Kodi fission nyukiliya? fission Mitundu

Lililonse selo imayamba moyo wake pamene wosiyana kholo, ndipo akutsirizira kukhala, kupereka mwayi kuonekera kwa maselo awo mwana wamkazi. Nature njira zingapo za kugawa pachimake, malingana ndi dongosolo lawo.

Njira ya kugawikana selo

Kugawa pakati zimadalira mtundu selo ndi :

- bayinare fission (chopezeka prokaryotes).

- amitosis (yolunjika magawano).

- Mitosis (wamba mu eukaryotes).

- Meiosis (kwa kugawa maselo nyongolosi).

Mitundu fission atsimikiziridwa mwa chibadwa ndiponso zogwirizana ndi kapangidwe ka khungu ndi ntchito izo anachita macroorganism kapena palokha.

bayinare fission

Nthawi zambiri mtundu izi zimapezeka mu maselo prokaryotic. Amakhala mu anawaonjezera kuwirikiza kawiri pa zozungulira DNA. Bayinare fission wa phata ndi wotchedwa chifukwa cha foni mayi pali awiri mofanana kakulidwe mwana wamkazi.

Pambuyo nkhani majini (DNA kapena RNA molekyulu) anawakonzera moyenera, i.e. izo kawiri, kuchokera pampanda khungu amayamba ndi kugawa yopingasa, umene pang'ono ndi pang'ono tapered ndi cytoplasm ukugawa pawiri pafupifupi wofanana.

The chachiwiri kugawaniza ndondomeko amatchedwa budding kapena m'goli bayinare fission. Mu nkhani iyi, maselo makoma kuoneka protrusion gawo, yomwe pang'onopang'ono kukula. Pambuyo "impso" ndi kukula kwa selo mayi adzakhala ofanana, Amawapatula. gawo A a linga selo ndi apanga kachiwiri.

amitosis

Izi gulu la phata la ofanana ndi tafotokozazi, ndi kusiyana kuti palibe anawaonjezera kuwirikiza kawiri zakuthupi chibadwa. Njira anafotokozedwa koyamba Remak zamoyo. chodabwitsa kumachitika maselo pathologically adasandulika (zilonda kusinthika), ndipo linalake thupi kwa chiwindi minofu, chichereŵechereŵe ndi diso.

ndondomeko imatchedwa nyukiliya fission amitosis chifukwa selo akuzisunga ntchito yake, ndipo sasiya iwo monga pa mitosis. Nchifukwa chake katundu nthenda kugwirizana ndi ndondomeko magawano selo. Komanso mwachindunji magawano pakati akudutsa popanda spindle, kotero mwana maselo chromatin ndi anagawira uniformly. Mu izi, maselo amenewa sangathe ntchito kayendedwe ka mitotic. Nthawi zina, chifukwa cha amitosis anapanga maselo multinucleated.

mitosis

Izi mozungulira nyukiliya fission. Nthawi zambiri amapezeka mu maselo eukaryotic. Chachikulu kusiyana kwa ndondomeko izi kwagona kuti mwana ndi maselo akuchikazi muli nambalayi DNA. Kudzera mwa thupi imayendetsedwa ndi chiwerengero chofunika maselo, komanso zotheka kusinthika ndi kukula njira. The mitosis oyambirira selo nyama anafotokoza Flemming.

The ndondomeko ya kugawa phata mu nkhani iyi ndi wosiyana mwachindunji pa interphase ndi mitosis. Interphase - mkhalidwe maselo mpumulo pakati pa magulu. Iwo amatha kusiyanitsa magawo angapo:

1. presynthetic nyengo - selo chikamakula, amasonkhana mapuloteni ndi chakudya, ndi mwachangu apanga ATP (adenosine triphosphate).

2. Kupanga nthawi - zakuthupi majini ndi kawiri.

3. postsynthetic nyengo - zinthu ma ndi kawiri, pali mapulotini amapanga kulekanitsa spindle.

Magawo mitosis

Gulu la phata la maselo eukaryotic - ndondomeko chimene chili chofunika mapangidwe organelles zina - centrosomes. Malowa ali pamtunda pafupi phata, ndipo ntchito yake yaikulu ndi kupanga organelles watsopano - spindle. Kapangidwe zimathandiza wogawana kugawa DNA pakati pa maselo mwana wamkazi.

Pali magawo anayi a mitosis:

1. Prophase: chromatin mu phata la kumaundanitsa mu chromatids, amene ali pafupi centromeres akupita awiriawiri kupanga DNA. Nucleoli kupasuka, kumwazikana kwa mitengo yonyamulira ya centrioles cha ndende. Anapanga magawano spindle.

2. Metaphase: DNA ndi anakonza mu mzere adapyola pakati pa foni kupanga mbale metaphase.

3. Anaphase: chromatids mogwirizana kuchokera pakati selo kwa mizati, kenako ogaŵikana awiri centromere. gulu limeneli ndi zotheka chifukwa cha magawano spindle, ulusi umene ndi kuchepetsedwa ndipo anatambasula DNA madera osiyana.

4. Telophase: anapanga mwana mtima. Chromatids kachiwiri kuwasandutsa chromatin, phata la aumbike, ndipo mmenemo - ndi nucleoli. Malekezero onse gulu la cytoplasm ndi mpanda selo mapangidwe.

endomitosis

Kuwonjezeka zinthu chibadwa, omwe sasamalira gulu la phata anacemerwa endomitosis. Umapezeka maselo a nyama ndi zomera. Pankhaniyi palibe chiwonongeko cha cytoplasm ndi phata Kakhungu, koma amakhala chromatin mu DNA, kenako dispiralized.

Zimenezi zimathandiza kupeza polyploid phata kumene zili DNA ndi kuchuluka. Chotero njuchi kupanga maselo opezeka mafupa. Komanso, pali milandu, pamene DNA ndi kawiri, ndipo topangira DNA akanali yemweyo. Amadziwika monga pulasitiki, ndi angapezeke maselo tizilombo.

kutanthauza mitosis

Mitotic gulu la phata la - ndi njira kukhalabe akonzedwa zonse DNA. maselo mwana wamkazi ndi kuika yomweyo imene imachititsa monga kholo ndi onse a makhalidwe chofuna kuchita izo. Mitosis chofunika kuti:

- kukula ndi chitukuko cha tizilombo multicellular (kuchokera maphatikizidwe maselo nyongolosi);

- kusamutsidwa kwa zigawo selo m'munsi pa pamwamba ndi m'malo maselo magazi (erythrocytes, leukocytes, maselo othandiza magazi kuundana);

- kukonza kuonongeka minofu (ena nyama luso kubadwanso chofunika kupulumuka, monga starfish ndi abuluzi);

- asexual kubalana zomera ndi nyama zina (invertebrates).

meiosis

nagawira nyongolosi maselo limagwirira mtima kumasiyana penapake kuchokera somatic. Chifukwa cha zimenezi, iye analandira maselo ndi theka mfundo majini kuposa akapolo anzawo akale. Izi ndi zofunika kuti asunge nambala zonse DNA m'selo iliyonse la thupi.

Meiosis amapezeka mu mbali ziwiri:

- Kuchepetsa siteji;

- equational siteji.

Yoyenera pa ndondomeko n'chotheka maselo ndi ngakhale chiwerengero DNA (diploid, tetraploid, ndi geksaproidnym T. D.). Kumene, ikhala zotheka pochitika meiosis ndi maselo ndi osamvetseka ya DNA, koma ndiye ana akhoza kukhala yotheka.

limagwirira Izi zipangitsa sterility mabanja interspecific. Kuyambira mu nyongolosi maselo akadamsana osiyana DNA, izo complicates maphatikizidwe zawo ndi maonekedwe a mbewu yotheka ndi yachonde.

Wa gulu loyamba meiosis

gawo akubwereza dzina la anthu mitosis: prophase, metaphase, anaphase, telophase. Koma pali kusiyana kwambiri.

1. Prophase: iwiri ya DNA zimapangitsa angapo kusinthika, kudutsa magawo asanu (leptotena, zygotes, Paquita, diplotene, diakinesis). Pali zikomo izi zonse kwa conjugation komanso kuwoloka-bwereza.

Conjugation - ichi mgwirizano DNA magazi. Mu leptotene therebetween kupanga filaments woonda kenako nawo khromozomu awiriawiri zygotene ndi zotsatira akamagwira kapangidwe ka chromatids anayi.

Kusinthanitsidwa - ndondomeko ya mtanda zigawo angalole pakati chromatids mlongo kapena DNA magazi. Izi zimachitika pa siteji pachytene. polumikizana anapanga (chiasm) DNA. Anthu, kuphana awa akhoza kukhala pakati sate-faifi kwa sikisite-sikisi. The chifukwa cha ndondomekoyi ndi heterogeneity majini a chifukwa chuma, kapena masiyanidwe gametes.

Pamene mukubwera siteji diplotene wa chromatids anayi maofesi anawonongedwa ndi mlongo DNA vzaimoottalkivayutsya. Diakinesis anamaliza kusintha kwa prophase kuti metaphase.

2. Metaphase: DNA munzere pafupi ndi equator ya chipindacho.

3. Anaphase: DNA, komabe ongokhala chromatids awiri mogwirizana ndi mizati ya chipindacho.

4. Telophase: kugawa spindle zikadzawonongedwa, chifukwa mu mapangidwe maselo awiri ndi akonzedwa haploid DNA ndi kawiri kuchuluka kwa DNA.

The chachiwiri meiotic magawano

ndondomeko umenewu umatchedwanso "mitosis, meiosis." Mu mphindi pakati pa magawo awiri DNA mwendo zimachokeradi, ndi selo chachiwiri akulowa prophase wa akonzedwa chomwecho DNA, imene anatsalira 1 telophase.

1. Prophase: DNA condense mipita pakati kulekana maselo (zotsala ake amasiyana mitengo yonyamulira ya selo), ndi m'chimake n'kugwa phata anapanga magawano spindle oyenerera perpendicular kwa spindle wa gulu loyamba.

2. Metaphase: DNA ili pa equator, aumbike metaphase mbale.

3. Anaphase: DNA anawagawa chromatids kuti amawala mu njira zonse.

4. Telophase: maselo mwana anapanga chromatids pakati dispiralized mu chromatin.

Kumapeto kwa gawo lachiwiri la selo kholo limodzi, tili bulanchi anayi ndi theka ingachititse DNA. Ngati meiosis chikuchitika molumikizana ndi mzere nyongolosi (kutanthauza mapangidwe maselo kugonana), magawano ndi zikuchepa m'goli ndi aumbike mwa selo limodzi ndi akonzedwa haploid DNA ndi atatu kuchepetsa ng'ombe, osati onyamula kofunika kudziwa chibadwa. Iwo pofuna kuti dzira ndi umuna anakhalabe theka la chuma cha majini a khungu kholo. Komanso, fomu iyi ya kugawikana nyukiliya amapereka maonekedwe a ma yatsopano imene imachititsa, komanso cholowa koyera alleles.

Mu Baibulo losavuta wa meiosis alipo pamene pali mtanda umodzi okha mu gawo loyamba ndi lachiwiri pali kusinthanitsidwa. Asayansi amati fomu iyi ndi kalambulabwalo zinachokera ochiritsira meiosis zamoyo multicellular. Mwina pali njira zina fission nyukiliya, amene asayansi simumamudziwa.