Haihuwa aiki da kuma akanta na meiosis

A haihuwa aiki na jiki ne da za'ayi a lokacin gamuwa na biyu gametes (jam sel) a cikin taron da m ci gaban da zygote na biyu jiki - kwan da ya hadu. A jima'i iyayentaka Kwayoyin suna da wani sa na n-chromosomes. Ya kira haploid. Zygote yana shan wani sa na wadannan, shi ne wani diploid cell, watau, chromosome yawan 2n akwai: daya masu juna biyu da kuma daya uba. Halittu meiotic rabo musamman muhimmancin kamar yadda a kan salula kunshi a gaskiyar cewa godiya ga shi, da haploid cell kafa daga diploid Kwayoyin.

definition

Meiosis a ilmin halitta da aka kira wani irin mitosis. saboda ta diploid somatic sel da al'aura gland kasu kashi 1n gametes. Lokacin da kwaya hadu, akwai wani Fusion na gametes. Saboda haka, shi yana murmurewa 2n chromosome sa. Meaning of meiosis ne don tabbatar da adana daga cikin muhimmi kowane irin rayayyun kwayoyin halitta chromosomes da ya dace yawa na DNA.

description

Meiosis - da tsari ne m. Ya kunshi iri biyu rarraba jẽre wadannan juna: meiosis na da meiosis II. Kowace daga cikin matakai, bi da bi, ya kunshi prophase, metaphase, anaphase, telophase. A farko rabo daga meiosis ko meiosis I, halves da yawan chromosomes, Ina nufin akwai sabon abu daga cikin abin da ake kira akan rage division. Lokacin shi ne mataki na biyu na meiosis ko meiosis II, haploid Kwayoyin ba barazana ga canji, shi ne ceto. Wannan tsari shine ake kira equational division.

Duk da Kwayoyin a mataki na meiosis, kawo wasu bayanai a kan kwayoyin matakin.

• Meiotic prophase na farko - mataki m Helix chromatin da kuma samuwar chromosomes. A karshen wannan sosai hadaddun mataki da kwayoyin abu ba a cikin asalin siffan - 2n2 chromosomes.
• Metaphase zo - zo da matsakaicin matakin na Helix. A kayyade abu ne har yanzu ba su canja ba.
• Anaphase na meiosis ne tare da wani raguwa. Kowane biyu daga iyayentaka chromosomes ba ɗaya daga cikin 'yar Kwayoyin. Halitta abu ne canza a abun da ke ciki, kamar yadda chromosome lambar da aka rabin cewa: domin kowane iyakacin duniya na cell wajibi ne ga 1n2 chromosome.
• Telophase - lokaci a lokacin da kafa da zuciyar, rabu cytoplasm. 'Yar Kwayoyin suna halitta, su ne 2 da kowane biyu chromatids. watau kafa na chromosomes a haploid su.
• Bugu da ari interkinesis lura, a takaice hutu tsakanin farko da na biyu mataki na meiosis. The biyu ya Kwayoyin suna shirye su shiga cikin mataki na biyu na meiosis, wanda ya auku da wannan ginshiki a matsayin cewa na mitosis.

A akanta na meiosis ne saboda haka a gaskiyar cewa a cikin mataki na biyu da hadaddun sunadaran riga ya kafa haploid Kwayoyin 4 - 1n1 chromosomes. Watau, daya diploid uwa cell rãyar hudu - kowane haploid chromosome sa. A daya daga cikin na farko meiotic digiri lokaci kayyade kayan recombines, da kuma na biyu mataki ne da za'ayi motsi chromosomes da chromatids zuwa daban-daban sandunan da tantanin halitta. Wadannan gwagwarmayoyi - tushen bambancin da daban-daban haduwa da intraspecific.

sakamakon

Saboda haka, akanta na meiosis, gaske mai girma. Da farko, ya kamata a lura a matsayin babban, babban mataki na Farawa na gametes. Meiosis an tabbatar canja wuri da kwayoyin bayanai daga daya kwayoyin nau'in zuwa wani, idan har cewa suka haifa jima'i da. Meiosis sa intraspecific haduwa faruwa saboda ya Kwayoyin bambanta ba kawai daga iyaye amma kuma suka sãɓã wa jũna.

Bugu da kari, nazarin halittu muhimmancin meiosis kunshi a samar da rage yawan chromosomes a daidai lokacin da jam sel suna kafa. Meiosis tabbatar da haploid. a lokacin da hadi da zygote diploid chromosome tsarin da aka mayar.