Cell division: da bayanin ainihin matakai

Cell division - shi ne halitta aiwatar da damar ga al'ada girma, ci gaba da kuma haifuwa da kwayoyin. Wannan qara yawan Kwayoyin aka kwashe nama girma, jima'i haifuwa da kuma watsa daga cikin hereditary abu. The main iri cell division - a meiosis da mitosis. Kowace daga cikin wadannan matakai yana da wasu peculiarities.

mitosis

Mitosis - a cell division, yana yiwuwa daga masu juna biyu Kwayoyin wadda aka kafa da biyu ya chromosomes da m lamba domin. Irin wannan matakai ko da yaushe ya auku tare da somatic Kwayoyin na kwayoyin, samar da girma, ci gaba da farfadowa daga kyallen takarda da kuma gabobin.

A rayuwa ta sake zagayowar daga Kwayoyin za a iya raba Interphase da mitosis. Interphase - don haka ya kira a kwantar da hankula mataki, a lokacin da akwai aiki kira da kuma jari na abubuwa wajibi ne ga cell division. Zuwa ga farkon mitosis faruwa anya yawan chromosomes.

Mitosis mafi yawa ana zuwa kashi hudu main saukarwa.

• Prophase. A wannan lokacin za ka lura da farkon na chromosome sandaro. Biyu m chromosomes ake juna daya centromere. A farkon akwai wani rabo prophase da centrioles. Yanzu biyu ya centrioles fara sannu a hankali watsa zuwa biyu daura da cell. Duk da haka, da suka saura a daure da bakin ciki gina jiki filaments - don haka kafa division dogara sanda. By karshen wannan mataki, chromosomes rage da kuma zama yawa thicker da kuma motsa zuwa ga ekweita na cell.
• Metaphase - sosai short mataki, wanda ta fara da jeri na chromosomes a ekweita na cell. Kusan lokaci guda, a lokaci guda a duk chromosomes ne da rabo daga cikin centromere.
• Anaphase - thread dogara sanda saka a cikin centromere na chromosome. A wannan lokacin da yaro chromosome ne sannu a hankali motsi zuwa daura sanduna. An yi imani da cewa thread dogara sanda ba kawai directed chromosomes, amma kuma saboda da gaban ATP da aka rage, accelerating su bambanta rarrabuwar.
• Telophase - fara a daidai lokacin da chromosomes ya tafi da sanduna. Su unwind da kuma zama ƙasa da m - sama da Allaha jihar. Around gungu na chromatin ne a kira na wani sabon nukiliya ambulan. A layi daya da cell division auku - cytoplasm da wasu gabbansa raba daidai tsakanin 'yar tsarin.

meiosis

Meiosis - wannan tsari na cell division, a lokacin da hudu gametes kafa tare da wani tsari guda da chromosomes. Irin wannan tafiyar matakai faruwa a lokacin samuwar gametes - spermatozoids, ovules (shuka don haka da cewa samuwar spores). Irin wannan matakai samar for musayar kayyade abu da kuma combinatorial canzawa. Lokacin da biyu gametes, kowanne daga abin da ya ƙunshi kawai rabin na kayyade abu, da yawan chromosomes an rage, amma su bi da bi ne ya canja.

Kan aiwatar da kafa gametes kunshi biyu short meiotic rarrabuwa, a kowanne daga abin da duk na sama matakai za a iya bambanta. Amma tsakanin Ƙungiyarku biyu na Interphase ba bayyana, kuma DNA kira faruwa. Sanadiyar haka ne, na biyu ya shiga prophase na biyu Kwayoyin tare da wani tsari guda da chromosomes (a cikin mutane shi ne 46). A sakamakon na biyu division - mai 4 gametes wanda da 23 chromosomes.

amitosis

Amitosis - shi ne uncharacteristic cell division, wanda ya auku da wuya. Lokacin da wannan cell rike duk physiological ayyuka. A wannan tsari, akwai wani kwafi na kayyade abu da kuma cell division. Divisible kawai kwaya, amma ba tare da kafa wani mitotic dogara sanda. A sakamakon wannan tsari, chromosomes bambanta a bazuwar domin - kafa Multi-nucleate cell. Ya kamata a lura cewa amitosis yakan auku a tsufa da kuma mutuwa ko Kwayoyin, ko a pathologically sauya Tsarin (neoplastic Kwayoyin).