Meiosis ndi magawo ake. magawo khalidwe la meiosis. Kubalana wa zamoyo. Kufanana mitosis ndi meiosis

About zamoyo, amadziwika kuti kupuma, kudya, kubereka ndi kufa, ili ndi ntchito zawo kwachilengedwenso. Koma chifukwa chimene zonsezi zikuchitika? Likuvutika nyumba zingatipunthwitse - maselo, amenenso kupuma, kudya, kubereka ndi kufa. Koma zimenezi zimachitika bwanji?

Kapangidwe ka khungu

Iwo wapangidwa ndi njerwa, midadada kapena zipika. Ndipo thupi akhoza kugawidwa mu mayunitsi pulayimale - maselo. zosiyanasiyana onse a zinthu zamoyo ndi chifukwa cha iwo, kusiyana lili okha chiwerengero chawo ndi mtundu. Iwo amakhala ndi minofu, fupa, khungu ziwalo - kwambiri iwo amasiyana paudindo. Koma mosasamala chimene ntchito zimagwiridwa ndi limodzi kapena foni wina, onse a iwo anakonza za chomwecho. Choyamba, aliyense "njerwa" ali ndi chipolopolo ndi pabwino mu cytoplasm ndi organelles ake. Maselo ena alibe mtima, iwo amatchedwa prokaryotic, koma ndi zambiri kapena zochepa chitukuko cha zamoyo wapangidwa eukaryotic kukhala phata imene mudziwe majini awasungira.

Organelles ili mu cytoplasm, ndi zosiyanasiyana komanso zosangalatsa, iwo amagwira ntchito zofunika. Nyama maselo secrete endoplasmic reticulum, ribosomes, mitochondria, zida Golgi, centrioles, lysosomes ndi zinthu zosagwiritsa. Ndi iwo anabwera njira zonse kuonetsetsa kugwira ntchito kwa thupi.

ntchito foni

Monga tafotokozera kale, onse Zingayambe moyo, amapuma, imabereka ndi kufa. Izi ndi zoona kwa onse chamoyo lonse, ndiwo anthu, nyama, zomera ndi zina zotero. D., Ndipo kwa maselo. Ndi zodabwitsa, koma "njerwa" ali ndi moyo zake. Chifukwa organelles ake amalandira ndi recycles zakudya, mpweya, amachotsa onse owonjezera. Iye cytoplasm ndi endoplasmic reticulum kuchita ntchito zoyendera mitochondria ndi udindo kuphatikizapo kupuma, komanso chitetezo mphamvu. Golgi zovuta nawo kudzikundikira ndi linanena bungwe maselo a zinthu zotha. The organelles ena akugwira nawo ntchito njira zovuta. Ndipo pa siteji ena a mayendedwe amoyo selo imayamba kugawanitsa, ndiye pali ndondomeko kubalana. Ndi zothandiza mwatsatanetsatane.

The ndondomeko ya kugawikana selo

Kubalana - mmodzi wa magawo chitukuko cha zamoyo. N'chimodzimodzinso ndi maselo. Pa siteji ena a mayendedwe amoyo ali m'gulu boma pamene iwo kukhala wokonzeka kawetedwe. maselo Prokaryotic chabe m'magulumagulu awiri, anawonjezera, ndiyeno kupanga chotchinga. Zimenezi yosavuta pafupifupi bwinobwino Chitsanzo mabakiteriya ndodo woboola pakati.

Popeza maselo eukaryotic zinthu zovuta. Iwo zimaswana mwa njira zitatu zosiyana, wotchedwa amitosis, mitosis ndi meiosis. Aliyense wa njira awa ali ndi makhalidwe ake, ndi chibadidwe mu mtundu winawake wa khungu. amitosis Amaona mophweka kwambiri, limatchedwanso lachindunji bayinare fission. Pamene pali anawaonjezera kuwirikiza kawiri wa DNA. Komabe, magawano spindle si anapanga, kotero kuti njira imeneyi ndi ambiri ankafalitsa mwakhama ndalama. Amitosis anamuona pa zamoyo unicellular, pamene multicellular minofu kufalitsa kudzera njira ina. Komabe, nthaŵi zina anaona ndiponso pamene yafupika mitotic ntchito Mwachitsanzo, mu zimakhala okhwima.

Nthawi zina gulu mwachindunji anachira monga mawonekedwe a mitosis, koma asayansi ena amakhulupirira ndi njira zosiyana. Mayendedwe a ndondomeko imeneyi, ngakhale mu maselo akale ali osowa. Kenako tikambirana meiosis ndi magawo ake, ndondomeko mitosis komanso kufanana ndi kusiyana pakati pa njira izi. Poyerekeza ndi kugawikana yosavuta ali ovuta kwambiri ndi zovuta kuzimvetsa. Izi makamaka woona kuchepetsa magawano, kotero kuti mbali ya meiosis khalidwe ndi mwatsatanetsatane kwambiri.

Yofunika kwambiri Gulu selo centrioles - organelles yeniyeni, kawirikawiri kufupi ndi Golgi zovuta. Aliyense dongosolo tichipeza microtubules 27 m'magulu zitatu. Dongosolo lonse ali ndi mawonekedwe cylindrical. centrioles The amagwira ntchito mapangidwe maselo spindle mu ndondomeko ya kugawikana mozungulira, tikambirana zina.

mitosis

Kutalika kwa selo zimasiyanasiyana. Ena moyo masiku angapo, koma ena akhoza zimachitika nthawi yaitali, chifukwa cha kusintha zawo zonse kumachitika kawirikawiri. Ndipo pafupifupi onse a maselo amenewa kubereka kudzera mitosis. Ambiri mwa iwo ndi pakati pa nthawi magawano anali pafupifupi maola 10-24. Mitosis yokha ali ndi nthawi yaing'ono ya nthawi - nyama za 0.5-1 ola, ndi zomera za 2-3. limagwirira Izi zipangitsa kuti kukula kwa chiwerengero selo ndi kubalana zofanana mu kudzazidwa awo majini mayunitsi. Choncho anati kupitiriza kwa mibadwo pa mlingo pulayimale. Pankhaniyi, topangira DNA akanali yemweyo. limagwirira Izi ndi yofala kwambiri kubalana maselo eukaryotic.

Mtengo wa mtundu wa Chigawo ndi lalikulu - ndondomeko zimenezi zimathandiza kukula ndi buluzi zimakhala, limene pali chitukuko cha chamoyo wonse. Komanso, ndi maziko a mitosis asexual kubalana. Ndipo china - kayendedwe ka maselo m'malo a kale ntchito. Choncho, ife tikukhulupirira kuti chifukwa chakuti siteji meiotic kwambiri, ndiye udindo wake ndi apamwamba kwambiri cholakwika. Onse a pasukuluyi ndi ntchito zosiyanasiyana komanso zofunika zawo ndipo irreplaceable.

Mitosis tichipeza magawo angapo, zimasiyanasiyana zizindikiro zawo morphological. boma limene selo kukonzedwa magawano mozungulira, wotchedwa interphase, ndi njira yokha lagawidwa ndi magawo 5 limene tiyenela kuiganizila mwatsatanetsatane.

Magawo mitosis

Ali interphase selo amakonzekera magawano: kaphatikizidwe wa DNA ndi mapuloteni. Mbali imeneyi lagawidwa angapo, mmene muli kukula kwa lonse kapangidwe ndi khromozomu anawaonjezera kuwirikiza kawiri. Mmenemonso, selo amakhala mpaka 90% ya lonse mkombero moyo.

Otsala 10% Pamafunika mwachindunji magawano lagawidwa masitepe 5. Pa mitosis la zomera maselo nawonso anamasulidwa Preprophase, amene ali kwina zina zonse. Mapangidwe nyumba yatsopano, pachimake n'kufuna kuti likulu. Anapanga preprophase gulu, chikhomo malo okonza a gulu m'tsogolo.

Komanso maselo ena mitosis zimachitika motere:

Table 1

Nditamaliza ndi kugawa majini mudziwe cytokinesis amapezeka kapena cytokinesis. Mawu amenewa amanena mapangidwe mitembo ya maselo mwana wamkazi kwa thupi la mayi. Choncho organelles ambiri agawidwa mu theka, ngakhale pangakhale kuchotserapo, kugawa aumbike. Cytokinesis si olekanitsidwa mu gawo osiyana, monga ulamuliro, kuganizira mbali ya telophase.

Choncho, mu njira chidwi kwambiri zokhudza DNA kuti timanyamula mauthenga chibadwa. Kodi ndi chifukwa iwo ali ofunika?

About DNA

Ngakhale popanda lingaliro pang'ono chibadwa, anthu ankadziwa kuti khalidwe ana amadalira makolo awo. Ndi chitukuko cha zamoyo, zinadziwika kuti pa izi kapena kuti mudziwe thupi kusungidwa mukachipinda, ndi gawo la icho chimapita ku mibadwo ya m'tsogolo.

Kumapeto kwa zaka za m'ma 19 zinali DNA anapeza - nyumba wopangidwa mwa yaitali DNA mamolekyulu. Izi kunatheka ndi kusintha kwa microscopes, ndipo ngakhale tsopano inu mukhoza kuwona iwo okha pa magawano. Nthawi zambiri akutchedwa atulukira German wasayansi V. Fleming, amene osati bungwe zonse aphunzira pamaso pake, koma anathandizanso: anali mmodzi wa oyamba kufufuza kapangidwe ma, meiosis ndi magawo ake, komanso anayambitsa mawu akuti "mitosis". Mfundo kwambiri za "khromozomu" anali akufuna asayansi kenako zina - ndi German histologist G. Heinrich Wilhelm Gottfried Von Waldeyer-Hartz.

khromozomu dongosolo pa nthawi imene ali kuoneka bwino, ndi wosavuta - iwo ali chromatids awiri likugwirizana pakati pa centromere lapansi. Ndi ndondomeko yoyenera ya nucleotides ndipo amagwira ntchito yofunika kwambiri mu kuchuluka selo. Potsilizira pake khromozomu akuyang'ana prophase ndi metaphase, pamene zingakhale bwino kuti mukuona, izo akufanana kalata H.

Mu 1900 anatulukira malamulo Mendel ndi kufotokoza mfundo za kufala kwa makhalidwe cholowa. Ndiye zinaonekeratu kuti DNA ndi - ichi ndi chinachake chimene mfundo majini ndi anasamutsidwa. M'tsogolo, asayansi anachita mndandanda wa zinthu zatsopano ndi kutsimikizira izo. Ndiyeno anakhala phunziro la ndi yaikulu iwo ali kugawanika buyout selo.

meiosis

Mosiyana ndi izi mitosis limagwirira mapeto mapangidwe maselo awiri ndi ya DNA nthawi 2 kakang'ono kuposa choyambirira. Choncho ndondomeko meiosis ndi gawo kusintha kwa diploid kuti haploid, mmene loyamba tikulankhula fission nyukiliya, ndipo lachiwiri - selo lonse. Kubwezeretsa kuika zonse DNA kumachitika mwa Zisudzo zina za gametes. Chifukwa cha kuchepa kwa chiwerengero DNA, njira imeneyi akadali limanenedwa ngati magawano kuchepetsa-selo.

Meiosis ndi magawo ake anaphunzira asayansi amenewa otchuka monga V. Fleming, E. Strasburgrer VI Belyaev ndi ena. Kuphunzira ndondomeko izi mu maselo a zomera ndi nyama, ndi kupitirirabe - kotero kobvuta. Poyamba, ndondomeko izi ankaona zosinthika wa mitosis Komabe, pasanapite nthawi kuchokera kutsegula kwa iye akadali anali yekhayekha monga limagwirira osiyana. Kaperekedwe meiosis ndi phindu lake ongolankhula anayamba mokwanira anafotokoza Augustus Wiseman mu 1887. Kuyambira pamenepo, kuphunzira ndondomeko meiosis kwambiri patsogolo, koma anapezazo ndi sizinachitike umboni.

Meiosis si lofanana ndi mzere nyongolosi, ngakhale njira zonse ndi zogwirizana kwambiri. Mu mapangidwe maselo kugonana, njira zonse zokhudza koma pali kusiyana kwakukulu pakati pawo. Meiosis amapezeka mu masitepe awiri nagawira yense wa chomwe mbali zinayi zikuluzikulu, ndi kupuma pang'ono pakati pawo. Kutalika kwa ndondomeko lonse zimadalira kuchuluka kwa DNA mu phata ndi dongosolo la chromosomal bungwe. Ambiri, ndi zambiri yaitali kwambiri zokhalitsa poyerekeza mitosis.

Zodabwitsa ndizakuti, chimodzi mwa zifukwa zikuluzikulu kwambiri mitundu yosiyanasiyana - kuti meiosis. Ikani DNA chifukwa cha kugawikana kuchepetsa lagawidwa pawiri, kotero kuti pali ma yatsopano imene imachititsa, makamaka zingakhale kuonjezera kusinthasintha ndi kusinthasintha kwa zinthu, chifukwa cha kulandira akonzedwa zina makhalidwe ndi makhalidwe.

Magawo meiosis

Monga tanenera kale, magawano kuchepetsa-selo conventionally kugawidwa mu magawo awiri. Aliyense wa magawo awa lagawidwa ndi 4. Ndipo ngakhale gawo loyamba la meiosis - prophase inenso, lophatikizana ndi ubwamunalo linagawanika mu magawo 5 osiyana. Popeza kuphunzira njira imeneyi, zikhoza olekanitsidwa ndi anthu ena m'tsogolo. Tsopano kusiyanitsa mbali zotsatirazi meiosis:

Table 2

Choncho, n'zoonekeratu kuti magawo meiosis magawano ndi ovuta kwambiri kuposa ndondomeko mitosis. Koma, monga tanenera kale, izi sasiya udindo zamoyo magawano mozungulira, chifukwa iwo ali ndi ntchito zosiyanasiyana.

Mwa njira, meiosis ndi magawo ake anamuona pa ena losavuta. Komabe, nthawi zambiri kumaphatikizapo Chigawo chimodzi chokha. Amaganiza kuti limodzi gawo mawonekedwe kenako anayamba mu masiku, tsatane awiri.

Kusiyana ndi kufanana pakati mitosis ndi meiosis

Koyamba zikuoneka kuti kusiyana njira awiriwa zoonekeratu, chifukwa iwo ali zimagwirira chosiyana. Komabe, kusanthula zakuya limasonyeza kuti kusiyana mitosis ndi meiosis sali choncho lonse, iwo kudzabadwira mapangidwe maselo atsopano.

Choyamba m'pofunika kuti alankhulepo za zomwe ndi zofanana pakati pa njira izi. Ndipotu machesi awiri okha: mu gawo ndondomeko yomweyo, komanso kuti pamaso magawano amapezeka mitundu onse a DNA kugawanika. Ngakhale za meiotic prophase Ine isanafike ndondomeko izi si bwino anamaliza, mathero pa limodzi la substages choyamba. A ndondomeko ya nthawi, ngakhale ofanana, koma zoona, chikuchitika mu chochitika samazindikira mokwanira mwamalunji. Choncho kufanana mitosis ndi meiosis sali choncho ambiri.

kusiyana ndi ochuluka kwambiri. Choyamba, mitosis amapezeka maselo somatic, pamene meiosis ndi umakhudza mapangidwe gametes ndi sporogenesis. Magawo njira eni okha kwathunthu mwamalunji. Mwachitsanzo, akuwoloka-mu mitosis zidzachitika interphase, ndiyeno zonse. Ngati chachiwiri, Koma ndondomeko ichi chiyenera anaphase wa meiosis. jini recombination Gulu mozungulira si nthawi zonse umachitikira, kutanthauza kuti si udindo uliwonse mu chitukuko zinachokera lake ndi yokonza zosiyanasiyana kwapakati pa-mitundu. chiwerengero cha chifukwa maselo mitotic - awiri, ndipo iwo ali osiyana ndi zimene tanthauzo akuchikazi, ndipo ndi diploid ya DNA. Pa meiosis osiyana. The chifukwa cha meiosis - 4 haploid maselo, amene amasiyana kholo la. Komanso, asilikali onse osiyana kwambiri m'litali, akufotokozereni osati kusiyana kwa chiwerengero cha masitepe magawano, komanso nthawi iliyonse siteji. Mwachitsanzo, prophase loyamba meiosis limapitirira kwambiri, chifukwa pa nthawi imeneyi pali synapsis ndi kudutsa. N'chifukwa chake zina kugawidwa mu magawo angapo.

kufanana kwa mitosis ndi meiosis Cacikulu mokwanira yochepa polingana ndi kusiyana kwawo Chrixitu. Kusokoneza njira izi kovuta. Kotero tsopano kwambiri anadabwa magawano kuchepetsa kale kale mawonekedwe mitosis.

Zotsatira za meiosis

Monga tanenera kale, pambuyo ndondomeko meiosis m'malo maselo akuchikazi ndi khromozomu diploid anapereka anayi haploid mawonekedwe. Ndipo ngati tikukamba za kusiyana mitosis ndi meiosis - izi ndi zofunika kwambiri. Ayambe chiwerengero chofunika, mu nkhani ya maselo nyongolosi pambuyo umuna. Choncho, ndi mbadwo uliwonse watsopano zimachokeradi ndi pawiri topangira DNA.

Komanso, pa recombination meiotic amapezeka chibadwa. Mu ndondomeko ya kubereka, zimenezi zimapangitsa kuti ntchito yokonza zosiyanasiyana kwapakati pa-mitundu. Kotero kuti ngakhale abale ndi alongo zina zosiyana kwambiri ndi mzake - chifukwa cha meiosis.

Mwa njira, sterility wa hybrids ena mu dziko nyama - ndi vuto kuimira kuchepetsa. chakuti DNA ya makolo yoperekedwa kwa mitundu yosiyanasiyana sakhoza kulowa conjugation choncho, mapangidwe apamwamba kalasi maselo yotheka nyongolosi sizingatheke. Choncho meiosis ndi maziko a chitukuko zinachokera nyama, zomera ndi zamoyo zina.