Baphi-chromosomes? Libanga 6 ke kweqiwe? Kodwa ungakhathazeki, sizoyithola impendulo yalo mbuzo, kanye ukunquma ukuthi kubaluleke kangakanani ukuba izinto eziphilayo. Iyini indlela yokuhlala kanye nokwakha?
A akanhlanhlatsi encane
Ngokuvamile ama-chromosome ziyingxenye ebalulekile ye mshini isakhi sofuzo. Ikhonza njengabameleli indawo ekhiqiza DNA. Amanye amagciwane abe ingqamuzana elilodwa-balahleke, kodwa ezimweni eziningi dvutsepochnye futhi komugqa noma uvaliwe iringi. Kodwa-DNA kuma-chromosome elise ngokukhethekile eziphilayo yeselula. Okungukuthi, lokhu isitoreji amagciwane alisetshenziswa umqondo evamile, njengoba lesi silwanyana ngokwayo ukhonza nalesi sabelo. Lapho ama-molecule ekunqandeni endaweni Kuvunguza ahlelwe emfishane. Ngokuvamile ama-chromosome yakhiwa chromatin. Lokhu fibre ekhethekile aba khona uma uphonsa DNA eukaryotic wind amaprotheni izinhlayiya ekhethekile okuthiwa histones okuyinto. Basuke etholakala ngemva kweminyaka ethile, ngakho isakhiwo esitebeleni eyatholakala.
mayelana Ama-chromosomes e
Bangabaholi main kwesakhiwo izakhi yeseli-nucleus. Ngenxa yokuba khona self-ukukhiqizwa kabusha ikhono, ama-chromosome ungahlinzekela isixhumanisi zofuzo phakathi izizukulwane. Kufanele kuqashelwe umehluko yabo obuphelele e ezahlukene izilwane nabantu: zabo usayizi ziyahlukahluka kusuka enamafrakshini ukuze amashumi microns. Njengoba elisekela amakhemikhali ukwakhiwa esetshenziswa nucleoproteins ukuthi akhiwa namaprotheni anjenge protamines futhi histones. Ngokuvamile ama-chromosome kukhona njalo ku le kuyi-nucleus yengqamuzana. Futhi lokho kusebenza kuwo wonke amafomu kungenzeka eliphakeme lempilo. Ngakho, isitatimende waphonsa mayelana ukuphi chromosome kumaseli isilwane, ne ncamashi ngendlela efanayo akunakubangelwa izitshalo. Bheka ngefasitela. Yimiphi imithi Ungase umbone? Linden, oki, birch, ziyadliwa? Noma mhlawumbe ezihlabayo currant kanye raspberries? Ebuzwa ukuthi ukuphi lezakhi zofuzo izitshalo eziye esohlwini, singasho ukuthi basuke endaweni eyodwa futhi izilwane - e le nuclei amaseli.
Indawo-chromosomes e-cell: kanjani ukuba wenze isinqumo
eukaryotes ezinamangqamuzana amaningi ungumnikazi inombolo diploid lezakhi zofuzo. Yenziwe ufuzo ka ubaba nomama. Ngokusebenzisa inqubo meiosis basuke conjugated ndawonye. Linikeza ukugeleza-amasayithi okwabelana - crossover. Okungenzeka kulezi amacala ukubhanqa wama-chromosomes homologous. Lokhu kuyadingeka ukuqinisekisa ukusebenza zezakhi zofuzo kumaseli ukuthi musa ezihlukanisa, futhi kukhona esimweni ukuphumula. Okungenxa lokhu is phetho ukuthi chromosome atholakala kuyi-nucleus, futhi ukuqhubeka nemisebenzi ukwahlukana abanayo ukushiya ngaphandle. Yiqiniso, ukuthola izinsalela nucleotide kuseli ngokwayo akunzima. Kodwa ezimweni eziningi, noma ufuzo ku mitochondria, noma izingxenye ngazinye iyonke, ephukile futhi manje "ezintantayo khulula". Hlangana ne-chromosome ngokugcwele ngaphandle nucleus kunzima kakhulu. Futhi uma lokho kwenzeka, kuba kuphela ngenxa umonakalo ngokomzimba.
chromosome isethi
Ngakho sikubiza isiqalo nesigcino wama-chromosomes, okuyizinto kuyi-nucleus yengqamuzana. Ngamunye zilwane ayo alandisa unomphela simiselwe kuye, okuyinto zase zihleliwe phakathi kwemvelo. Kungaba ezinhlobo ezimbili: elilodwa (noma haploid, itholakala igciwane amaseli kwezilwane) futhi double (noma diploid). Imisa inombolo ehlukile wama-chromosomes okukhona. Ngakho, inani amahhashi zilingane ezimbili. Kodwa ngo izitshalo elula futhi ezithile spore eziveza, inombolo yabo ongafinyelela izinkulungwane. By endleleni, uma sikhuluma lapho chromosome atholakala bacterium, kufanele kuphawulwe ukuthi nazo, njengoba umthetho, zitholakala nucleus, kodwa kungenzeka nokuthi zingabantu "khulula" ukuntanta le cytoplasm. Kodwa lokhu kwenzeka kuphela kubantu owumphumela. Futhi azigcini nje ngokuhluka inombolo kodwa futhi ubukhulu. Kubantu, kukhona iqoqo Ama-chromosomes e-46.
I morphology we-chromosomes
It is kuhlobane ngokuqondile Helix yabo. Ngakho, lapho interphase isinyathelo, basuke enwetshiwe kakhulu. Kodwa ekuqaleni inqubo yokuhlukanisa chromosome baqale ngokushesha mfushane kokuqhuba Helix yayo. Izinga eliphezulu kakhulu ngalesi simo ewela metaphase esiteji. It kwakhiwa isakhiwo esifushane futhi obukhulu. kwakhiwa Metaphase chromosome is kusukela chromatids ezimbili. Lezi babuye sakhiwa okuthiwa lokuluhlaza aphansi (chromonemata).
Ama-chromosomes e ngabanye
Bona iyashiyana kusayithi indawo centromere (constriction okuyinhloko). Uma le ngxenye elahlekile ke chromosome bangalahlekelwa ukukwazi kwabo ukwehlukana. Futhi constriction eyinhloko uhlukanisa chromosome emahlombe ezimbili. Ingase futhi yakha yesibili (kulesi simo umphumela ibizwa ngokuthi satellite). Uhlobo ngalunye has eziphilayo ethize zalo (anda, by ezindlini ezingakanani noma ezime) amasethi chromosome. Uma kuba kabili, libizwa ngokuthi i-karyotype.
I chromosomal imfundiso yokuziphendukela ufuzo
Ngokokuqala ngqá, lezi zimoto iye yachazwa ID Chistyakov e 1874. Ngo-1901 Wilson yabhekisela khona impindamqondo ekuziphatheni kwazo. Khona-ke wagxila Mendeleev ufuzo zici meiosis kanye kokukhulelwa, futhi wafinyelela esiphethweni ekutheni izakhi zofuzo zitholakala kuma-chromosome. Kuyo yonke le minyaka 1915-1920 ngu Morgan futhi udondolo lwakhe kulesi sikhundla okuye kungase kutholakale. Bona okwasekhaya abangamakhulu amaningana izakhi zofuzo kuma-chromosome ka Drosophila, ukudala ibalazwe lokuqala zofuzo. Idatha etholwe ngalesi sikhathi kwakheka isisekelo sokuthuthukiswa okwalandela isayensi kulesi siqondiso. Futhi ngesisekelo lolu lwazi yasungulwa theory chromosomal ufuzo lapho amaseli bese eziphilayo wonke embili kuqinisekiswa sibonga lezi abezindaba.
amakhemikhali ukwakheka
Ucwaningo baqhubeka, futhi phakathi ucwaningo kwamakhemikhali kanye cytochemical eminyakeni 30-50 of leminyaka elidlule, kwatholakala ukuthi basuke ahlelwe. Ukwakheka wabo ngendlela elandelayo:
- Basic amaprotheni (histones futhi protamines).
- DNA.
- Negistonnye amaprotheni.
- izingxenye eliguqukayo. Zingase ukwenza njenge amaprotheni esidi RNA.
Ngokuvamile ama-chromosome akhiwa ka sesigcilikisha dezoksiribonukleoproteidnyh. Abakwazi uxhumeke imishayo. Ngo-1953, isakhiwo kwatholakala DNA nokuhlaziwa mshini autoreproduction yayo. I lwati lolutfolakele ikhodi nuclein wakhonza njengoba isisekelo ukuvela kwesayensi entsha - zofuzo. Manje thina nje kuphela ukwazi ukuthi yengqamuzana-chromosome, kodwa futhi unombono lokho zenziwa. Lapho ingxoxo evamile kwansuku ukhuluma ngani apharathasi ngofuzo, ngokuvamile kusho omunye DNA, kodwa wena ube wazi okuthile manje ukuthi kumane nje kuyingxenye yomthwalo yakhe.
Ama-chromosomes e ucansi
Amangqamuzana okuyinto banesibopho kwesigamu isilwane (futhi abantu ikakhulukazi), kukhona pair ekhethekile. Kungenzeka kukhona ezinye izimo lenhlangano lapho konke inqunywa ratio uhlobo wama-chromosomes ubulili ngayinye. Izilwane ezinalokhu uhlobo oluthile enjalo, ebizwa ngokuthi autosomes. Kubantu, okufanayo (, elezinye izilwane ezincelisayo kuhlanganise) wobulili besifazane kunqunywa Ama-chromosomes e efanayo, okuyinto zibizwa ngokuthi X. Ukuze owesilisa isebenzisa X Y. Kodwa lokho ukhetha ukuthi ubulili umntwana? Ekuqaleni ovuthiwe yenethiwekhi zesifazane (amaqanda), okuyinto yokuhlala H. A phansi njalo kunqunywa okuqukethwe spermatocytes. Ziyakwazi ngezabelo alinganayo (plus / lokususa) aqukethe kokubili X Y chromosome. Kusuka kwabezindaba, okuzokwenza lo kokukhulelwa lokuqala, futhi kuncike ucansi ingane. Ngenxa yalokho, kungenzeka noma owesifazane (XX) noma owesilisa (XY). Ngakho, asigcinanga batholakala lapho kulandiswa khona-chromosome kubantu kukhona, kodwa futhi asebenzelana ngayo izici ukubekwa yabo futhi inhlanganisela ukwakha umzimba omusha. Kumele kuqashelwe ukuthi le nqubo kancane lokukhululwa amafomu lula zokuphila, ngakho-ke, ukwazi ukuthi yini oyithandayo bese kwemali, ungase uqaphele umehluko othize kusukela elichazwe lapha imodeli.
ukusebenza
Chromosomal DNA kungenziwa imelelwa matrix, nesebenzela synthesize ethize isithunywa RNA molecule. Nokho, le nqubo ingathatha indawo kuphela uma othile despiralization ingxenye. Ukukhuluma mayelana nokwenzeka ukusebenza isakhi noma ukufakela ama-chromosome lonke, kufanele kuphawulwe ukuthi izimo ezithile ezidingekayo ukuze ukusebenza kwabo. Mhlawumbe usuke wezwa insulini? Isakhi sofuzo esiyimbangela yalesi ukukhiqizwa yayo, ine wonke umzimba womuntu. Kodwa lokho sika isebenze futhi ikani umsebenzi kuphela uma ngakwesokudla amaseli Dala kwamanyikwe. Futhi Ezimweni ezinjalo eziningi. Uma sikhuluma baxoshwe umzimba chromosome wonke, khona-ke kungenzeka ukuba sikhumbule ukwakheka komzimba ubulili chromatin.
Ama-chromosomes e womuntu
Ngo-1922 Peytnerom iye hypothesized ukuthi umuntu inama-chromosome angu-48. Yiqiniso, kwakungadingeki uthe aphume ndawo, futhi isekelwe idatha ethile. Kodwa ngo-1956, ososayensi iThire Levan usebenzisa izindlela zakamuva zocwaningo okusha ngezakhi zofuzo zomuntu, kwatholakala ukuthi eqinisweni umuntu inama-chromosome angu-46 kuphela. Basuke futhi unikezwa incazelo karyotype yethu. Njengoba babengaphezu umusi isuka omunye amabili nantathu. Nakuba umbhangqwana ekugcineni yikona okuvame hhayi inikezwa inamba, futhi eceleni ngokuthi, lokho kwenziwa.
isiphetho
Ngakho, siye esichaziwe isihloko, yini indima babe le-chromosome ukuthi zikuphi futhi indlela yokwakha. Yiqiniso, i-main kwagxilwa okusha ngezakhi zofuzo zomuntu, kodwa zibuyekezwe izilwane kanye nezitshalo futhi. Siyazi lapho kuseli kukhona chromosome, ikakhulukazi indawo yabo, kanye kugucuka kungenzeka ukuthi kungenzeka nabo. Uma sikhuluma ufuzo ke khumbula ukuthi kungaba kwezinye izingxenye, hhayi nje nengaphakathi. Kodwa nansi Eqinisweni, yiziphi ingane letigcogcwe ngaphambilini, umphumela kuba ukuthi kukhona kuma-chromosome. Futhi isibalo add akuxhomekile kakhulu izici umzimba. Ngakho, niyikhulume lapho chromosome kuseli yezitshalo nezilwane eziphilayo, siyakholwa ukuthi umsebenzi wethu, yaqedwa ukwakhiwa.