Zoberekera ntchito ndi tanthauzo zamoyo meiosis

Ntchito ubereki wabwino wa thupi ikuchitika pa kugwirizana gametes awiri (maselo nyongolosi) kukachitika ndi chitukuko wotsatira wa thupi wocheperapo zygote - umuna dzira. Mu makolo kugonana maselo mukhale ndi ena a N-DNA. Iye anaitana haploid. Zygote ukuchitika ya izi, ndi diploid selo, ie, khromozomu chiwerengero 2n kumeneko: akuchikazi limodzi ndi makolo wina. Tizilombo meiotic magawano lofunika kwambiri monga pa selo lili mu choona kuti chifukwa izo, selo haploid anapanga ku maselo diploid.

tanthauzo

Meiosis mu zamoyo amatchedwa mtundu wa mitosis; chifukwa chake diploid maselo somatic wa zopangitsa zoberekera anawagawa gametes 1n. Pamene ngale ndi ukala, pali maphatikizidwe wa gametes. Choncho, akutsitsimuka 2n khromozomu akonzedwa. Tanthauzo la meiosis ndi kuonetsetsa kuteteza wa chibadidwe uliwonse wa zamoyo DNA ndi yaikulu yoyenera DNA.

mafotokozedwe

Meiosis - ndondomeko ndi mosalekeza. Amakhala ndi mitundu iwiri ya kugawa successively zotsatirazi mzake: meiosis Ine ndi meiosis II. Aliyense wa njira Zikatero, imakhala prophase, metaphase, anaphase, telophase. Wa gulu loyamba meiosis kapena meiosis Ine, amachepetsa chiwerengero DNA, i.e. pali chodabwitsa otchedwa magawano kuchepetsa. Pamene gawo lachiwiri la meiosis kapena meiosis II, maselo haploid si zingasokoneze kusinthaku, kwasungidwira. Zimenezi amatchedwa equational magawano.

maselo onse siteji ya meiosis, amanyamula mudziwe mlingo chibadwa.

• Meiotic prophase wa choyamba - siteji mwapang'onopang'ono helix chromatin ndi mapangidwe DNA. Kumapeto kwa chilichonse zovuta zakuthupi majini pano mu maonekedwe ake apachiyambi - 2n2 DNA.
• Metaphase akubwera - amabwera mlingo pazipita helix. Nkhani majini akadali sanasinthe.
• Anaphase wa meiosis limodzi ndi kuchepetsa a. Mugulu DNA makolo wopatsa mmodzi wa maselo ake wamkazi. zakuthupi majini lisinthike zikuchokera, monga khromozomu chiwerengero anali theka kuti: lililonse mzati wa khungu ndi zofunika 1n2 khromozomu.
• Telophase - gawo pamene kupanga pachimake, anapambulwa cytoplasm. maselo mwana analengedwa, ali 2 ndipo aliyense wa chromatids awiri. Ie anapereka DNA mu haploid iwo.
• interkinesis ananenanso, kupuma pang'ono pakati pa gawo loyamba ndi lachiwiri la meiosis. Maselo awiri wamkazi ali okonzeka kulowa Gawo lachiwiri la meiosis, kumene kumachitika mwa njira zofanana ndi za mitosis.

Tanthauzo zamoyo meiosis Choncho chakuti mogwirizana wake wachiwiri mwa njira zovuta kale anapanga maselo haploid 4 - 1n1 DNA. Ie, wina diploid mayi selo amapereka moyo kwa anayi - lililonse haploid khromozomu akonzedwa. Mu oyamba gawo meiotic digiri zinthu majini recombines, ndi chinthu chachiwiri ikuchitika kayendedwe ka DNA ndi chromatids kwa mizati osiyana selo. Izi kayendedwe - gwero la kusintha ndi ma osiyanasiyana intraspecific.

zotsatira

Motero, tanthauzo zamoyo meiosis, kwenikweni chachikulu. Choyamba, tisaiwale monga waukulu, gawo lalikulu la Genesis gametes. Meiosis anaonetsetsa kulanda mudziwe majini ku mtundu chamoyo ndi mzake, malinga kubereka pogonana ndi. Meiosis chimathandiza intraspecific osakaniza zimachitika chifukwa maselo mwana amasiyana osati cha makolo komanso amasiyana.

Komanso, tanthauzo zamoyo meiosis tichipeza mu kupereka kuchepetsa DNA nthawi imene maselo nyongolosi anapanga. Meiosis zipangitsa haploid awo; pa nthawi ya umuna imene zygote diploid khromozomu dongosolo wabwezeretsedwa.