Nta ntawm nuclear qauv. Qauv thiab muaj nuj nqi ntawm lub cell nucleus

cell nucleus - nws tseem ceeb tshaj plaws organelle, lub qhov chaw cia thiab tu tub tu kiv kev tshuaj ntsuam genetic ntaub ntawv. Qhov no daim nyias nyias qauv, uas occupies 10-40% ntawm lub hlwb, nws functions yog qho tseem ceeb heev rau lub neej ntawm eukaryotes. Txawm li cas los, txawm tias tsis muaj cov kev tshuaj ntsuam genetic ntaub ntawv tseem siv tau. Ib qho piv txwv ntawm txoj kev no yog cov muaj peev xwm mus nyob kab mob hlwb. Cuaj kaum, tus yam ntxwv nta ntawm lub nucleus thiab nws cov hom phiaj tseem ceeb heev rau ib tug multicellular kab mob.

Qhov chaw ntawm lub nucleus nyob rau hauv lub cell thiab nws cov qauv

Lub keeb yog nyob sib sib zog nqus nyob rau hauv lub cytoplasm thiab nyob rau hauv ncaj qha kev sib cuag nrog cov ntxhib thiab du endoplasmic reticulum. Nws yog surrounded los ntawm ob week, sib cais los ntawm ib tug perinuclear qhov chaw. Hauv lub ntsiav matrix yog tam sim no, ib qhov nqi ntawm chromatin thiab nucleoli.

Ib txhia paub tab tib neeg lub hlwb tsis muaj nuclei, thiab lwm tus neeg ua hauj lwm nyob rau hauv kev mob loj oppression ntawm cov kev ua ub. Nyob rau hauv kev, cov qauv ntawm cov keeb (Scheme) yog muaj tuaj raws li cov nuclear kab noj hniav bounded karyotheca los ntawm hlwb muaj chromatin thiab nucleoli, tsau nyob rau hauv lub nucleoplasm nuclear matrix.

qauv karyotheca

Rau lub yooj yim ntawm cov tub ntxhais hlwb, lub tom kawg yuav tsum tau pom raws li npuas, txwv tus neeg zoo li los ntawm lwm yam npuas. Core - nws yog ib lub raj mis ntawm kev tshuaj ntsuam genetic ntaub ntawv nyob rau hauv lub cell thickness. Los ntawm nws cytoplasm nws shielded bilayer lipid membrane. Core plhaub qauv zoo xws li cov cellular membrane. Nyob rau hauv qhov tseeb, lawv txawv xwb lub npe thiab tus xov tooj ntawm khaubncaws sab nraud povtseg. Yog tsis muaj tag nrho cov no, lawv yog cov tib nyob rau hauv cov qauv thiab muaj nuj nqi.

Qauv karyotheca (nuclear membrane) ob-txheej: nws yog tsim los ntawm ob tug lipid khaubncaws sab nraud povtseg. Bilipidny karyotheca txheej txheej ncaj qha hu cov ntxhib endoplasmic reticulum hlwb. Internal karyotheca - nrog cov tub ntxhais txheem. Nruab nrab ntawm lub txheej thiab puab kariomembranoy perinuclear qhov chaw tshwm sim. Thaj, nws tau tsim vim electrostatic phenomena - repulsion plots glycerol residues.

Cov nuj nqi ntawm lub nuclear membrane yog mus tsim ib cov neeg kho tshuab barrier ntawm lub nucleus thiab cytoplasm. Lub puab tseem ceeb yog qhov chaw membrane fixation nuclear matrix - saw protein molecules uas txhawb peb-dimensional qauv. Lub ob nuclear week muaj kev tshwj xeeb pores: los ntawm lawv mus rau lub ribosomes nyob rau hauv lub cytoplasm tub txib RNA nplooj. Thaum tus heev cov tub ntxhais thickness yog ob peb nucleoli thiab chromatin.

Lub sab hauv qauv ntawm cov nucleoplasm

Nta ntawm nuclear qauv cia peb los sib piv nws nrog rau cov cell. Hauv lub nucleus yog tseem tam sim no ib tug tshwj xeeb puag ncig (nucleoplasm) xa los ntawm huab-gel, ib tug colloidal tshuaj proteins. Hauv nws muaj nucleoskeleton (matrix), uas muaj tuaj los ntawm fibrillar proteins. Lub ntsiab sib txawv muaj xwb nyob rau hauv uas lub acidic cov nqaijrog yog tam sim no tsuas yog nyob rau keeb. Thaj, xws li ib tug tshuaj tiv thaiv cov ib puag ncig yuav tsum khaws cia cov tshuaj thaj chaw ntawm nucleic acids thiab biochemical kev tig cev.

endosome

Tus qauv ntawm lub cell nucleus yuav tsis tau ua kom tiav tsis nucleoli. Txhij yog lub helical ribosomal RNA, uas yog nyob rau hauv lub ripening theem. Tom qab ntawd, los ntawm nws tau ib tug ribosome - ib tug organelle tsim nyog rau cov protein ntau synthesis. Lub nucleolus yog cais qauv muaj ob yam: fibrillar thiab globular. Lawv txawv tsuas yog electron microscopy, thiab tsis muaj lawv cov week.

Fibrillar tivthaiv yog nyob rau hauv qhov chaw ntawm lub nucleolus. Nws nruab nrab yog ib hom ntawm ribosomal RNA strand, uas yuav tsum tau sau los ntawm ribosomal subunit. Yog hais tias peb xav txog cov tub ntxhais (qauv thiab muaj nuj nqi), nws yog pom tseeb tias ib tug granular tivthaiv yuav raug muab tsim tom qab. Cov no yog cov tib maturing ribosomal subunit, uas yog nyob rau hauv lub tom qab ua sawv ntawm nws txoj kev loj hlob. Ntawm cov ribosomes yog tsim sai sai. Lawv raug muab tshem tawm los ntawm lub nucleoplasm los ntawm nuclear pores karyotheca thiab poob mus rau hauv daim nyias nyias ntawm ntxhib endoplasmic reticulum.

Chromatin thiab cov chromosomes

Qauv thiab muaj nuj nqi ntawm lub nucleus hlwb organically txuas: nws yog tam sim no tsuas yog cov lug uas yog tsim nyog rau cov cia thiab tu tub tu kiv kev tshuaj ntsuam genetic ntaub ntawv. Kuj muaj karioskelet (matrix ntxhais) uas nws muaj nuj nqi yog kom muaj cov zoo lawm organelles. Txawm li cas los, qhov tseem ceeb tivthaiv yog lub nucleus chromatin. Qhov no chromosome, ua si lub luag hauj lwm ntawm daim ntawv indexes ntawm txawv pab pawg ntawm cov noob.

Chromatin yog ib tug complex protein uas muaj cov quaternary qauv ntawm cov polypeptide ua ke mus rau ib tug nucleic acid (RNA los yog DNA). Lub plasmids chromatin kab mob kuj tam sim no. Yuav luag ib tug peb lub hlis twg ntawm tag nrho cov hnyav li chromatin histones - cov nqaijrog lub luag hauj lwm rau "ntim" kev tshuaj ntsuam genetic ntaub ntawv. Qhov no feature ntawm cov kev tshawb fawb cov biochemistry thiab biology. Tus qauv ntawm cov tub ntxhais txoj precisely vim hais tias muaj cov chromatin thiab dab nws alternates spiralization thiab uncoiling.

Lub xub ntiag ntawm histone ua rau nws ua tau rau condense thiab Nkij los txuam rau strand ntawm DNA nyob rau hauv ib tug me me qhov chaw - nyob rau hauv lub cell nucleus. Qhov no tshwm sim raws li nram no: histones tsim nucleosomes, uas yog cov chaw xws li cov hlaws dai. H2B, H3, H4 thiab H2A - cov no yog cov ntsiab histone proteins. Nucleosome tsim los ntawm plaub khub ntawm txhua tus hais histones. Yog li histone H1 yog ib tug Linker: nws yog txuas mus rau lub DNA ntawm qhov chaw ntawm nkag teb chaws e nyob rau hauv lub nucleosome. DNA ntim yog lub txiaj ntsim ntawm "winding" linear molecule 8 histone cov protein.

Tus qauv ntawm lub nucleus, uas nws lub tswvyim yog qhia saum toj no presupposes solenoidpodobnoy DNA qauv nruab rau histones. Lub thickness ntawm cov conglomerate yog hais txog 30 nm. Tus qauv yuav tsum condensed thiab ntxiv mus nyob tsawg qhov chaw thiab tsawg raug txhua yam kev puas tsuaj inevitably tshwm sim thaum lub sij hawm ntawm tes lub neej.

Cov zauv feem ntawm chromatin

Tus qauv, cov qauv thiab cov kev ua ntawm lub cell nucleus fixated rau uas txhawb dynamic dab helix thiab uncoiling ntawm chromatin. Vim hais tias muaj ob lub ntsiab fractions thereof: ntau lub helical (heterochromatin) thiab malospiralizovannaya (euchromatin). Lawv muab faib ob leeg structurally thiab feem. Nyob rau hauv heterochromatin DNA yog zoo tiv thaiv los ntawm muaj kev cuam tshuam thiab tsis tau transcribed. Euchromatin tiv thaiv cov qaug zog, tab sis noob yuav ob npaug rau protein synthesis. Feem ntau cov feem ntau qhov chaw ntawm heterochromatin thiab euchromatin yog alternated thoob plaws hauv lub tag nrho ntev ntawm lub chromosome.

chromosome

Lub cell nucleus, cov qauv thiab cov kev khiav dej num ntawm uas yog piav nyob rau hauv phau ntawv no muaj ib tug chromosome. Qhov no yog ib tug complex thiab densely packed chromatin uas yuav pom nyob rau hauv lub teeb microscopy. Txawm li cas los, qhov no yog tsuas tau yog hais tias tus swb yog nyob rau hauv lub cell nyob rau hauv kauj ruam mitotic los yog meiotic division. Ib tug ntawm cov theem yog ib tug helix ntawm chromatin tsim chromosomes. Lawv cov qauv yog yooj yim heev: chromosome muaj ib tug telomere thiab ob txhais tes. Txhua multicellular kab mob ntawm ib hom tib lub qauv ntawm cov keeb. Rooj chromosomes nws kuj zoo sib xws.

Cov kev siv ntawm cov tub ntxhais khiav dej num

Cov yam ntxwv tseem ceeb ntawm cov tub ntxhais ntawm cov qauv txuam nrog qhov kev siv ntawm ib co zog thiab cov yuav tsum tau tswj lawv. Lub keeb ua raws li cov repository ntawm caj ces, uas yog ib yam ntawm cov ntaub ntawv nrog kaw tag nrho cov amino acid sequences ntawm cov nqaijrog uas tsim nyob rau hauv lub cell. Nws txhais tau tias rau kev ua tau zoo ib tug muaj nuj nqi, lub cell yuav tsum los ua ke protein qauv yog kho nyob rau hauv lub noob.

Yuav kom cov tub ntxhais "to taub" dab tsi txog protein yuav tsum tau tsim thaum lub sij hawm, muaj ib tug system ntawm sab nraud (membrane) thiab nrog receptors. Cov ntaub ntawv rau lawv yog txhab khoom mus rau cov tub ntxhais los ntawm txoj kev molecular transmitters. Feem ntau cov feem ntau qhov no yog ua los ntawm cov adenylate cyclase mechanism. Txij li thaum lub hlwb raug cov tshuaj hormones (epinephrine, norepinephrine), thiab ib co tshuaj nrog ib tug hydrophilic qauv.

Ib tug thib ob ntaub ntawv kis tau tus mob mechanism yog internal. Nws yog peculiar rau lipophilic molecules - corticosteroids. Qhov no tshuaj bilipidnuyu penetrates rau hauv lub cell daim nyias nyias thiab yog raws kev coj kom lub nucleus, qhov twg nws ua num ua ke nrog nws receptor. Raws li ib tug tshwm sim ntawm ua kom cov qhov receptor complex nyob rau hauv lub cell daim nyias nyias (adenylate cyclase mechanism) los yog karyotheca, cov tshuaj tiv thaiv pib ua kom ib tug me noob. Nws replicates, tub txib RNA yog lub tsev nyob rau hauv lub hauv paus ntawd. Tom qab ntawd, raws li qhov tseeb tsim cov protein uas ua ib tug muaj nuj nqi.

Cov tub ntxhais ntawm multicellular kab mob

Nyob rau hauv multicellular kab mob kev tub ntxhais qauv yog tib yam li nyob rau hauv ib-celled. Txawm hais tias muaj yog ib co nuances. Firstly, multicellular implies hais tias nws tus kheej txog kev ua (lossis tshaj ntawd) yuav tsum tseem ceeb nyob rau hauv ib tug xov tooj ntawm lub hlwb. Qhov no txhais tau tias ib co noob yog mus tas li despiralizovany, thaum lwm tus neeg yog nyob rau hauv ib tug tsaug zog hauv lub xeev.

Piv txwv li, hlwb ntawm adipose cov ntaub so ntswg protein synthesis yuav mus tsaug zog, thiab yog li ntawd feem ntau ntawm cov chromatin spiralized. Thiab nyob rau hauv lub hlwb, piv txwv li, exocrine pancreatic protein biosynthetic dab mus tsis tu ncua. Vim lawv chromatin despiralizovan. Nyob rau hauv cov cheeb tsam, lub noob yog replicated ntau zaus. Nyob rau hauv no tseem ceeb qhov tseem ceeb feature: lub chromosome teeb ntawm tag nrho hlwb ntawm lub cev yog tib yam. Tsuas yog vim hais tias ntawm lub ntau yam ntawm kev khiav dej num nyob rau hauv cov ntaub so ntswg ntawm ib co ntawm lawv tawm los ntawm kev ua hauj lwm, thiab lwm yam dispiralized feem ntau lwm tus neeg.

Nuclear-free hlwb ntawm lub cev

Muaj hlwb, uas yog cov yam ntxwv nta ntawm lub noob pob kws yuav tsis muab suav hais tias vim lawv yog cov tshwm sim ntawm lawv lub neej los yog inhibit nws muaj nuj nqi, yog kiag li tau tshem ntawm nws. Qhov yooj yim piv txwv - ntshav liab. Qhov no cov ntshav, lub nucleus ntawm qhov tam sim no xwb nyob rau hauv thaum ntxov ua sawv ntawm txoj kev loj hlob, thaum tsim hemoglobin. Thaum nws muaj nuj nqis yog txaus rau cov pa hloov lwm lub tsev, lub nucleus yog muab tshem tawm los ntawm lub hlwb, nyob rau hauv thiaj li yuav pab txhawb nws kev thauj mus los tsis cuam tshuam nrog rau oxygen.

Nyob rau hauv nws cov general daim ntawv no yog erythrocyte cytoplasmic hnab uas muaj cov qe ntshav liab. Ib tug zoo xws li cov qauv no kuj cov yam ntxwv ntawm cov roj hlwb. Qauv adipocyte cell nucleus tsis tshua muaj neeg yooj yim to taub, nws decreases thiab hloov mus rau lub membrane, thiab protein synthesis dab yog maximally inhibited. Cov hlwb kuj reminiscent ntawm "lub hnab" uas muaj cov rog, tab sis, ntawm chav kawm, ib tug ntau yam ntawm biochemical kev tig cev yog me ntsis loj tshaj ntshav liab. Platelets kuj muaj tsis muaj keeb, tab sis lawv yuav tsum tsis txhob ntshai li full-fledged hlwb. Qhov no cell tawg tsam tsim nyog rau qhov kev siv ntawm cov hemostasis txheej txheem.