Uphi kwemiqondo rRNA. RRNA Ribosomal RNA: kwebalingisi nencazelo isakhiwo

Isayensi yamangqamuzana ezinto eziphilayo iye ukutadisha isakhiwo kanye umsebenzi amangqamuzana angokwemvelo ezakha zamangqamuzana aphilayo ayizinhlobo izitshalo, izilwane kanye nabantu. Okuphawulekayo phakathi kwabo kunikezwa iqembu compounds ngokuthi nucleic (senuzi) acid.

Kunezinhlobo ezimbili: deoxyribonucleic acid (DNA) kanye ribonucleic. Lesi sakamuva has ukulungiswa eziningana: mRNA, tRNA futhi rRNA, okuyinto zingafani umsebenzi wabo futhi esikhundleni kwasendaweni kuseli. Lesi sihloko Sizokwenza ekutadisheni imibuzo elandelayo: iphi kwemiqondo rRNA e prokaryotic futhi amaseli eukaryotic, yini isimo sawo futhi incazelo.

Imininingwane zomlando

Lapho kukhulunywa ngaye okokuqala yesayensi ribosomal acid ingatholakala izifundo by R. Weinberg futhi S. umlobi ku-yalolucwaningo 60 XX leminyaka, owachaza emfushane polynucleotide-molecule ezihlobene RNA, kodwa ehlukene ngekwendzawo isakhiwo kanye sedimentation Coefficient Imininingwane nokudluliselwa RNA. Ngokuvamile, ama-molecule awo atholakala indlela yokwakheka nucleolus, futhi iseli organelles - ribosomes, obhekene synthesis amaprotheni yeselula. Babizwa ngokuthi bangabantu ribosomal (Ribosomal RNA).

Kwebalingisi RNA

Ribonucleic acid, ne-DNA, kuyinto polymer okuyiqembu monomers kukhona ama-nucleotide 4 izinhlobo: i-adenine, i-guanine uracil futhi cytidine exhunywe phosphodiester izibopho e-molecule elilodwa-balahleke eside, uwenze ube Kuvunguza kokuba yinkimbinkimbi noma conformation. Kukhona futhi kabili balahleke Ribosomal RNA okwenzeka RNA amagciwane okubili imisebenzi DNA: nokugcina kanye ne-transmission zezici sitholwa njengefa.

Kunezinhlobo ezintathu acid ezitholakala iseli avame kuba: matrix, noma ulwazi, i-RNA ezokuthutha Ribosomal RNA, lapho inamathelisiwe amino acid, kanye ribosomal acid, ise nucleolus kanye cytoplasm esitokisini.

RNA Ribosomal cishe 80% of acid ribonucleic esitokisini 60% isisindo ribosome - organelle, yeselula amaprotheni zamagama. Zonke lezi zinhlobo ezingenhla kwemiqondo (eloba) ezindaweni ezithile DNA, lezi izakhi zofuzo RNA. Phakathi kwezici engqamuzaneni abathintekayo enzyme akhethekile - RNA polymerase. Indawo esitokisini, lapho rRNA is kwemiqondo - iyona nucleolus, okuyinto umnyombo karyoplasm.

Nucleolus, yendima yayo ekuqhubeleni synthesis

Emangqamuzaneni aphilayo ngokuthi cell umjikelezo ukuhlukanisa phakathi nezigaba zawo - interphase. Ngalesi sikhathi, ngo- the kuyi-nucleus yengqamuzana emizimbeni obukhulu izakhiwo luyimbudumbudu ngokuthi nucleoli futhi iyisici esibalulekile kokubili yemifino kanye isilwane amaseli abonakala kahle.

Ngo-molecular biology, kwatholakala ukuthi nucleoli kukhona organelles lapho rRNA is kuhlelwe umqondo. Uphenyo kwaholela izingxenye ukutholakala Cytology DNA yeseli lapho izakhi zofuzo banesibopho isakhiwo kanye synthesis acid ribosomal atholakele. Babizwa ngokuthi umhleli nucleolar.

umhleli nucleolus

Kufika 60-yalolucwaningo kwekhulu XX eziphilayo khona umbono ukuthi umhleli nucleolus, elise esizeni a constriction zamabanga 13, 14, 15, 21 no-22 ngazimbili wama-chromosomes, ine uhlobo endaweni eyodwa. Abacwaningi abathintekayo ekuhloleni umonakalo chromosome, ngokuthi aberrations, bathole ukuthi kwakheka igebe sikhathi chromosome endaweni ye constriction yesibili nucleoli ngasinye zayo.

Ngakho, lokhu okulandelayo kungenziwa wathi: umhleli nucleolus lunamagama eyodwa kodwa eziningana loci (izakhi zofuzo) obhekene kumiswa nucleolus. Kuwo kwemiqondo rRNA Ribosomal RNA ukwakha subunit amaprotheni-Kuhlanganisa cell organelles - ribosomes.

Uyini ribosome?

Njengoba kushiwo ngaphambili, zonke izinhlobo ezintathu eziyinhloko-RNA khona kuseli, lapho kuhlelwe ezindaweni ezithile - izakhi zofuzo-DNA. I kwaphumela ribosomal RNA ifomu umbhalo izakhiwo kanye amaprotheni - RNPs zazo iyingxenye ye organelles esizayo, okuthiwa subunits. Ngokusebenzisa ikhule ezimbotsheni e ulwelwesi zenuzi phakathi cytoplasm they nyakazo bese bakha isakhiwo united therein ezakha i-molecule futhi namanje-RNA kanye t-RNA, ngokuthi polysomes.

Ribosome zingasuswa ahlukaniswe isenzo-calcium ion futhi sikhona ngesimo subunits ehlukile. Ukuhlanekezela inqubo efanayo kwenzeka linezingxenye we cytoplasm cell lapho izinqubo translation zenzeka - ukuhlangana molecule amaprotheni yeselula. Iseli evuliwe okukhulu kunakuqala egeleza umzimba therein kulapho liqukethe ribosomes. Ngokwesibonelo, umnkantsha amaseli, hepatocytes futhi abantu yezilwane ezinomgogodla isilwane libhekene inombolo enkulu yalezi organelles ngaphakathi cytoplasm.

Kanjani izakhi zofuzo okubhalwe rRNA?

Ngokusekelwe osekushiwo, isakhiwo, izinhlobo futhi umsebenzi rRNA izakhi zofuzo zincike umhleli nucleolar. Basuke ahlelwe loci equkethe izakhi zofuzo esephepheni ngoba RNA ribosomal. O. Miller, ucwaningo e ovogenesis Newt amaseli, lo mshini ukusebenza ezimisiwe lezi zofuzo. Ngenxa yokuthi babezimisele kwemiqondo amakhophi rRNA (okuthiwa transkriptanty eyinhloko) equkethe ama-nucleotide mayelana 13h103 nokuba Coefficient sedimentation 45 S. Khona-ke, lesi sifunda Kunenkolelo inqubo yokuvuthwa ophela ifomu molecule ezintathu p-RNA sedimentation okuza ka 5.8 S, 28 S, kanye 18 S.

Lo mshini kumiswa p-RNA

Ukubuyela Miller ucwaningo lapho uphenyo zamagama RNA ribosomal futhi wabonisa ukuthi DNA ukhonza iphethini nucleolar (-matrix) kumiswa p-RNA - transkriptanta. Uphinde wathola ukuthi inani enzyme RNA polymerase molecule incike isibalo beya acid ribosomal (pre-rRNA), okuyinto akhiwa. Khona-ke lo nokuvuthwa (processing) kanye p-RNA molecule uqale ngokushesha ukuhlanganisa uxhumano nomsebenzisi kwezinga peptides, umphumela uba ribonucleoprotein - zokwakha ribosome.

Izici ribosomal acid kumaseli eukaryotic

Ukuba izimiso ezivamile futhi kwesakhiwo sonkana etindlela obusebenzayo ribosomes prokaryotic nezinto eziphilayo yenuzi kusadingeka tsitomolekulyarnye umehluko. Ukuze uthole kubo, abacwaningi cwaningo kusetshenziswe indlela ebizwa -X-ray ukuhlaziywa. Kwatholakala ukuthi ubukhulu bale ribosome eukaryotic futhi kungakho p-RNA azifaka kuwo, futhi mkhulu sedimentation Coefficient 80 S. organelle, ukulahlekelwa magnesium ion, kungenziwa leyabantu subunits ezimbili izinkomba 60 S-40 S. kuyizinhlayiyana Small zihlanganisa omunye molecule acid ezinkulu - ezintathu, okungukuthi amaseli nucleated aqukethe ribosomes, ehlanganisa 4 polynucleotide helices acid elandelayo izici: 28 s RNA - ayizinkulungwane 5 ama-nucleotide, 18 s - ayizinkulungwane 2 5 s - nucleotide 120, 5, .. 8 S - 160. Le ngxenye lapho rRNA is kuhlelwe amaseli eukaryotic - a disintegrations nucleolus kwamanga karyoplasm-nucleus.

Ribosomal RNA prokaryotes

Ngokungafani p-RNA ngaphakathi amaseli nucleated, webhaktheriya ribosomal acid ribonucleic alotshwa engxenyeni onomfutho of cytoplasm equkethe DNA wabiza nucleoid. Liqukethe rRNA zofuzo. Ukuhlelwa, isici jikelele okungase emelelwa ulwazi ubhalwe kabusha inqubo nge p-RNA zofuzo ukulandelana DNA ribosomal ribonucleic acid nucleotide complementarity nemithetho isimiso sezakhi zofuzo: nukleoitid adenine ihambisane okuhambelana uracil, futhi i-guanine ne - cytosine.

R-RNA amagciwane abe nesisindo esiphansi ezinto Ubukhulu ezincane kuno amaseli nucleated. sedimentation yabo Coefficient S 70, kanye subunits amabili abe izinkomba 50 S futhi 30 S. I kuyizinhlayiyana ezincane iqukethe okukodwa molecule p-RNAs, futhi ezinkulu - amabili.

Indima ribonucleic acid ngesikhathi translation

Umsebenzi oyinhloko rRNA ukuhlinzeka inqubo biosynthesis weseli amaprotheni - LIVE. Kuyinto kuphela khona ribosomes equkethe rRNA. Joyina ndawonye emaqenjini, babopha ukuba molecule ye-DNA ukwaziswa obumba inqubomgomo. Ukuze-ke kusukela le cytoplasm lamaseli yezokuthutha i-molecule ribosomal acid ribonucleic efanelekayo nithela amino acid, okuyinto, kanye polysomes ahlanganiswa ndawonye yi-peptide izibopho ukwakha polymer - amaprotheni. He is ezibaluleke kakhulu organic kwakwakhe amaseli imisebenzi eminingi ebalulekile: ukwakhiwa, ezokuthutha, amandla, enzyme, ukuphepha kanye mkhosi.

Lesi sihloko bahlola isakhiwo alandisa incazelo ribosomal acid nucleic kukhona organic biopolymers amaseli phakathi kwezitshalo, izilwane kanye nabantu.