Iqhubekekisa - is ... RNA processing (post-transcriptional RNA ukulungiswa)

It eyenza eli nqanaba ukuphunyezwa imizila yemfuza iiseli ezifana eukaryotes kunye prokaryotes ezikhoyo.

Ukutolikwa le ngcamango

E IsiNgesi, eli gama lithetha "unyango, ziphilise." Iqhubekekisa - lo ukuyilwa iimolekyuli RNA oqolileyo ukusuka pre-RNA. Ngamanye amazwi, le uluhlu esisabela ezikhokelela inguqu imveliso Ukuloba ephambili (pre-RNA kweentlobo ezahlukeneyo) ngendlela molecule sele-ezisebenza.

Ngokumalunga ukuhluzwa p- kunye tRNA, oko kudla zehla ukuba ngokunqamla iziphelo molekyuli amaqhekeza ezingaphezulu. Ukuba sithethe mRNA, ukuze kuqatshelwe apha ukuba eukaryotes, inkqubo ithatha kuqhubeka ngokwezigaba eziliqela.

Ngoko ke, emva kokuba sele sifundile ukuba inkqubo - i inguqu okotshiweyo zaseprayimari zibe le RNA molecule aqolileyo, kufuneka uqhubeke ukuze kuqwalaselwe iimpawu zayo.

Ezona mpawu ziphambili le mbono

Oku kunokuquka oku kulandelayo:

• ukuguqulwa zombini iziphelo molecule kunye RNA, ngexesha apho uncediswa ulandelelwano nucleotide ethile abonisa indawo ekuqaleni (ekupheleni) zosasazo;
• usifake - clip ulandelelwano acid ribonucleic uninformative leyo ezihambelana DNA introns.

Ke prokaryotes, bona abawuthobeli processing mRNA. Kuye ukukwazi ukusebenza ukususela ekupheleni ehlaziya.

Apho ophuma inkqubo umbuzo?

Nayiphi processing ephilayo RNA ithatha indawo ngumongo. It ikhutshwa phandle enqanda ezithile (Iqela zazo) ukuba ngamnye uhlobo iimolekyuli. ukuqhubekekiswa kwakhona ukuba lungakhuseleki kwi iimveliso inguqulelo ezifana polypeptides aleswayo ngqo kwi mRNA. Ezi utshintsho kuxhomekeke ebizwa ngokuba iimolekyuli siphu- iiprotheni ezininzi - collagen, izilwa-buhlungu, enzyme, ezinye iihomoni, uze emva koko iqalisa ukusebenza kanye umzimba.

Sele sifundile ukuba inkqubo - lo ukuyilwa RNA oqolileyo ukusuka pre-RNA. Ngoku kuyimfuneko ukuba sijonge uhlobo koninzi ribonucleic acid.

RNA: uhlobo khemikhali

Le ribonucleic acid, nto leyo copolymer of pyrimidine kunye purine ribonukleitidov abaqhagamshelwe omnye komnye, kanye njengokuba i-DNA 3 '- kwo 5'-phosphodiester.

Nangona isibakala sokuba ezi ntlobo zimbini ze iimolekyuli ezifanayo, ahluke ngezizathu ezininzi.

Izimilo RNA ne-DNA

Okokuqala, ribonucleic acid ekhoyo kwi intsalela carbon apho abut pyrimidine kunye purine neenqwelwana, iqela phosphate - ribose, e-DNA efanayo - 2'-deoxyribose.

, Amacandelo ahlukeneyo weSibini pyrimidine. amacandelo ezifanayo ezi nucleotides adenine, cytosine, guanine. Xa RNA, uracil ekhoyo endaweni thymine.

Okwesithathu, RNA 1 isakhiwo chain, kunye DNA - 2-ethungelanayo molecule. Kodwa ribonucleic acid umcu iinxalenye ezikhoyo wokwephuka malungana (ulandelelwano edibanayo) apho ikwazi umxokelelwane elilodwa ihlwili ukwenza "jiko" - isakhiwo, sanikwa iimpawu isantya-2 (njengoko kubonisiwe ngentla).

Okwesine, ngokuba RNA - nomxokelelwane enye, nto leyo Incedisa i mngxilo DNA yokuqala, guanine mfuneko nasiphi langoku kokuqulathwe efanayo njengoko cytosine kunye adenine - uracil oyithandayo.

Okwesihlanu, lo RNA ukuze hydrolyzed ngealkali 2 ', 3'-diesters of mononucleotides elibujikele. Indima haydrolisis eliphakathi ludlala 2 ', 3', 5-triester, akakwazi ukwenza ngexesha lenkqubo efanayo DNA ngenxa yokungabikho kumaqela zakhe 2'-hydroxyl. Xa kuthelekiswa DNA ialakalin lability of ribonucleic acid na ipropati luncedo iinjongo diagnostic, nangenxa uhlalutyo.

Ulwazi oluqulethwe kwi-RNA ndixakene-1 ngokubanzi luzalisekiswe njengoko kulandelelwano purine kunye pyrimidine neenqwelwana, oko kukuthi, i Polymer zaseprayimari isakhiwo chain.

Le ulandelelwano Incedisa chain gene (encoding), awanyakazela ngayo RNA "readout." Ngenxa kule impahla ribonucleic acid molecule Unga bophelela ngokukodwa ikhonkco ikhowudi, kodwa aninako ukwenza oku non-ikhowudi DNA imicu. ulandelelwano RNA, ngaphandle sithatha T U, efana naleyo ebhekiselele non-ikhowudi chain sofuzo.

iintlobo RNA

Phantse bonke ababandakanyeka kwinkqubo ezifana protein biosynthesis. lweendidi ezaziwayo RNA:

1. Matrix (mRNA). Oku cytoplasmic iimolekyuli acid ribonucleic zisebenzayo matrices protein yokuqaphela.
2. Ribosomal (rRNA). Le RNA molecule cytoplasmic, sikhonza amacandelo zokusebenza ezifana ribosomes (organelles ababandakanyekayo ngakwicala leeprothini yokuqaphela).
3. Zokuhamba (tRNA). Oku molekyuli zothutho asidi ribonucleic aqukiweyo ulwazi translation (translation) mRNA ibe kulandelelwano asidi acid kwi iiprotheni kakade.

Inxalenye enkulu ye-RNA ye iitranskripthi zodliwano yokuqala ziveliswa iiseli eukaryotic, kuquka iiseli mammalian, kudandalaza ngumongo kwinkqubo ukuthotywa, kwaye lidlala ulwazi kwi icytoplasm okanye indima noshowo.

Xa iiseli yabantu (cultured) wafumana udidi asidi ezincinane yenyukliya ribonucleic ezingachazwanga ngqo inxaxheba ngakwicala leeprothini yokuqaphela, kodwa echaphazela processing RNA, kwakunye zizonke eyiselula "bokwakha." ubukhulu zabo ziyahluka, ukuba ziqulathe 90 - 300 nucleotides.

Ribonucleic acid - izinto ezisisiseko yemfuza ukusuka kwinani iintsholongwane izityalo kunye nezilwanyana. Ezinye iintsholongwane eziqulathe RNA, ungaze kudlula nyathelo njengoko reverse ye-RNA yaya kwi-DNA. Ukanti ngezifo ezininzi zezilwanyana, umzekelo Retroviruses, ebonakala ngu inguqulelo reverse genome RNA ngqo RNA-abaxhomekeke reverse (DNA polymerase) ukwenza ikopi DNA 2-helical. Kwiimeko ezininzi ukubonakala 2-helical DNA umbhalo yaziswa kwi genome sibonelele ngezinye amazwi yemfuza wentsholongwane egazini kunye nexesha lokusebenza lwe genomes ikopi RNA yakutsha (kunye nomthamo).

Izilungiso Post-transcriptional RNA

molecule zayo kuhlanganiswa kunye polymerases RNA, kusoloko ukukhula kwala maqalela abenemfundo engasebenziyo ukwenza, ezizezi pre-RNA. Bona ingaguqulwa njani na ibe molecule sele abaqolileyo kuphela emva kokuba kudlule iinguqulelo ezifanelekileyo post-transcriptional RNA - amanqanaba ekukhuleni kwayo.

Ukuqulunqwa aqolileyo mRNA wayefunde ngexesha kuyondelelaniswe kunye RNA polymerase II kwinyathelo zobude. Ngu 5'end ye ekhula ngokuthe ngcembe umcu RNA 5'end eqhotyoshelweyo GTP, ngoko anamathela orthophosphate. Ngaphezu koko, nokufika ethanol guanine 7-imethyl-GTP. Eli qela ethile, leyo yinxalenye mRNA, ebizwa ngokuba 'eswenyiweyo' (umnqwazi okanye ikepusi).

Kuxhomekeka RNA iintlobo (ribosomal kunye nezothutho, matrix, njalo njalo) uhlobo zithe zathotyelwa phantsi ulungiso ezahlukeneyo ezilandelelanayo. Umzekelo, ukuba uhlobo ezo spliced mRNA, kwesipirithi, capping, polyadenylation, kwaye maxa wambi nohlelo.

Eukaryotes: a isishwankathelo jikelele

iseli eukaryotic usebenza njengendawo izinto eziphilayo, kwaye iqulathe i kernel. Ukongeza iintsholongwane, archaea, zonke izinto ezo yenyukliya. Izityalo, nomngundo, izilwanyana, kuquka iqela eziphilayo, ekuthiwa protists - zonke izinto eziphilayo eukaryotic. Zombini-iseli 1 multicellular, kodwa zonke kwisicwangciso jikelele lobume yeselula. Kukholelwa ukuba ezi eziphilayo ezahlukeneyo benjenjalo imvelaphi efanayo, ngenxa yoko, iqela yenyukliya waqonda njenge taxon monophyletic abakuluhlu kakhulu.

Ngokusekelwe hypothesis othandwayo, eukaryotes zivelile 1.5 - 2 billion kwiminyaka eyadlulayo .. indima ebalulekileyo zazivelela lwabo unikwa symbiogenesis - ngokuncedisana iiseli eukaryotic, ebinezinto engundoqo ekwaziyo phagocytosis, amagciwane, Siyiginyile - eliphuma plastids kunye mitochondria.

Prokaryotes: iimpawu ngokubanzi

Le iseli-1 eziphilayo ukuba azinayo inucleus (registration), abaseleyo organelles inwebu (ngaphakathi). Kuphela enkulu DNA thunzi 2-chain molecule equka inxalenye enkulu ye-genetic material ye iseli enye okuyinto awakhi nezintsonkothileyo iiproteni histone.

Kuba prokaryotes ziquka archaea neentsholongwane, kuquka icyanobacteria. Inzala enucleated iiseli - organelles eukaryotic - plastids, mitochondria. Zahlula-hlulwe zohlaza 2 ngaphakathi elikwisikhundla idomeyini: Archaea neentsholongwane.

Ezi seli la mvulophu enyukliya, yahonjiswa iDNA lwenzeka ngaphandle ukubandakanywa histones. Osmotrofny uhlobo ukutya kwaye iqulethe umbandela yemfuza omnye yomoya DNA leyo uvaliwe umsesane, kwaye kukho mnye kuphela replicon. Xa prokaryotes ezi organelles ukuba isakhiwo ndizayo.

Ngokungafaniyo eukaryotes ezivela prokaryotes

Eyona esisiseko iiseli eukaryotic na enxulumene okufunyanisiweyo kubo izixhobo yemfuza, nto leyo ibekwe ngumongo, apho ukhuselwe iqokobhe. DNA lwabo linear ezinxulumene iiproteni histones, ezinye iiproteni zofuzo, nto leyo ndingekho iintsholongwane. Ngokuqhelekileyo, yabo umjikelo wobomi phambi zenyukliya 2 isigaba. Omnye unesethi haploid zofuzo, yaye kamva ukuhlanganisa ulwazi, 2 iiseli haploid zenze diploid, esele iquka iseti yesibini zofuzo. Kwakhona kuyenzeka ukuba kwixesha elilandelayo iseli iyahlula kwakhona uba haploid. Olu hlobo umjikelo wobomi, ngokunjalo diploidy ngokubanzi, kodwa uphawu ngenxa prokaryotes.

Umahluko umdla kakhulu kuba phambi organelles ezithile eukaryotes, okuye ezabo izixhobo zabo yemfuza nande kwiyantlukawano. Ezi zithinteli singqongwe inwebu. Ezi organelles ke mitochondria kunye plastids. Ngokutsho isakhiwo yobomi kwaye ziyafana Akumangalisi ukuba nezo iintsholongwane. Le imeko kwenza izazinzulu ukuba bacinge malunga yokuba - inzala ka eziphilayo iintsholongwane ukuba wangena ngokuncedisana eukaryotes.

Xa prokaryotes, kukho inani elincinane organelles, akukho namnye kuzo lingqongwe inwebu yesibini. Abanalo reticulum endoplasmic, izixhobo Golgi, le lysosomes.

Omnye umahluko ebalulekileyo 1 ukusuka eukaryotes prokaryotes - ubukho endocytosis ngumkhuba eukaryotes, kuquka phagocytosis kumaqela ezininzi. Le yokugqibela kukukwazi bamba ngokufaka inwebu sinomoya ngokuthi, ngoko nokugaya amasuntswana ezahlukeneyo esiqinileyo. Le nkqubo inikeza umsebenzi ebalulekileyo yokhuselo emzimbeni. Lubandakanywe nezenzo phagocytosis, ngenxa yezizathu yokuba iiseli zabo zibe avareji ubukhulu. eziphilayo Prokaryotic na obungako ngaphantsi, ngenxa yoko, ngexesha nasekusungulweni eukaryotes, kwabakho imfuneko ezinxulumene nonikezelo iiseli isixa esikhulu ukutya. Ngenxa yoko, amarhamncwa yokuqala ezihambisekayo wabonakala phakathi kwabo.

Uqwalaselo njengenye amanqanaba protein biosynthesis

Esi sigaba sesibini, leyo luqala emva kokuba umbhalo. Uqwalaselo iiprotheni kwenzeka kuphela eukaryotes. Le ekukhuleni i mRNA. Ukuze ube ngqo, oko ukususwa somhlaba musa Code for protein, nokulawula wokujoyina.

isiphelo

Kweli nqaku sichazwe emele processing (biology). Kwakhona wathi eli RNA udwelisa iintlobo zalo kanye ukuguqulwa post-transcriptional. Ithatyathwa iimpawu ezikhethekileyo eukaryotes kunye prokaryotes.

Okokugqibela kubalulekile ukuba bakhumbuze ukuba inkqubo - lo ukuyilwa RNA oqolileyo ukusuka pre-RNA.