Ta yaya ne nukiliya fission? fission Iri

Kowane cell fara ta rai a lokacin da rabu da iyaye, kuma ya ƙare har kasancewa, ba da damar bayyana wa 'yar Kwayoyin. Nature bayar da fiye da daya hanya rarraba core, dangane da tsarin.

Hanyoyin da cell division

Rarraba core dogara a kan tantanin halitta irin :

- binary fission (samu a prokaryotes).

- amitosis (kai tsaye hanyar division).

- Mitosis (kowa a eukaryotes).

- Meiosis (ga rarraba jam sel).

fission iri suna ƙaddara da yanayi da kuma daidai da tsarin da cell da kuma aiki da shi ya yi aikin a cikin macroorganism ko ta kanta.

binary fission

Mafi sau da yawa irin wannan da aka samu a prokaryotic Kwayoyin. Ya kunshi a maimaita madauwari jigidar halittar DNA. Binary fission na tsakiya ne don haka ya kira saboda uwar cell akwai biyu daidai sized 'yar.

Bayan kwayoyin al'amari (DNA ko RNA kwayoyin) an shirya daidai da, Ina nufin shi ninki biyu, daga cell bango fara da nunawa da mai gangara bangare, wanda aka hankali Tapered kuma cytoplasm raba zuwa biyu kamar daidai sassa.

Na biyu rarraban aiwatar kira budding ko m binary fission. A wannan yanayin, da cell ganuwar bayyana protrusion rabo, wanda aka hankali girma. Bayan da "kodan" da kuma girman da uwar cell zai zama daidai, sai su rabu. A sashi na cell bango aka hada sake.

amitosis

Wannan rabo daga cikin tsakiya kama da wadanda aka bayyana a sama, tare da bambanci da cewa babu wani maimaitawan wannan kayyade abu. Wannan hanya da aka farko aka bayyana da Remak halitta. Wannan abu ya faru a pathologically canza sel (m canji), kuma shi ne mai physiological na kullum ga hanta nama, guringuntsi, kuma cornea.

A tsari shine ake kira nukiliya fission amitosis saboda cell rike ta aiki, da kuma ba ya rasa su kamar yadda a lokacin mitosis. Wannan bayyana mahaukaci Properties hade da cell division tsari. Bugu da kari, kai tsaye division core wuce ba tare da dogara sanda, saboda haka 'yar Kwayoyin chromatin ne rarraba uniformly. A cikin wadannan, irin Kwayoyin ba zai iya yin amfani da da mitotic sake zagayowar. Wani lokaci, a sakamakon amitosis kafa multinucleated Kwayoyin.

mitosis

Wannan tsaye ba makaman nukiliya fission. Mafi sau da yawa samu a eukaryotic Kwayoyin. Babban bambancin da wannan tsari ya ta'allaka ne da cewa yaro da kuma masu juna biyu Kwayoyin dauke da wannan adadin chromosomes. Ta hanyar wannan jiki yana goyan bayan da ake bukata yawan Kwayoyin, kazalika zai yiwu farfadowa da kuma ci gaban tafiyar matakai. A farko mitosis a wata dabba cell bayyana Flemming.

A tsari na rarraba tsakiya a wannan harka da aka raba kai tsaye a kan Interphase da mitosis. Interphase - a jihar da Kwayoyin huta tsakanin ƙungiyoyin. Yana iya bambanta da dama bulan:

1. presynthetic lokaci - cell tsiro, shi accumulates sunadaran da carbohydrates, an rayayye hada ATP (adenosine triphosphate).

2. Roba lokaci - da kwayoyin abu ne ninki biyu.

3. postsynthetic lokaci - salula abubuwa suna ninki biyu, akwai sunadaran da cewa yin up rarraban dogara sanda.

Da kasoshin lokatan mitosis

Da rabo daga cikin nucleus din eukaryotic Kwayoyin - wani tsari wanda wajibi ne ga samuwar wani ƙarin wasu gabbansa - centrosomes. An located kusa da tsakiya, da kuma ta babban aiki ne ta samar da sabon wasu gabbansa - dogara sanda. Wannan tsarin taimaka wajen ko'ina raba chromosomes tsakanin 'yar Kwayoyin.

Akwai hudu bulan na mitosis:

1. Prophase: chromatin a cikin nucleus din condenses a cikin chromatids, wanda suke kusa da centromeres suna faruwa a cikin nau'i-nau'i ta samar da chromosomes. Nucleoli narke, Sai ku wãtsu a cikin dogayen sanda na cell centrioles. Kafa division dogara sanda.

2. Metaphase: da chromosomes ana shirya a wani layi wucewa ta cikin cibiyar na cell samar da metaphase farantin.

3. Anaphase: chromatids diverge daga cell cibiyar zuwa ga dogayen sanda, sa'an nan ya kasu kashi biyu centromere. Wannan yunkuri shi ne zai yiwu saboda division dogara sanda, da zaren wanda aka rage, kuma miƙa chromosomes a daban-daban kwatance.

4. Telophase: kafa ya nuclei. Chromatids sake juya cikin chromatin, da tsakiya da aka kafa, da kuma a cikin shi - da nucleoli. Ƙare duka rabo daga cikin cytoplasm da cell bango samuwar.

endomitosis

A karuwa a cikin kwayoyin abu, wanda ba ya samar wa rabo daga cikin tsakiya, da ake kira endomitosis. An samu a cikin sel na shuke-shuke da dabbobi. A wannan yanayin babu wani halakar da cytoplasm da tsakiya membrane, amma zama chromatin cikin chromosomes, sa'an nan dispiralized.

Wannan tsari damar zuwa samu polyploid tsakiya inda DNA abun ciki da aka ƙara. Irin mallaka kafa Kwayoyin samu a bargo. Bugu da kari, akwai lokuta, lokacin da cikin jigidar halittar DNA da aka ninki biyu, da kuma yawan chromosomes kasance iri guda. Suna da aka sani da polythene, kuma suka za a iya samu a kwari Kwayoyin.

Ma'ana mitosis

Mitotic rabo daga cikin tsakiya - shi ne mai hanya don kula da akai sa na chromosomes. 'Yar Kwayoyin suna da wannan sa kwayoyin halitta a matsayin iyaye, kuma duk da halaye muhimmi zuwa gare shi. Mitosis ake bukata domin:

- girma da kuma ci gaban da kwayar kwayoyin (daga Fusion na jam sel).

- hijirar na ƙananan cell yadudduka a saman da kuma maye jini Kwayoyin (erythrocytes, leukocytes, platelets).

- gyara lalace nama (a cikin wasu dabbobi da damar domin farfadowa ne kafin rayuwa, kamar tarwada da kuma kadangaru).

- sake yiwuwar tohowarsu, na shuke-shuke da kuma wasu dabbobi (kwaro).

meiosis

rarraba jam sel nuclei inji bambanta da ɗan daga somatic. A sakamakon haka, ya samu Kwayoyin cewa da rabin kwayoyin bayanai fiye da waɗanda suke a gabãninsu. Wannan shi ne zama dole domin ya kula da akai yawan chromosomes a kowane cell na jiki.

Meiosis auku a matakai biyu:

- rage mataki.

- equational mataki.

Proper lokacin tsari da mai yiwuwa ne kawai a sel tare da wani ko da yawan chromosomes (diploid, tetraploid, kuma geksaproidnym t. D.). Hakika, za ta zauna ita yiwu auku meiosis da Kwayoyin tare da m sa na chromosomes, amma sai da zũriyarsu, bazai mai yiwuwa.

Wannan inji tabbatar sterility a interspecific aure. Tun a cikin jam sel ne daban-daban sets na chromosomes, shi dagula su fe da kuma bayyanar mai yiwuwa da kuma m zuriyarsa.

A farko rabo daga meiosis

lokaci ya mayar da sunan waɗanda suke a cikin mitosis: prophase, metaphase, anaphase, telophase. Amma akwai wasu gagarumin bambance-bambance.

1. Prophase: biyu kafa chromosomes sa jerin canje, wucewa ta hanyar biyar, saukarwa (leptotena, zygotes, Paquita, diplotene, diakinesis). Akwai duk wannan godiya ga Tasrifu da mararraba-kan.

Tasrifu - wannan haduwa na homologue chromosomes. A leptotene therebetween samar da bakin ciki filaments sa'an nan ta shiga a zygotene chromosome nau'i-nau'i da kuma sakamakon samu ta hanyar tsarin hudu chromatids.

Crossover - aiwatar da giciye-sassan na musayar tsakanin 'yar'uwar chromatids ko homologue chromosomes. Wannan na faruwa a pachytene mataki. Kafa intersections (chiasm) chromosomes. A cikin mutane, wadannan mu'amala iya zama tsakanin talatin da biyar zuwa sittin da shida. A sakamakon wannan tsari ne da kwayoyin heterogeneity na da sakamakon abu, ko canzawa gametes.

Lokacin da ya je wani mataki diplotene na hudu chromatids gidaje suna hallaka 'yar'uwar chromosomes vzaimoottalkivayutsya. Diakinesis kammala mika mulki daga prophase zuwa metaphase.

2. Metaphase: chromosomes tsaye kusa da ekweita na cell.

3. Anaphase: chromosomes, har yanzu kunsha na biyu chromatids diverge da sandunan da tantanin halitta.

4. Telophase: rarraba dogara sanda ne ya hallaka, sakamakon samuwar biyu Kwayoyin tare da wani haploid sa na chromosomes da ciwon sau biyu da adadin DNA.

Na biyu meiotic division

Wannan tsari ne da kuma ake kira "mitosis, meiosis." A lokacin tsakanin biyu bulan DNA kwafi ba ya faruwa, da kuma na biyu cell shiga prophase na wannan sa na chromosomes, wanda ta zauna bayan 1 telophase.

1. Prophase: chromosomes cunkoso kafa rabuwa cell cibiyar (ta saurã sãɓã wa jũna sandunan na cell), da kuma daina kai hare hare fadi tsakiya kafa division dogara sanda zubar perpendicular zuwa dogara sanda na farko division.

2. Metaphase: chromosomes suna located a ekweita, an kafa metaphase farantin.

3. Anaphase: chromosomes kasu kashi chromatids cewa haskaka a duk inda.

4. Telophase: a 'yar Kwayoyin kafa cibiya chromatids dispiralized cikin chromatin.

A karshen na biyu lokaci guda iyaye cell, muna da hudu rassa da rabin sa na chromosomes. Idan meiosis faruwa a tare da tare da jam line (cewa shi ne, da samuwar jima'i Kwayoyin), da rabo ne sharply m, kuma an kafa ta a guda cell da haploid sa na chromosomes da uku rage maraƙi, ba ɗauke da zama dole kayyade bayani. Su zama dole don tabbatar da cewa a kwai kuma maniyyi ya zauna kawai rabin na kayyade abu na iyaye cell. Bugu da ƙari, wannan nau'i na nukiliya division samar da bayyanar sabon haduwa da kwayoyin halittu, kazalika da tsarki gādon alleles.

A cikin sauki version of meiosis akwai lokacin da babu daya ne kawai mashaya a farkon lokaci, kuma a karo na biyu akwai crossover. Masana kimiyya bayar da shawarar cewa wannan nau'i ne juyin precursor na al'ada meiosis kwayar kwayoyin. Zai yiwu akwai wasu hanyoyi na nukiliya fission, wanda masana kimiyya sani ba.