Kangakanani ubungako bokudlulisa? ukuqoqwa Izinhlobo

Njalo cell siqala ukuphila layo lapho zihlukana umzali, futhi ugcina ngokuba, enikeza ithuba kubonakale indodakazi kangakanani ezitokisini zabo. Nature enikeziwe ezingaphezu kweyodwa sokuhlukanisa core, kuye isakhiwo sabo.

Izindlela cell division

Kwehlukanisa nengaphakathi incike uhlobo cell :

- ukuqoqwa kanambambili (atholakala prokaryotes).

- amitosis (ngqo ngendlela division).

- Mitosis (ezivamile eukaryotes).

- Meiosis (yokuhlukanisa germ cells).

ukuqoqwa izinhlobo kunqunywa imvelo futhi uhambisane isakhiwo esitokisini futhi umsebenzi ke wenza e macroorganism noma ngokwalo.

ukuqoqwa kanambambili

Ngokuvamile lolu hlobo itholakala amaseli prokaryotic. Siqukethe e kabili isiyingi DNA. ukuqoqwa Binary ka-nucleus is abizwa kanjalo ngenxa iseli umama kukhona ezimbili indodakazi ngokulinganayo obujwayelekile.

Ngemva ndaba zofuzo (DNA noma RNA-molecule) usulungisiwe ngokufanele, isb ke kabili, kusukela odongeni cell uqala ukwakha ukwahlukanisa transverse, okuyinto kancane kancane tapered futhi cytoplasm ihlukane izingxenye ezimbili zilingana.

Eyesibili inqubo kuhlukane ngokuthi Olufufusayo noma engalingani ukuqoqwa kanambambili. Kulokhu, izindonga iseli avele protrusion ingxenye, okuyinto kancane kancane ezikhulayo. Emva "nezinso 'futhi ubukhulu cell umama kuzolingana, zihlukaniswa. Ingxenye odongeni cell is kuhlelwe umqondo futhi.

amitosis

Lesi sigaba of nucleus ezifana nalezo ezichazwe ngenhla, ne umehluko ukuthi akukho kabili izinhlayiya eziyisisekelo zofuzo. Le ndlela yaqale esachazwa Remak sezinto eziphilayo. Lokhu kwenzeka ngo-amaseli pathologically okushintshiwe (ukuguqulwa abulalayo), futhi inkambiso bokuphila for izicubu isibindi, uqwanga futhi cornea.

Le nqubo ibizwa ngokuthi yenuzi ukuqoqwa amitosis ngoba cell azigcina umsebenzi walo, futhi akusho ukulahlekelwa yizo phakathi mitosis. Lokhu kuwachaza kahle izakhiwo okungavamile ezihlobene inqubo cell division. Ngaphezu kwalokho, oqondile division core sihamba ngaphandle othini lokuphotha, ngakho indodakazi amaseli chromatin isakazwa nombala. Ngo okulandelayo, amaseli anjalo Awukwazi ukusebenzisa umjikelezo mitotic. Ngezinye izikhathi, ngenxa amitosis kwakhiwa amaseli multinucleated.

mitosis

Lokhu ukuqoqwa kwemibhalo engesobala. Ngokuvamile ezitholakala amaseli eukaryotic. Umehluko omkhulu yale nqubo itholakala lokuthi ukuthi ingane namaseli komama aqukethe inani elifanayo chromosome. Ngalesi umzimba isekelwa inani elidingekayo amaseli, kanye ngangokunokwenzeka ukuvuselelwa nokukhula izinqubo. I mitosis kuqala eyeseli isilwane echazwe Flemming.

Inqubo yokuhlukanisa nucleus kulokhu ahlukaniswa ngqo ku interphase futhi mitosis. Interphase - esimweni amaseli ukuphumula phakathi ukwahlukana. Kungaba ukuhlukanisa izigaba eziningana:

1. Isikhathi presynthetic - iseli likhula, aqoqana amaprotheni kanye carbohydrate, limatasa kwemiqondo ATP (adenosine triphosphate).

2. isikhathi Zokwenziwa - izinhlayiya eziyisisekelo zofuzo ngokuphindwe kabili.

3. isikhathi postsynthetic - izakhi yeselula kuthiwa kabili, kukhona amaprotheni ezakha lokuphotha kuhlukane.

Izigaba mitosis

Ukuhlukaniswa nucleus amaseli eukaryotic - inqubo okuyilona elidingekayo ukuze umuntu ekumiseni organelles eyengeziwe - centrosomes. Itholakala eduze nucleus futhi umsebenzi wayo oyinhloko yakha organelles entsha - uthi lokuphotha. Lesi sakhiwo kuyasiza ngokulinganayo ukusabalalisa chromosome phakathi indodakazi amaseli.

Kunezinhlobo ezine izigaba mitosis:

1. Prophase: chromatin nucleus uba ku chromatids, okuyizinto eduze centromeres bayahamba ngababili ukwakha chromosome. Nucleoli chaza, ziyahlakazeka zingene izigxobo we centrioles cell. Kwakheka division uthi lokuphotha.

2. Metaphase: chromosome ahlelwe umugqa edabula maphakathi iseli esebumba ipuleti metaphase.

3. Anaphase: chromatids washintsha kusukela maphakathi cell maqondana Kuma-pole, bese lahlukaniswa centromere. Lokhu ukuhamba kungenzeka ngoba uthi lokuphotha division, imicu okuyinto ziyancipha futhi welulela-chromosomes bacondze etindzaweni letehlukene.

4. Telophase: Kumiswa indodakazi nuclei. Chromatids futhi jikisa chromatin, lakha is, laphakathi kwawo kulelitshe - the nucleoli. Iphela zonke Ukuhlukaniswa cytoplasm cell udonga kumiswa.

endomitosis

Ukwanda nesidoda okunikelwe, okuyinto engabondli abakubo Ukuhlukaniswa nucleus ngokuthi endomitosis. Sitholakala amaseli zezitshalo nezilwane. Kulokhu akukho kubhujiswa lesi cytoplasm kanye ulwelwesi nucleus, kodwa iba chromatin ku-chromosomes, bese dispiralized.

Le nqubo ivumela ukuthola nucleus polyploid lapho okuqukethwe DNA luyanda. ikoloni okunjalo ukwakha amaseli ezitholakala umnkantsha. Ngaphezu kwalokho, kukhona amacala, lapho i-molecule ye-DNA ngokuphindwe kabili, futhi inani lezakhi zofuzo ayiguquki. Baziwa njengezakhamuzi polythene, futhi ingatholakala amaseli isinambuzane.

okusho mitosis

division Mitotic ka-nucleus - kuyindlela ukulondoloza isethi njalo lezakhi zofuzo. Indodakazi amaseli abe isethi efanayo zezakhi zofuzo njengomzali futhi zonke izici esingokwemvelo kuso. Mitosis kuyadingeka ukuze:

- ukukhula nokuthuthuka eziphilayo ezinamangqamuzana amaningi (kusukela Fusion lwegciwane amaseli);

- displacement we ephansi iseli izingqimba ngesikhathi phezulu futhi esikhundleni egazi (erythrocyte, leukocyte, izinhlayiya zegazi);

- ukulungisa ezilimele izicubu (kwezinye izilwane sinekhono ukuvuselelwa kungokudingekayo okusinda, ezifana starfish nezibankwa);

- ukukhiqizwa kabusha asexual zezitshalo nezilwane ezithile (ezingenamgogodla).

meiosis

sokuhlukanisa germ cells indlela nuclei awafani nse kusukela ukuphathwa kwabathintwayo. Ngenxa yalokho, wathola amaseli abe nengxenye ulwazi zofuzo okwabahlula ababengaphambi zabo. Lokhu kuyadingeka ukuze balondoloze inombolo njalo lezakhi zofuzo engqamuzaneni ngalinye zomzimba.

Meiosis Kwenzeka ngezigaba ezimbili:

- ukuncishiswa esiteji;

- esiteji equational.

Proper phakathi kwenqubo kungenzeka kuphela amaseli nge ngisho inani lezakhi zofuzo (diploid, tetraploid, futhi geksaproidnym t. D.). Yiqiniso, luhlala kungenzeka ukuba kudlule meiosis namaseli ngesethi obungavamile Ama-chromosomes e, kodwa ke nenzalo kungase kungabi iphila.

Le ndlela yokwenza kuqinisekisa inzalo yabantu abasemishadweni edonsa interspecific. Kusukela ngo-igciwane amaseli amasethi ezahlukene wama-chromosomes, ke inkimbinkimbi Fusion yabo futhi ukubukeka inzalo iphila futhi evundile.

Lesi sigaba sokuqala meiosis

isigaba iphindwa igama labo mitosis: prophase, metaphase, anaphase, telophase. Kodwa kukhona ezinye umehluko omkhulu.

1. Prophase: isethi double wama-chromosomes kwenza uchungechunge kugucuka, edabula izigaba ezinhlanu (leptotena, zygotes, Paquita, diplotene, diakinesis). Kukhona konke lokhu sibonga conjugation futhi siwela ephezulu.

Conjugation - lokhu Kuhlangana wama-chromosomes homologous. Ngo leptotene therebetween yakha sesigcilikisha mncane bese ujoyine zygotene chromosome ngazimbili kanye yi etholwe isakhiwo chromatids ezine.

Crossover - inqubo cross-izingxenye exchange phakathi udade chromatids noma ukufakela ama-chromosome homologous. Lokhu kwenzeka ngesikhathi isigaba pachytene. ezimpambanweni Kwakheka (chiasm) kuma-chromosome. Kubantu, lezi Ukuhwebelana kungaba phakathi amathathu nanhlanu kuya ayisithupha nesithupha. Waba yini umphumela walesi nqubo heterogeneity genetic okuholela impahla, noma kokuhlukana gametes.

Lapho kuza diplotene esiteji of chromatids ezine izakhiwo ubhubhe udade Ama-chromosomes e vzaimoottalkivayutsya. Diakinesis uqeda yenguquko ukusuka prophase ukuze metaphase.

2. Metaphase: Ama-chromosomes e iyahambelana iseduze nenkabazwe esitokisini.

3. Anaphase: Ama-chromosomes e, namanje ehlanganisa chromatids ezimbili washintsha ukuze imijabo iseli.

4. Telophase: sokuhlukanisa lokuphotha uyabhujiswa, okuholela kwetinhlavu amaseli ezimbili neqoqo haploid wama-chromosomes kokuba kabili inani DNA.

Eyesibili division meiotic

Le nqubo ibizwa nangokuthi "mitosis, meiosis." Esikhathini mzuzu phakathi izigaba ezimbili-DNA ukuphindaphindeka ingekho, futhi ingqamuzana yesibili kungena prophase of isethi efanayo Ama-chromosomes e, okuyinto wahlala emva 1 telophase.

1. Prophase: Ama-chromosomes e cindezela maqembu ngokwahlukana iseli isikhungo (izinsalela zalo zehluke izinti iseli), kanye emgodleni ehlala nucleus kwakhiwa division lokuphotha ngokufanele perpendicular lokuphotha besigaba sokuqala.

2. Metaphase: Ama-chromosomes e zitholakala enkabazwe, yakheke metaphase ipuleti.

3. Anaphase: Ama-chromosomes e zihlukaniswe chromatids ukuthi akhipha kuzo zonke izindawo.

4. Telophase: chromatids core ngendodakazi amaseli kwakhiwa dispiralized ku chromatin.

Ekupheleni esigabeni umzali kuseli eyodwa yesibili, sinalo ezingaphansi ezine neqoqo kwesigamu chromosome. Uma meiosis senzeka ngokuhlanganyela umugqa lwegciwane (okungukuthi, ukwakheka kwamaseli ubulili), yilelo nalelo libe nesigaba kukhona ngqo engalingani, futhi kwakheka ngu kuseli eyodwa neqoqo haploid wama-chromosomes futhi ezintathu ukunciphisa ithole, ongathwali imininingwane edingekayo yezakhi zofuzo. Ziyakwazi kudingekile ukuze kube nesiqiniseko ukuthi iqanda nesidoda wahlala kuphela kwesigamu izinhlayiya eziyisisekelo zofuzo yeseli umzali. Ngaphezu kwalokho, lolu hlobo division inuzi inika ukubukeka inhlanganisela ezintsha zofuzo, kanye ifa oluhlanzekile alleles.

In the version olula meiosis ukhona lapho kukhona eyodwa kuphela ibha esigabeni sokuqala, futhi yesibili kukhona crossover. Ososayensi babonisa ukuthi lesi fomu eyandulela yokuziphendukela kwemvelo meiosis ezivamile eziphilayo ezinamangqamuzana amaningi. Mhlawumbe kukhona nezinye izindlela ukuqoqwa kwemibhalo, ososayensi musa kakazi.