Qhov twg yog tsim rRNA. RRNA Ribosomal RNA: characterization thiab cov hauj lwm ntawm cov qauv

Molecular biology uas tau raug kawm cov qauv thiab cov kev ua ntawm cov organic molecules uas ua tau nyob hlwb ntawm cov nroj tsuag, tsiaj txhu thiab tib neeg. Notable ntawm lawv yog muab ib tug pab pawg neeg ntawm tebchaw hu ua nucleic (nuclear) acids.

Nws muaj ob hom: deoxyribonucleic acid (DNA) thiab ribonucleic. Cov yav tas muaj ob peb hloov: mRNA, tRNA thiab rRNA, uas txawv nyob rau hauv lawv muaj nuj nqi thiab qhov chaw ntawm localization nyob rau hauv lub cell. Qhov tsab xov xwm yog mob siab rau txoj kev tshawb no ntawm cov hauv qab no cov lus nug: qhov twg yog tsim rRNA nyob rau hauv prokaryotic thiab eukaryotic hlwb, dab tsi yog nws cov qauv thiab cov ntsiab lus.

keeb kwm ntaub ntawv

Tus thawj scientific mention ntawm ribosomal acid yuav muaj nyob rau hauv cov kev tshawb fawb los ntawm R. Weinberg thiab S. Penman nyob rau hauv lub 60-ies ntawm XX xyoo pua, leej twg piav ib tug luv luv polynucleotide molecule txog rau RNA, tab sis txawv spatial qauv thiab sedimentation coefficient ntawm cov ntaub ntawv thiab hloov RNA. Feem ntau cov feem ntau, lawv molecules yog pom nyob rau hauv nyob tus yeees ntawm cov nucleolus, thiab cell organelles - ribosomes, lub luag hauj lwm rau lub synthesis ntawm cellular protein. Lawv hu ua ribosomal (Ribosomal RNA).

Characterization ntawm RNA

Ribonucleic acid, zoo li DNA, yog ib tug polymer ntawm uas tus monomers yog nucleotides 4 hom: adenine, guanine, uracil thiab cytidine kev cob cog rua phosphodiester bonds nyob rau hauv ntev ib leeg-tso tseg molecules, cov mus rau hauv ib tug kauv muaj ib tug ntau los yog zoo. Muaj kuj muab ob npaug rau-tso tseg Ribosomal RNA tshwm sim nyob rau hauv RNA cov kab mob thiab theej tawm DNA zog: kev tswj thiab kis tau tus mob ntawm roj ntsha sijhawm.

Peb hom kev acids pom nyob rau hauv lub cell feem ntau yog: ib tug matrix, los yog cov lus qhia, RNA thauj Ribosomal RNA, uas yog txuas amino acids, zoo li ribosomal acid, nyob rau hauv lub nucleolus thiab lub cytoplasm ntawm lub cell.

Ribosomal RNA yog kwv yees li 80% ntawm cov ribonucleic acids nyob rau hauv lub cell thiab 60% ntawm qhov loj ntawm lub ribosome - organelle, cellular protein synthesis. Tag nrho cov saum toj no hom muaj tsim (transcribed) nyob rau hauv tej yam cov cheeb tsam ntawm DNA, cov RNA noob. Thaum lub sij hawm lub synthesis ntawm cov molecule muab kev koom tes tshwj xeeb enzyme - RNA polymerase. Qhov chaw nyob rau hauv ib lub cell, qhov twg rRNA yog tsim - yog lub nucleolus, uas yog nyob rau karyoplasm tub ntxhais.

Nucleolus, nws lub luag hauj lwm nyob rau hauv lub synthesis ntawm

Nyob rau hauv nyob hlwb, hu ua cell voj voog qhov txawv nruab nrab ntawm nws kev sib cais - interphase. Thaum lub sij hawm no, nyob rau hauv lub cell nucleus tuab lub cev granular lug hu ua nucleoli thiab yog ib tug tseem ceeb ntawm ob zaub thiab tsiaj hlwb zoo pom.

Nyob rau hauv molecular biology, nws twb pom hais tias cov nucleoli yog cov organelles qhov twg rRNA yog tsim. Ntxiv tshawb coj mus rau lub foundations cytology qhov chaw ntawm lub cell DNA nyob rau hauv uas lub noob yog lub luag hauj lwm rau cov qauv thiab cov synthesis ntawm ribosomal acids tau pom. Lawv hu ua nucleolar organizer.

nucleolus organizer

Mus txog rau 60-ies ntawm lub XX xyoo pua hauv ib yog ib tug tswv yim hais tias lub nucleolus organizer, nyob rau ntawm qhov chaw ntawm ib tug thib ob constriction nyob rau hauv 13, 14, 15, 21 thiab 22 officers ntawm chromosomes, muaj hauv daim ntawv ntawm ib tug tib qhov chaw. Soj ntsuam kev koom tes nyob rau hauv txoj kev tshawb no ntawm chromosome kev puas tsuaj, hu ua aberrations, tau pom tias lub sij hawm kis chromosome ntawm qhov chaw ntawm lub qhov constriction yog tsim nucleoli ntawm txhua yam ntawm nws qhov chaw.

Yog li, cov nram qab no yuav tsum tau hais tias: nucleolus organizer muaj tsis ib tiam sis ob peb loci (noob) lub luag hauj lwm rau cov tsim ntawm nucleolus. Nws nyob rau ntawd tsim rRNA Ribosomal RNA txoj kev subunit protein-synthesizing cell organelles - ribosomes.

Yuav ua li cas yog ib tug ribosome?

Raws li hais ua ntej lawm, tag nrho peb lub ntsiab hom RNA muaj nyob rau hauv lub cell, qhov uas lawv yuav tsim nyob rau hauv tej qhov chaw - DNA noob. Cov uas ua ribosomal RNA transcription daim ntawv ceg nrog cov nqaijrog - RNPs uas ntaub ntawv ib feem ntawm yav tom ntej organelles, thiaj li hu ua subunits. Los ntawm pores nyob rau hauv lub nuclear membrane mus rau hauv lub cytoplasm, lawv tsiv mus nyob thiab tsim ib tug united qauv nyob rau ntawd, muaj cov molecule thiab tseem-RNA thiab t-RNA, hu ua polysomes.

Ribosome lawv tus kheej yuav tau muab cais los ntawm qhov kev txiav txim ntawm calcium ions thiab muaj nyob rau hauv daim ntawv ntawm cais subunits. Rov qab tib yam txheej txheem tshwm sim nyob rau hauv lub compartments ntawm lub cell cytoplasm qhov twg translation dab tshwm sim - assembling molecules cellular proteins. Lub active cell ntau sib ntws nyob rau ntawd metabolism, qhov ntau nws muaj ribosomes. Piv txwv li, hloov hlwb pob txha hlwb, hepatocytes thiab tib neeg vertebrate tsiaj yus muaj los ntawm ib tug loj tus naj npawb ntawm cov organelles nyob rau hauv lub cytoplasm.

Yuav ua li cas noob encoded rRNA?

Raws li cov foregoing, tus qauv, hom thiab muaj nuj nqi ntawm rRNA noob nyob ntawm seb lub nucleolar organizer. Lawv cov txheej txheem ntawm loci muaj noob cai rau ribosomal RNA. O. Miller, kev tshawb fawb nyob rau hauv ovogenesis Newt hlwb, lub mechanism tsim hauj lwm ntawm cov noob. Txij li thaum lawv tsim cov ntawv luam ntawm rRNA (thiaj li hu ua thawj transkriptanty) uas muaj txog 13h103 nucleotides thiab muaj ib tug sedimentation coefficient ntawm 45 S. Ces, qhov no Circuit Court yog muaj ripening txheej txheem xaus daim ntawv peb molecules ntawm p-RNA sedimentation coefficients ntawm 5.8 S, 28 S, thiab 18 S.

Lub mechanism ntawm tsim ntawm p-RNA

Rov qab mus rau Miller thwmsim uas tshawb xyuas cov synthesis ntawm ribosomal RNA thiab pom tias DNA ua hauj lwm pab nucleolar qauv (matrix) rau cov tsim ntawm p-RNA - transkriptanta. Nws kuj pom hais tias tus nqi ntawm cov enzyme RNA polymerase molecules nyob rau hauv lub xov tooj ntawm tsis paub qab hau ribosomal acids (pre-rRNA), uas yog tsim nyob rau. Ces tus maturation (ua), thiab p-RNA molecules pib tam sim ntawd khi rau cov peptides, qhov tshwm sim yog ib tug ribonucleoprotein - tsev cov ntaub ntawv uas ribosome.

Nta ribosomal acids nyob rau hauv eukaryotic hlwb

Muaj ntau cov ntsiab cai thiab zuag qhia tag nrho cov qauv ntawm cov kev haumxeeb mechanisms ntawm prokaryotic ribosomes thiab nuclear kab mob tseem muaj tsitomolekulyarnye sib txawv. Yuav kom nrhiav tau lawv, txoj kev tshawb soj ntsuam siv ib txoj kev hu ua X-ray tsom xam. Nws pom hais tias lub qhov ntau ntawm cov eukaryotic ribosome thiab chaw pib lub p-RNA muaj nyob rau hauv nws, thiab ntau dua sedimentation coefficient ntawm 80 S. organelle, poob magnesium ions, yuav tau muab cais mus rau hauv ob subunits nrog indicators, As 60 S thiab 40 S. Me particle muaj ib tug qauv ntawm acid thiab loj - peb, i.e. nucleated hlwb muaj ribosomes, muaj raws ntawm 4 polynucleotide helices acid nram qab no yam ntxwv: 28 s RNA - 5 txhiab nucleotides, 18 s - 2 txhiab 5 s - 120 nucleotides, 5, .. 8 S - 160. Cov feem qhov twg rRNA yog tsim nyob rau hauv eukaryotic hlwb - ib tug nucleolus disintegrations cuav nyob rau hauv karyoplasm nucleus.

Ribosomal RNA prokaryotes

Tsis zoo li p-RNA nyob rau hauv lub nucleated hlwb, kab mob ribosomal ribonucleic acids uas yog transcribed nyob rau compressed feem ntawm cytoplasm muaj DNA thiab hu ua nucleoid. Nws muaj lub rRNA noob. Kev kho, ib tug general yam ntxwv uas yuav tsum tau sawv cev los ntawm cov ntaub ntawv rewriting txheej txheem nrog p-RNA noob nyob rau hauv lub DNA sib lawv liag ntawm ribosomal ribonucleic acid nucleotide complementarity nrog cov kev cai ntawm lub caj code: adenine nukleoitid hnov uracil, thiab guanine - cytosine.

R-RNA kab mob muaj ib tug tsawg dua molecular nyhav thiab me me qhov ntev tshaj lub nucleated hlwb. Lawv sedimentation coefficient S 70, thiab tus ob subunits muaj ntsuas 50 S thiab 30 S. Tus me particle muaj ib tug qauv ntawm p-RNAs, thiab loj - ob.

Lub luag hauj lwm ntawm lub ribonucleic acid thaum lub sij hawm translation

Lub ntsiab muaj nuj nqi ntawm rRNA yog muab ib tug txheej txheem ntawm biosynthesis ntawm cell protein - NYOB. Nws yog xwb nyob rau hauv lub xub ntiag ntawm ribosomes muaj rRNA. Koom ua ke nyob rau hauv pab pawg, lawv khi mus rau lub DNA molecule ntawm cov ntaub ntawv txoj kev txoj cai. Yuav kom nws los ntawm lub cytoplasm ntawm hlwb haum thauj molecule ribosomal ribonucleic acids kev coj tus kheej amino acids, uas, ib zaug nyob rau hauv polysomes txuas ua ke los ntawm peptide bonds tsim tau ib cov polymer - protein. Nws yog tus tseem ceeb tshaj plaws organic compound hlwb ua ntau yam tseem ceeb functions: kev tsim kho, thauj, zog, enzyme, kev ruaj ntseg thiab signaling.

Qhov tsab xov xwm soj ntsuam tus yam ntxwv qauv thiab piav qhia txog ribosomal nucleic acids yog organic biopolymers hlwb ntawm cov nroj tsuag, tsiaj txhu thiab tib neeg.