Muaj nuj nqi ntawm chromosomes thiab lawv cov qauv. Li cas rau cov chromosomes nyob rau hauv lub cell?

Qhov tsab xov xwm yuav nyob rau cov qauv ntawm eukaryotic hlwb, chromosomes, qauv thiab muaj nuj nqi yog kawm txog biology kev lag luam, hu ua cytology.

Keeb kwm ntawm foundations

Yog ib tug loj feem ntawm cov cell nucleus, chromosome nyob sab nyob rau hauv lub xyoo pua puv 19 los ntawm ob peb soj ntsuam. Ib tug Lavxias teb sab biologist I. Chistyakov kawm lawv thaum lub sij hawm mitosis (cell division), German anatomist Heinrich Wilhelm Gottfried von Waldeyer-Hartz nrhiav tau lawv thaum lub sij hawm qhov kev npaj ntawm histological npaj thiab hu ua chromosomes, uas yog uas tseg tau calves rau ceev teb ntawm cov lug nyob rau hauv lub sis raug zoo nrog organic zas xim magenta.

Fleming sau ua ke rau hauv lub pov thawj scientific rau dab tsi muaj nuj nqi yog ua los ntawm cov chromosomes nyob rau hauv lub hlwb uas tau dai kom zoo nkauj lub nucleus.

Sab nraud cov qauv ntawm chromosomes

Cov me tsim nyob rau hauv lub nuclei - qhov tseem ceeb tshaj organelles hlwb thiab ua hauj lwm raws li ib tug qhov chaw ntawm cia thiab kis tau tus mob ntawm roj ntsha cov ntaub ntawv ntawm ib tug kab mob. Chromosomes muaj ib tug tshwj xeeb muaj - chromatin. Nws yog ib tug conglomeration zoo filaments - fibrils thiab granules. Los ntawm ib tug tshuaj standpoint, qhov no compound ntawm linear DNA molecules (hais txog 40%) muaj tej histone proteins.

Ceg uas muaj xws li cov 8 peptides thiab DNA molecules Xov Paj cov ntawm protein globules, raws li coils hu ua nucleosomes. Zajlus deoxyribonucleic acid muab 1.75 revolutions nyob ib ncig ntawm tus ncej feem thiab muaj hauv daim ntawv ntawm ib tug ellipsoid txog 10 nanometers nyob rau hauv ntev thiab 5-6 nyob rau hauv dav. Lub xub ntiag ntawm cov lug (chromosomes) nyob rau hauv cov tub ntxhais ua hauj lwm pab raws li ib tug taxonomic feature eukaryotic hlwb. Nws yog nyob rau hauv daim ntawv ntawm cov nucleosomes chromosomes ua raws li cov preservation thiab kis tau tus mob ntawm kev tshuaj ntsuam genetic sijhawm.

Lub dependence ntawm cov qauv ntawm cov chromosomes ntawm lub cell voj voog theem

Yog hais tias lub cell yog nyob rau hauv interphase, uas yog yus muaj los ntawm nws khaus txoj kev loj hlob thiab cov metabolism hauv, tab sis cov tsis muaj kev sib cais, lub chromosomes nyob rau hauv lub nucleus muaj rau hauv daim ntawv ntawm nyias filaments despiralizovannyh - chromonemata. Feem ntau lawv yog intertwined, thiab visually faib lawv mus rau hauv nyias muaj nyias ib cov lug tsis yooj yim sua. Thaum lub sij hawm ntawm qhov pib ntawm cell division, uas yog nyob rau hauv Somatic hlwb yog hu ua mitosis, thiab muaj kev sib deev - meiosis, chromosomes pib helical thiab nkoog, ua ntau pom nyob rau hauv lub tshuab kuaj kab.

Theem ntawm lub koom haum ntawm chromosomes

Chav nyob ntawm caj - chromosome, tshuaj xyuas nyob rau hauv kom meej lub science noob caj noob ces. Zaum tau pom tias nucleosomal xov muaj DNA-histone cov nqaijrog tsim ib tug kauv thawj kev txiav txim. Cov tuab packing ntawm chromatin qauv tshwm sim vim tus tsim ntawm kev ua - solenoid. Nws npaaj thiab kaw nyob rau hauv ib tug txawm ntau coiled-kauj. Tag nrho cov saum toj no cov koom haum chromosome ntau ntau nyob rau hauv kev npaj rau lub hlwb los faib.

Nws yog nyob rau hauv lub mitotic voj voog ntxwv chav tsev ntawm caj, muaj raws ntawm cov noob uas muaj DNA yog zog thiab nyeem tas piv nrog filiform chromonemata interphase lub sij hawm ntawm hais txog 19 txhiab. Sij hawm. Qhov no compact daim ntawv chromosome ntsiav zog uas yog mus rau cov hloov kev tshuaj ntsuam genetic yam ntxwv ntawm tus kab mob, yog npaj rau cov faib Somatic los yog kab hlwb.

Cov morphology ntawm lub chromosomes

chromosomes muaj nuj nqi yuav tau piav los ntawm kev kawm lawv morphological nta uas zoo tshaj plaws twb tsis siv nyob rau hauv lub mitotic voj voog. Nws yog muaj pov thawj hais tias nyob rau hauv cov khoom cua theem ntawm interphase loj ntawm DNA nyob rau hauv lub cell yog ob npaug vim hais tias txhua tus ntxhais cell tsim los mus faib, yuav tsum tau tus nqi qub kev tshuaj ntsuam genetic ntaub ntawv raws li cov thawj leej niam leej txiv. Qhov no yog tiav los ntawm replication txheej txheem - tus kheej-doubling DNA muab tau los ntawm cov enzyme DNA polymerase.

Nyob rau hauv cytological npaj npaj rau lub caij ntawm lub metaphase ntawm mitosis nyob rau hauv nroj tsuag los yog tsiaj hlwb nyob rau hauv ib tug tshuab kuaj kab mob kom meej meej tias txhua chromosome yog muaj li ntawm ob qhov chaw, hu ua chromatids. Nyob rau hauv lub tom ntej theem ntawm mitosis - anaphase thiab tshwj xeeb tshaj yog telophase - lawv tag nrho sib cais tshwm sim, uas txhua chromatid ua ib tug nyias muaj nyias ib chromosome. Nws comprises tsis tu ncua compacted DNA molecule, raws li zoo raws li lipids, acid cov nqaijrog thiab RNA. Mineral tshuaj nws muaj magnesium thiab calcium ions.

Cov yuav txhawb tau cov yam ntxwv hais chromosome

Yuav kom chromosome muaj nuj nqi nyob rau hauv lub cell tau nqa tawm nyob rau hauv tag nrho, cov chav nyob ntawm caj yog ib tug tshwj xeeb ntaus ntawv - cov thawj constriction (centromere), uas yeej tsis spiralizuetsya. Hais tias nws cais lub chromosome rau hauv ob qhov chaw, hu ua lub lub xub pwg nyom. Nyob rau qhov chaw ntawm lub centromere, chromosome noob caj noob ces txwv kom muab zais ntawm sib npaug zos lub (metatsentrichnye) neravnoplechie (submetacentic) thiab akrotsentrichnye. Nyob rau hauv kev kawm ntawv tshwj xeeb thawj constrictions yog tsim - kinetochores, uas yog disk zoo li protein globules nyob rau ntawm ob sab ntawm lub centromere. Sami kinetochores muaj ob qhov chaw: sab nraud sib cuag nrog microfilaments (threaded ntxaiv) txuas mus rau lawv.

Los ntawm kev txo lub filaments (microfilaments) yog nruj me ntsis kom faib chromatids muaj lub chromosome ntawm tus ntxhais lub hlwb. Ib txhia chromosomes muaj ib los yog ntau tshaj theem nrab constrictions, uas yog tsis muab kev koom tes nyob rau hauv mitosis, vim tej no tej zaum yuav tsis koom nrog lub xov ntxaiv, tab sis cov chaw (theem nrab constrictions) muab kev tswj ntawm lub synthesis ntawm nucleoli - organelles uas yog lub luag hauj lwm rau cov tsim ntawm ribosomes.

Yuav ua li cas yog ib tug karyotype

Paub geneticists Morgan, N. Koltsov, Sutton nyob rau hauv thaum ntxov xyoo pua 20th, meticulously kawm chromosome qauv thiab muaj nuj nqi nyob rau hauv Somatic thiab kab hlwb - gametes. Lawv nrhiav tau hais tias txhua txhua cell ntawm tag nrho cov hom ntse ntawm ib tug tej tus nqi ntawm chromosomes muaj ib txog kev zoo thiab loj. Nws twb pom tias cov totality ntawm chromosomes nyob rau hauv lub nucleus ntawm Somatic hlwb hu ua karyotype.

Nyob rau hauv nrov ntaub ntawv karyotype yog feem ntau equated nrog lub chromosome teeb. Nyob rau hauv qhov tseeb, nws tsis yog zoo tib yam tswv yim. E.g., tib neeg karyotype yog 46 chromosomes nyob rau hauv lub nuclei ntawm Somatic hlwb thiab tso cai los ntawm kev noj cov mis 2n. Tab sis xws li hlwb, xws li hepatocytes (mob hlwb) muaj ob peb nuclei, lawv chromosomal complement denoted li 2n * 2 = 4n los yog 2n * 4 = 8n. Hais tias yog, tus naj npawb ntawm cov chromosomes nyob rau hauv cov hlwb yuav tsum tau ntau tshaj 46, txawm tias cov karyotype ntawm hepatocytes yog 2n, ces muaj 46 chromosomes.

Cov nab npawb ntawm cov chromosomes nyob rau hauv kab hlwb yeej ib txwm ob lub sij hawm tsawg tshaj li nyob rau hauv Somatic (nyob rau hauv lub hlwb ntawm lub cev), qhov no set yog hu ua haploid thiab yog raug xa mus rau raws li n. Tag nrho lwm cov hlwb nyob rau hauv lub cev muaj ib tug txheej ntawm 2n, hu ua diploid.

Morgan lub chromosome kev tshawb xav ntawm qub txeeg qub teg

American geneticist Morgan sab kev cai lij choj ntawm txuas qub txeeg qub teg ntawm noob, kev thwmsim rau lub hybridization ntawm txiv hmab txiv ntoo yoov, txiv hmab txiv ntoo yoov. Los ntawm nws kev tshawb fawb, cov kev ua ntawm kev sib deev chromosomes ntawm hlwb twb kawm. Morgan muaj pov thawj hais tias cov noob nyob rau hauv nyob sib ze loci ntawm tib chromosome, feem ntau pub ua ke, i.e. lub clutch. Yog hais tias lub noob yog nyob rau ntawm chromosome deb ntawm txhua lwm yam, nyob nruab nrab ntawm tus muam chromosomes tau hla dhau - sib koom chaw.

Ua tsaug rau cov kev tshawb fawb ntawm Morgan, tau tsim tshuaj ntsuam genetic maps, los ntawm cov uas kawm cov kev ua ntawm chromosomes thiab lawv uas nws kim heev nyob rau hauv kev siv genetic tswv yim mus rau qhov chaw tej teeb meem uas tau pathologies ntawm chromosomes los yog noob yuav ua tau raws roj ntsha los cov kab mob nyob rau hauv tib neeg. Qhov tseem ceeb ntawm cov lus ntawm zaum, nws yog ib qhov nyuaj rau overestimate.

Nyob rau hauv no tsab xov xwm, peb tau kawm cov qauv thiab cov kev ua ntawm chromosomes, uas lawv ua nyob rau hauv lub cell.