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Sabzish va taqsimshavii hujayra

Olimon sokhti hujayraro bo yorii mikroskop omukhta, mushohida kardand, ki hujayrai aksari uzvhoi rastani qobiliyati sabzida ba kamol rasidan va taqsim shuda afzoish kardanro dorad. Dar natija hujayrahoi nav ba vujud meoyand.

Taqsimshavii hujayra odatan khele murakkab meguzarad. Saravval, yadroi hujayra kalon shuda, dar on khromosomaho, ki jismchahoi oda- tan zugutashakl yo silindriand va alomathoi irsiro az hujayra ba hujayrai nav bavujudomada meguzaronand, duchand meshavand va ba khubi ayon megardand 16 .

Badi joyivazkunihoi murakkab nisfi khromosomaho ba yak qutbi hujayra va nisfi digarash ba qutbi digari on joy ivaz mekunand. Dar qutbho du yadroi nav paydo meshavad, ki mikdori khromosomahoi har kadomi onho ba mikdori khromosomahoi dar yadroi pesh ba taq- simshavi shurukardai khujayrai modari barobar ast.

taqsimshavii-hujayra

Dar in vaqt dar dokhili (yo mobayni) sitoplazmai hujayrai taqsimshudaistoda plastinka (lavhacha) paydo meshavad. Vay hujayraro ba du qismi barobar taqsim mekunad va dar har kadomi in qismho yake az yadrohoi bavujudomada joygir meshavad. Tamomi moddahoi zindai hujayra niz dar bayni in du hujayrai javon (nav paydoshuda) barobar taqsim meshavand. Hamin tavr, dar natijai taqsimshavi az yak khujayrai modari du hujayrai javon (dukhtari) ba vujud meoyad .

Taqsimshavii khujayra dar baze holatho va dar baze organizmhoi rastanigi be joyivazkunii murakkabi khromosomaho niz ruy dodanash mumkin ast. Dar in holatho yadro va sitoplazma bevo sita ba du hissa chudo shuda, du hujayrai navro ba vujud meovarand.

Hujayrahoi javon az hujayrahoi pir bo baze alomathoyashon farq mekunand. Andozai onho khurd buda, asosan az sitoplazma pur meboshand va inchunin, bisyor vakuolahoi khurd dorand. YAdroi khujayrai javon dar mobayni hujayra joy giriftaast. Hujayrai kalon (pir) odatan yak vakuolai kalon va sitoplazma dorad. Dar sitoplazma yadro joygir ast, ki ba lifofai hujayra jafs ast.

Hamin tavr, taqsimshavii hujayra az taqsimshavii yadro ogoz meyobad va mikdori khromosomahoi har kadom yadroi du hujayrai javon (nav) va yadroi hujayrai avvala (to taqsimshavi) barobarand. Hujayrahoi javoni az nav bavujudomada mesabzand, darozruya meshavand, ba andozai hujayrahoi bolig rasida, khudashon ham ba taqsimshavi shuru mekunand. Hamai uzvhoi rastani (resha, poya, barg, gul va gayraho) bo tufayli taqsimshavi va kalonshavii hujayraho mesabzand va qad mekashand 17 .

  1. Hujayra chi tavr taqsim meshavad?
  2. Dar vaqti taqsimshavii hujayra bo yadro chi hodisa ruy medihad?
  3. Hujayrahoi javon az hujayrahoi pir chi farq dorand?
  4. Sabzishi uzvhoi rastaniro chi guna metavon sharh dod?
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