw tes, kws tshawb fawb tau pom cov nram qab no kho tshuab. Lawv tshuab txais nyob rau txawv yam. Cov muaj xws li:

1. Reactivation.
2. Recombination rov qab.
3. Kho ntawm heteroduplexes.
4. Excision kho.
5. Lub reunification uas tsis yog-homologous xaus ntawm DNA molecules.

Tag nrho ib leeg-celled kab mob muaj tsawg kawg yog peb enzymatic systems. Txhua yam ntawm lawv muaj peev xwm siv lub rov qab los txheej txheem. Cov systems muaj xws li: direct, excision thiab postreplicative. Lub peb hom ntawm DNA kho muaj prokaryotes. Raws li rau eukaryotes, nws yog nyob rau ntawm lawv pov tseg, ntxiv mechanisms, uas yog hu ua Miss-mathe thiab Sos-kho. Biology nais maum kuaj nyob rau hauv kom meej tag nrho cov hom ntawm nws tus kheej-zoo rau cov kev tshuaj ntsuam genetic khoom siv ntawm lub hlwb.

Qauv ntxiv mechanisms

Direct kho - nws yog ib lub kawg nyuab txoj kev ntawm tau txais tshem ntawm lub pathological kev hloov nyob rau hauv lub DNA. Nws yog nqa tawm ib qho enzymes. Ua tsaug rau lawv, kho tshiab ntawm cov qauv ntawm cov DNA qauv yog heev ceev ceev. Feem ntau, cov txheej txheem hais nyob rau hauv ib kauj ruam. Ib tug ntawm cov saum toj no enzymes yog O6-methylguanine-DNA methyltransferase. Excision kho system - qhov no yog lub hom ntawm nws tus kheej-kho ntawm deoxyribonucleic acid, uas yuav txiav tawm hloov amino acids, thiab tom ntej hloov ntawm lawv re-tsim qhov chaw. Qhov no txoj kev yog nqa tawm nyob rau hauv ob peb ua sawv. Thaum lub sij hawm postreplicative DNA kho nyob rau hauv cov qauv ntawm no molecule tej zaum yuav tsim nyob rau hauv ib tug kis tus nqi saw. Ces lawv kaw nrog kev koom tes ntawm RecA protein. Postreplicative kho system yog txawv nyob rau hauv hais tias nws cov txheej txheem lacks theem nrhiav kom tau ntawm pathogenic hloov.

Leej twg yog lub luag hauj lwm rau rov qab mechanism

Rau hnub tim, zaum paub hais tias xws li ib tug yooj yim zeej, zoo li E. coli, muaj tsis muaj tsawg tshaj li tsib caug noob ncaj qha rau kev kho. Txhua noob muaj tej yam dej num. Cov muaj xws li: nrhiav kom tau, tshem tawm, synthesis, Symptoms, kev qhia kom paub txog cov teebmeem ntawm UV rays, thiab hais txog. Tu siab, tej noob, xws li cov neeg uas yog lub luag hauj lwm rau kho dab nyob rau hauv lub cell, raug mutational hloov. Yog hais tias qhov no tshwm sim, ces lawv tso ntau heev change nyob rau hauv tag nrho cov hlwb ntawm lub cev.

Lub txaus ntshai kev puas tsuaj DNA

Txhua txhua hnub, tus DNA ntawm peb lub cev hlwb muaj teeb meem ntawm kev puas tsuaj thiab pathological kev hloov. Qhov no yog facilitated los ntawm ib puag ncig yam tseem ceeb xws li ultraviolet hluav taws xob, khoom noj khoom haus additives, tshuaj, kub extremes, magnetic teb, heev heev txhawj xeeb uas pib tej dab nyob rau hauv lub cev, thiab ntau dua. Yog hais tias cov DNA qauv yog lawm, nws yuav ua rau mob loj heev hloov hlwb thiab yuav ua tau kom mob cancer nyob rau hauv lub neej yav tom ntej. Uas yog vim li cas hauv lub cev yog ib tug complex ntawm kev ntsuas mus rau nrog xws kev raug mob. Txawm yog hais tias tus enzymes tsis muaj peev xwm rov qab mus rau tus thawj tsos ntawm DNA, kho system ua hauj lwm tawm mus rau kom puas tsuaj mus rau ib tug tsawg kawg nkaus.

homologous recombination

Peb yuav to taub li cas nws yog. Recombination yog ib qho kev pauv ntawm kev tshuaj ntsuam genetic khoom nyob rau hauv cov kis thiab compound molecules ntawm deoxyribonucleic acid. Nyob rau hauv lub rooj plaub uas muaj so nyob rau hauv lub DNA, homologous recombination txheej txheem yuav pib. Thaum lub sij hawm nws yog exchanged tawg tsam ntawm ob molecules. Nrog rau qhov no meej rov qab los thawj cov qauv ntawm deoxyribonucleic acid. allergic ntawm cov DNA yuav tshwm sim nyob rau hauv tej rooj plaub. Los ntawm tus txheej txheem ntawm recombination yog ua tau rau integrate ob tug sib txawv ntsiab.

Lub mechanism ntawm rov qab los ntawm lub cev thiab kev noj qab nyob

Lub kho - nws yog ib tug yuavtsum tau kawm uantej ntawm lub cev tau hauj lwm ntawm lub cev. Raug rau txhua txhua hnub thiab teev ntshai heev txawm DNA puas tsuaj thiab change, multicellular qauv adapts thiab cawm. Qhov no tshwm sim kuj vim ib tug tsim kho system. Qhov uas tsis muaj dab tsi resilience ua tus kab mob hloov thiab lwm yam txawv txav. Cov no muaj xws li ib tug ntau yam ntawm pathology, Oncology thiab txawm laus nws tus kheej. Mob muaj keeb kab mob vim teeb ntawm kho yuav ua tau rau mob phem hlav thiab lwm yam kev txawv txav ntawm tus kab mob. Tam sim no pom tias tej yam kab mob tshwm sim los ntawm ua hauj lwm yog DNA kho tshuab. Cov no yog cov, piv txwv li, cov kab mob zoo li Cockayne syndrome, xeroderma, nonpolyposis nyuv mob cancer, Trichothiodystrophy thiab ib co qog nqaij hlav.