Ukubunjwa, Imfundo Secondary nezikolo
Meiosis nezigaba zawo. izigaba uphawu meiosis. Veliswa eziphilayo. Ukufana mitosis kunye meiosis
Malunga eziphilayo, kuyaziwa ukuba uphefumle, badle, ziyazala sife, lo msebenzi ababazalayo. Kodwa ngenxa kokuba konke kwenzeka ntoni? Oko kusenziwa ngokudlela indlala iibhloko zokwakha - iiseli, nayo leyo ukuphefumla, badle, ziqhame sife. Kodwa kwenzeka njani oku?
Ubume yeseli
Le nto ndiyibhalayo kwezitena, iibhloko okanye logs. Ke umzimba lungahlulwa-hlulwa zibe kumacandelo ezinesiqalelo - iiseli. Zonke zezinto eziphilayo ngenxa yabo, umahluko ubuxoki kuphela inani labo kunye nohlobo. Ziqulethe imisipha, ithambo, ulusu, amalungu zangaphakathi - kangangokuba ahluke ngokuqesha zabo. Kodwa kungakhathaliseki ukuba yintoni imisebenzi yenziwa enye okanye enye iseli, bonke bephela zicwangciswe malunga efanayo. Okokuqala, naziphi "yezitena" sele iqokobhe kwaye ibekwe kwi icytoplasm kunye organelles yayo. Ezinye iiseli azinayo nuclei, zibizwa prokaryotic, kodwa ngaphezulu okanye uphuhliso ngaphantsi kwe eziphilayo lenziwe eukaryotic ukuba nucleus apho ulwazi yemfuza igcinwe.
Organelles akhiwe kukho icytoplasm, ezininzi nezibangel 'umdla, enza imisebenzi ebalulekileyo. Xa isilwanyana cell reticulum endoplasmic, ribosomes, mitochondria, izixhobo Golgi, centrioles, lysosomes nezinto basafunda. Nabo beze zonke iinkqubo ukuqinisekisa ukusebenza komzimba.
umsebenzi cell
Njengoko sele kuchaziwe, onke feeds ubomi, ephefumlayo, iphinde izivelise kwakhona aze afe. Oku kuyinyaniso zombini lonke kumzimba, oko kukuthi, abantu, izilwanyana, izityalo kunye njalo njalo. D., Yaye iiseli. Iyamangalisa, kodwa elowo "ngezitena" liye ubomi zayo. Ngenxa organelles yalo ifumana kwaye benzise izondlo, ioksijini, isusa zonke ngaphandle kwemfuneko. Uthi kukho icytoplasm kunye reticulum endoplasmic enze umsebenzi zothutho, mitochondria banoxanduva kuquka ukuphefumla, kwakunye yokhuseleko amandla. Golgi complex inxaxheba nokwanda output iiseli ezingasafunekiyo. Ezinye organelles nabo inxaxheba kwiinkqubo ezintsonkothileyo. Yaye kwinqanaba elithile lomjikelo wobomi iseli liqala ukuba zahlule, ngoko kukho inkqubo yokuzala. Iyafuna ingqalelo ngokweenkcukacha ezingakumbi.
Inkqubo yokwahlukana cell
Ukuzala - omnye amanqanaba uphuhliso esiphilayo. Kukwasebenza kwanjalo kuyo iiseli. Ngelo kwisigaba esithile lomjikelo wobomi zibandakanywa urhulumente xa sele ekulungele ukuzala. iiseli Prokaryotic mbaxa nje ezimbini, sandisiwe, uze ngokwakha umqobo. Le nkqubo ilula kwaye phantse iqondwe ngokupheleleyo umzekelo iintsholongwane intonga-ezimile.
Ekubeni iiseli eukaryotic imeko inzima kakhulu. Zizalela ngeendlela ezintathu ezahlukeneyo, ekuthiwa amitosis, mitosis kunye meiosis. Nganye kwezi iindlela uneempawu zawo, oko sizalwa uhlobo oluthile weseli. amitosis
Ngamanye amaxesha ukwahlulwa ngqo ofunyenweyo uhlobo mitosis, kodwa ezinye izazinzulu zikholelwa ukuba yindlela eyahlukileyo. Ikhosi yale nkqubo, nkqu iiseli ezindala kunqabile. Okulandelayo iya kuqwalaselwa meiosis nezigaba zawo, inkqubo mitosis kwakunye iimfano neeyantlukwano phakathi ezi ndlela. Xa kuthelekiswa ne candelo alula intsonkothe ngaphezulu abachubekileyo. Oku ngakumbi division lokwenyaniso ukwehla, ukuze izigaba meiosis Uphawu yeyona eneenkcukacha.
Indima ebalulekileyo eqeleni kwiseli na centrioles - organelles ethile, ngokuqhelekileyo zibekwe kufutshane enezakhiwo Golgi. isakhiwo nganye iqulathe microtubules-27 abahamba ngabathathu. Ukuma yonke ngokumila zezindlu. Le centrioles abanenxaxheba ngokuthe ngqo ekubunjweni iiseli yokusonta kwinkqubo sesahlulo ngqo, nto leyo eza kuxutyushwa ngakumbi.
mitosis
Ixesha iseli lohlukile. Abanye baphila iintsuku ezimbalwa, kodwa ezinye ekunokuthiwa ixesha elide, ngenxa utshintsho kwabo ngokupheleleyo lwenzeka kunqabile kakhulu. Kwaye phantse zonke ezi seli zande nge mitosis. Inkoliso yabo phakathi ixesha esayenza ngokomyinge iiyure 10-24. Mitosis ngokwayo ithatha ixesha elincinane ixesha - izilwanyana malunga 0.5-1
Ixabiso le hlobo candelo mkhulu - le nkqubo inceda ukuze akhule kwaye ukuntshula zomzimba, apho kukho uphuhliso yonke eziphilayo. Ukongeza, kuba sisiseko mitosis ukuzala maqanda. Kwaye enye inkalo - ukuhamba iiseli kunye nokutshintshwa sele wawungasasebenzi. Ngoko ke, sikholelwa ukuba ngenxa yokuba kweqonga meiotic nzima, ngoko indima yayo kakhulu engalunganga ngaphezulu. Zombini ezi nkqubo kufuneka imisebenzi ezahlukeneyo kunye ezibalulekileyo zazo yaye ezinye endaweni yazo.
Mitosis iqulathe izigaba ezininzi, ezahlukeneyo iimpawu zazo morphological. Urhulumente apho iseli ilungiselelwa ulwahlulo ngqo, ekuthiwa interphase, kunye nenkqubo ngokwayo wahlulwe ngamabanga-5, ekufuneka kuqwalaselwe iinkcukacha.
Izigaba mitosis
Xa iseli interphase ilungiselela division: i Yindibanisela DNA kunye neeproteni. Eli nqanaba libizwa yohlulwe eziliqela, apho kukho ukukhula ngesakhiwo chromosome yonke buya. Kule meko, iseli uhlala ukuya kwi-90% umjikelo wobomi yonke.
I-10% likhupha ngqo sigaba yahlulwe amanyathelo 5. Xa mitosis kweeseli zezityalo ekhutshwayo nayo Preprophase, apho angekhoyo zonke ezinye iimeko. Ukuyilwa kwezakhiwo ezitsha, undoqo uyasuswa uye kwiziko. Senziwe preprophase band, phawula site okucetywayo candelo kwixesha elizayo.
Kanti ezinye iiseli inkqubo mitosis imi ngolu hlobo lulandelayo:
itheyibhile 1
| igama isigaba | feature |
| prophase | I kernel lukhula ubukhulu, kuba spiralizuyutsya zofuzo sibonakale phantsi ngemicroscope. Le kukho icytoplasm kwakheka division yokuluka. Kudla kukho sokonakalisa le nucleolus, kodwa akusoloko kwenzeka. Umxholo genetic material esiseleni kuhlala ingatshintshanga. |
| prometaphase | Kukho sokonakalisa le ndizayo yenyukliya. Zofuzo ziqala intshukumo esebenzayo kodwa ingalawuleki. Ekugqibeleni, bonke beza-moya metaphase nembasa. Eli nqanaba ihlala ukuba imizuzu ukuya ku-20. |
| metaphase | zicwangciswe ecaleni moya sentshinyela intonga yokusonta malunga equidistant evela izibonda ezimbini The zofuzo. Inani microtubules, ephethe isakhiwo iphela a sizinzile, ifikelela ubuninzi. chromatids udade dudula omnye komnye, ukugcina uqhagamshelwano centromere. |
| anaphase | Inkundla imfutshane. Chromatids yahlukanisiwe kwaye ukubuyiselana kwicala zezibonda ekufutshane. Le nkqubo maxa wambi ebizwa ekwanti ngokwahlukeneyo yaye anaphase A. Ngapha koko kukho ukungangqinelani hlula izibonda ngokwabo. Iiseli ethile elula division edibanise ahambise ubude ukuya izihlandlo ezili-15. Kwaye oku sub-nyathelo kuthiwa anaphase B. Ubude nolandelelwano iinkqubo kweli nqanaba libizwa yomahluko. |
| telophase | Emva kokuba kuvalwe nezibonda elijongene chromatids divergence ukuyeka. zofuzo Decondensation kwenzeka, oko kukuthi, bandile ubukhulu. Iqala kuvuselelwa kweqokobhe zenyukliya iiseli elizayo intombi. Microtubule othini shwaka. umphakathi senziwe iphinde RNA yokuqaphela. |
Emva kokugqiba i-hlula yemfuza ulwazi cytokinesis kwenzeka okanye cytokinesis. Eli gama libhekisela nokusekwa imizimba iiseli intombi emzimbeni sikanina. Ngoko organelles yahlulwe ngokubanzi kubini, nangona kusenokubakho iimeko, ulwahlulo yenziwe. Cytokinesis alikho ngo kwisigaba eyahlukileyo, njengoko umthetho, ucinga ngayo njengenxalenye telophase.
Ngoko, kwi iinkqubo ezininzi umdla ebandakanya zofuzo nadlulisela ulwazi yemfuza. Yintoni na kwaye kutheni na kubaluleke kangaka?
malunga zofuzo
Nokuba ngaphandle kokuba ingcamango nakancinane yemfuza, abantu wayesazi ukuba abaninzi inzala umgangatho baxhomekeke kubazali babo. Ngophuhliso biology, kwaye kwacaca ukuba lo okanye ulwazi umzimba lugcinwe kwiseli nganye, yaye inxalenye ipasisiwe kwizizukulwana ezizayo.
Ekupheleni kwenkulungwane ye-19 ukuba zofuzo bafumanisa - izakhiwo eyenziwa elide
isakhiwo chromosome ngexesha xa ngokucacileyo ezibonakalayo, ilula - ngabo chromatids zimbini nabo phakathi centromere. It is a ulandelelwano ethile nucleotides kwaye lidlala indima ebalulekileyo kwisisele ukwanda. Ekugqibeleni chromosome ukhangela prophase kunye metaphase, xa kuya kuba ngcono ukubona, kufane H. incwadi
Ngowe-1900 kwafunyaniswa imithetho Mendel kaThixo, echaza imigaqo ekudluliseni imikhwa zamafa. Ke kwacaca ukuba zofuzo - oku nento ulwazi yemfuza idluliselwa. Kwixa elizayo, ezi oosonzululwazi baqhuba uthotho experimenti ukungqina oko. Kwaye ngoko yaba umxholo yokufunda kunye nefuthe kubo ukwahlulwa iseli buyout.
meiosis
Ngokwahlukileyo kulo indlela mitosis ekugqibeleni kukhokelela ukuyilwa ababini iiseli kunye iseti zofuzo amaxesha-2 mncinci kuno yokuqala. Ngaloo ndlela inkqubo meiosis na utshintsho kwisigaba ukusuka diploid ukuba haploid, apho kuqala
Meiosis kunye wo bafunda izazinzulu abaziwayo ezifana V. Fleming, E. Strasburgrer VI Belyaev kunye nabanye. Uphononongo yale nkqubo kwi iiseli izityalo kunye nezilwanyana, usaqhubeka - ngoko ke intsonkothile. Ekuqaleni, le nkqubo ingqalelo uhlobo mitosis, Noko ke, ngokukhawuleza emva kokuba kuvulwe ke esatsho bodwa njengendlela eyahlukileyo. Iimpawu meiosis kunye nexabiso theoretical component bachazwa kuqala ngokwaneleyo Augustus Wiseman ngo-1887. Ukususela ngoko, ukufunda kwinkqubo meiosis inkqubela kakhulu, kodwa ke iziphumo ziye okwangoku, wawancamisa ekuhleni.
Meiosis akukho mazingabhidaniswa umgca intsholongwane le, nangona zombini iinkqubo ezinxulumene ngokusondeleyo. Xa ukuyilwa iiseli ngesondo, zombini iindlela inxaxheba, kodwa ke kukho ezinye umahluko omkhulu phakathi kwabo. Meiosis kwenzeka amanyathelo ezimbini yokwahlula nganye equka izigaba ezine eziphambili, besathathe ikhefu elifutshane phakathi kwabo. Ubude yonke inkqubo kuxhomekeke kubungakanani iDNA ngumongo kwaye ubume bombutho chromosomal. Ngokubanzi, oko elide kakhulu elide ngakumbi xa kuthelekiswa mitosis.
Phela, omnye unobangela ezinkulu iyantlukwano iintlobo ezibalulekileyo - loo meiosis. Cwangcisa zofuzo ngenxa yoqhekeko ukwehla yahlulwe kubini, ukuze ukuba kukho imixube emitsha yemfuza, ingakumbi nesinamandla okwandisa bhetyebhetye nokuba nokuziqhelanisa eziphilayo, ngenxa ofumana ezithile iimpawu kunye neempawu.
Izigaba meiosis
Njengoko sele kukhankanyiwe, iyantlukwano ukuncitshiswa-iseli ngokuqhelekileyo yahlulwe nezigaba ezibini. Nganye kwezi zigaba yahlulwe ngo 4 Yaye ke isigaba sokuqala meiosis - prophase mna, yena, yahlulwa ngezigaba 5 ezahlukeneyo. Ukususela sifundo sale nkqubo iqhubeka, oko angahlangani nabanye kwixesha elizayo. Ngoku ukwahlula ezi zigaba zilandelayo meiosis:
itheyibhile 2
| igama isigaba | feature |
| Icandelo lokuqala (Ukunciphisa) | |
prophase I | |
| leptotena | Ngenye indlela, le nqanaba libizwa ngokuba iqonga imicu emihle. Le zofuzo kuvela ngemicroscope nje tangle. maxa wambi Proleptotenu ihlaba xa imitya ngamnye kusenzima ukuba bacalule. |
| elilodwa | Inyathelo ekuhlanganiseni kwayo. Homologous, oko kufana omnye komnye morphology kwaye zemfuza, iperi zofuzo coalesce. Ebudeni ngokudibana, okt conjugation eyakhiwe bivalents okanye tetrads. Ngoko wabiza izakhiwo ngokulinganayo nokuzinzileyo kwisibini zofuzo. |
| noPaquita | Inyathelo kwayo zamafu. Kweli nqanaba spiralizuyutsya chromosome DNA ukuphindaphindeka igcina kwakhiwa chiasma - zoqhagamshelwano iindawo indawo zofuzo - chromatids. inkqubo owelela Going. Zofuzo ukuba wawela baza ezinye iinkalo zolwazi yemfuza. |
| diplotene | Kwakhona wabiza isigaba imicu kabini. bivalents chromosome Homologous ukubuyiselana kwaye zisala enxulumene kuphela chiasm. |
| diakinesis | Kweli nqanaba bivalents diverge kwi kwimiphetho isiqalo. |
| metaphase I | kuwa shell core kwakhiwa division yokuluka. Bivalents safudukela embindini iseli yaye aqondwe ecaleni moya zemvula. |
| anaphase I | Bivalents yaphela, apho chromosome nganye kwisibini uyasuswa uye iseli esibondeni elikufutshane. Chromatid ngokwahlukana akwenzeki. |
| telophase I | Inkqubo chromosome ukuhlukana. Ngaba ukuyilwa eziba ngamnye iiseli intombi, nganye - isethi haploid. Zofuzo dispiralized kwasekwa imvulophu yenyukliya. Ngamanye amaxesha kukho cytokinesis, okt ukwahlulwa komzimba cell. |
| Icandelo lesibini (equational) | |
| prophase II | Chromosome amafu kwenzeka, iziko iseli yahlulwe. Litshatyalaliswa imvulophu yenyukliya. Kwakhiwa othini division, aa Incopho kowokuqala. |
| metaphase II | Kwimeko nganye kwezi nkampani zofuzo aqondwe ecaleni ikhweyitha esiseleni. Ngamnye kubo luquka chromatids ezimbini. |
| anaphase II | chromosome nganye yahlulwe chromatids. La malungu diverge kwiipali esahlukileyo. |
| telophase II | Le chromosome odnohromatidnye ifunyenwe dispiralized. Senziwe imvulophu yenyukliya. |
Ngoko ke, kuyacaca ukuba izigaba kwisahlulo meiosis kuba nzima ngaphezu inkqubo mitosis. Kodwa ke, njengokuba sele kukhankanyiwe, oku kunciphisa indima bemvelo sisahlula ngqo, ngenxa yokuba imisebenzi eyahlukeneyo.
Hi ndlela leyi, meiosis kunye nezigaba zawo kuvandlakanywa ezinye elula. Noko ke, ngokuqhelekileyo lubandakanya hlula enye kuphela. Kuthathwa ukuba kamva le fom olunye-nqanaba yaba mihla, enezigaba ezibini.
Iiyantlukwano neemfano phakathi mitosis kunye meiosis
Ngophanya nje lweliso, kubonakala ukuba umahluko phakathi kwezi nkqubo zimbini zisekuhleni kanye, ngenxa yokuba iindlela ezahlukeneyo ngokupheleleyo. Kodwa ke, uhlalutyo olunzulu ityhila ukuba ukungaboni mitosis kunye meiosis azikho jikelele ngoko ke, ekugqibeleni kukhokelela ukuyilwa iiseli ezintsha.
Okokuqala kuyimfuneko ukuthetha izinto ezifanayo phakathi kwezi ndlela. Enyanisweni imidlalo kuphela ezimbini: ngokulandelelana kwisigaba enye, ngokunjalo ukuba
Umahluko omkhulu kakhulu. Kuqala kwinto zonke, mitosis kwenzeka iiseli somatic, ngexesha meiosis ixhulumane ngokusondeleyo kunye nokusekwa gametes kunye sporogenesis. Izigaba yeenkqubo ngokwabo idibana ngokupheleleyo. Umzekelo, kwibhulorho-over in mitosis kwenzeka ngexesha interphase, yaye emva koko akusoloko. Noko ke, Kwimeko yesibini, le nkqubo kufuneka ukuba anaphase of meiosis. gene recombination kwisahlulo ngqo akukho ngokuqhelekileyo luqhutywa, nto leyo ethetha ukuba ayenzi ukudlala nayiphi indima kwemvelo yento ephilayo kunye nokugcinwa iyantlukwano intra-ntlobo. Inani onesiphumo kwizisele mitotic - ezimbini, yaye zofuzo twatse ingqiqo koomama, yaye iseti diploid zofuzo. Ngexesha meiosis ezahlukeneyo. Isiphumo meiosis - 4 iiseli haploid, eziya kwahluka evela kumzali. Ngaphezu koko, zombini iindlela ziyahluka kakhulu ngokobude, kwaye oko kunxulumene hayi kuphela umahluko inani lamanyathelo candelo, kodwa ke ixesha kwinqanaba ngalinye. Umzekelo, ukuba prophase yokuqala meiosis ithatha ixesha elide kakhulu, kuba ngeli xesha kukho synapsis kunye ukuwela. Kungenxa yoko le nto sahlulwe ngokwamanqanaba eziliqela.
ukufana kukonke mitosis kunye meiosis ngokwaneleyo ezincinane kuthelekiswa iiyantlukwano zabo omnye komnye. Edidekile ezi nkqubo phantse nzima. Ngoko ke ngoku wamangaliswa ukuba ukwahlulwa ukwehla ngaphambili sele ingqalelo uhlobo mitosis.
Imiphumo meiosis
Njengoko sele kukhankanyiwe, emva kokuba inkqubo meiosis kunokuba iiseli koomama kunye chromosome diploid njengoko ifom ezine haploid. Kwaye ukuba siye sithethe malunga kumahluko mitosis kunye meiosis - oku yeyona ibalulekileyo. Ukufunyanwa kwe inani elifunekayo, kwimeko iiseli intsholongwane lwenzeka emva kokukhulelwa. Ngenxa yoko, nge isizukulwana ngasinye esitsha lungenzeki ngokuzenzekela kwaye kabini inani zofuzo.
Ngapha koko, ngexesha recombination meiotic kwenzeka yemfuza. Kwinkqubo yokuzala, oku kukhokelela kulondolozo lweyantlukwano intra-ntlobo. Ngoko ke into yokuba abazalwana noodade ngamanye amaxesha ahlukeneyo kakhulu enye kwenye - sisiphumo meiosis.
Ngendlela, ukuba inzalo ka ngxilimbela ezithile ehlabathini isilwanyana - nayo ingxaki sisahlula ukuncitshiswa. Isibakala sokuba zofuzo abazali akwi iintlobo ezahlukeneyo awukwazi ukungena conjugation kwaye ngenxa yoko, ukuyilwa iiseli lwegciwane ezinokwenzeka high-grade akwenzeki. Ngoko ke, oko meiosis kuba sisiseko sophuhliso yendaleko izilwanyana, izityalo kunye nezinye izinto.
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