Meiosis: Te Tukanga me tōna Hiranga i te Ora
Ko te Meiosis he momo wehenga pūtau e whai wāhi nui ana ki te whakaputa uri ā-ira me te kanorau ira. Mā tēnei tukanga, ka puta mai i ngā pūtau ira takirua ngā pūtau haploid—ngā pūtau ira i roto i ngā kararehe me ngā pūmua i roto i ngā tipu. Ehara i te mea he mea nui te Meiosis mō te hanganga o ngā pūtau ira anake, engari mō te whakarite hoki i te rerekētanga ira i waenga i ngā uri. Ka matapakihia e tēnei tuhinga te tukanga taipitopito o te meiosis, ngā wāhanga e whai wāhi ana, me tōna hiranga i roto i te koiora.
Te Mārama ki ngā Kaupapa Taketake o te Meiosis
He rerekē te Meiosis i te mitosis, arā, he wehenga pūtau noa e puta ai ngā pūtau tamāhine ōrite. I roto i te meiosis, ka wehea e te pūtau kotahi ngā pūtau e rua hei whakaputa i ngā pūtau tamāhine e whā, ia pūtau he haurua te maha o ngā ira o te pūtau matua. E rua ngā wāhanga matua o te Meiosis: Meiosis I me Meiosis II. Ka wehea anō ia wāhanga ki ētahi wāhanga: prophase, metaphase, anaphase, me te telophase.
Ngā Wāhanga o te Meiosis
Meiosis I
– Porowhita I: Koinei te wāhanga roa rawa atu, tino uaua hoki o te meiosis. I te porowhita I, ka honoa ngā ira-ira ōrite i roto i te tukanga e kiia nei ko te synapsis. E rua ngā ira-ira ōrite kei roto i ia takirua ōrite, ka hanga he hanganga e kiia nei ko te tetrad. Koinei te wāhi e puta ai te whakawhiti i ngā wāhanga ira-ira i waenga i ngā ira-ira ehara i te tuahine, e mōhiotia ana ko te whakakotahitanga, te whakawhiti rānei. He mea nui tēnei whakakotahitanga mō te whakanui ake i te rerekētanga ira.
– Wāhanga-ā-ira I: I te wāhanga-ā-ira I, ka whakarārangihia ngā takirua ira-ira ōrite i te pereti wāhanga-ā-ira. He tūpono tēnei whakarārangi, ā, ka whai wāhi atu ki te rerekētanga ira mā te wehewehe motuhake.
– Anaphase I: I te anaphase I, ka piri ngā microtubules ki ngā kinetochores ka kukume i ngā chromosomes ōrite ki ngā pou rerekē o te pūtau. Kāore i rite ki te mitosis, kāore ngā chromatids tuahine e wehea, nō reira kotahi anake te chromosomes e whiwhihia ana e ia pou mai i ia takirua ōrite.
– Telophase I me te Cytokinesis: Ka tae ngā irakōmona ki ngā pou rerekē, ka puta te cytokinesis, ka puta ai ngā pūtau tamāhine e rua he rerekē te ira, he haploid hoki, ahakoa e rua ngā chromatids o ia irakōmona.
Meiosis II
He rite te Meiosis II ki te mitosis, arā, ka wehea ngā chromatids tuahine.
– Porowhita Tuarua: Kāore i rite ki te Porowhita Tuatahi, kāore he hononga honohono, he whakawhiti rānei. Ka hurihia te taputapu porowhita, ā, ka neke ngā ira ki te pereti porowhita.
– Wāhanga-ā-ira II: Ka tū ngā ira-ira ki runga i te pereti wāhanga-ā-ira. E rua ngā ira-ira kei roto i ia ira-ira e rite ana ki te wehe.
– Anaphase II: I tēnei wā, ka wehea ngā kinetochores o ngā chromatids tuahine, ā, ka kumea ki ngā pou rerekē e ngā microtubules.
– Telophase II me te Cytokinesis: Ka hurihia te kiriuhi karihi huri noa i ia huinga chromosomes, ā, muri iho ka cytokinesis, ka wehea te pūtau kia rua. Ko te mutunga iho he whā ngā pūtau haploid ahurei ira.
Te Hiranga o te Meiosis
He mea tino nui te mahi a te meiosis i roto i te koiora, ā, kua rangahaua whānuitia nā tōna pānga nui ki te ora.
1. Te Kanorau Ira: Ko tētahi o ngā hua matua o te meiosis ko te whakaputanga o ngā gametes me ngā hanganga ira rerekē. Mā ngā tukanga whakawhiti me te wehewehe motuhake e puta ana i te wā meiosis ka whakarite kia noho ia gametes hei huinga ahurei o ngā rauemi ira o ngā mātua.
2. Te Urutau me te Whanaketanga: Ko te rerekētanga ira e hua mai ana i te meiosis te rauemi mata mō te kōwhiringa taiao. Tērā pea he painga urutau motuhake ā ngā momo takitahi e āhei ai rātou ki te ora me te whakaputa uri, ā, koinei te pūtake o te whanaketanga o te momo.
3. Te Pupuri i te Pūmautanga o te Ira Tangata: Mā te Meiosis ka whakaitihia te maha o ngā ira tangata kia hoki mai ai te maha o ngā ira tangata takirua i te wā e whakatōngia ai. Ki te kore tēnei whakaitinga, ka rua te maha o ngā ira tangata i ia whakatipuranga hou, ā, ka kore e pumau, ka kino hoki.
4. Ngā Hē o te Meiotic me ngā Mate Ira: Ka taea e ngā hapa i roto i te meiosis te whakaputa i ngā hē o te ira pērā i te trisomy, te monosomy, me ētahi atu hē hanganga. Ko tētahi tauira o te mate ira i puta mai i ngā hē o te meiotic ko te Down syndrome, i puta mai i te trisomy o te ira 21.
Whakamutunga
He tukanga wehewehe pūtau nui te meiosis i roto i ngā rauropi whakaputa uri ā-ira. Mā te whakaputa i ngā gametes haploid, ā-ira motuhake, he mea nui te meiosis i roto i te kanorau koiora me te whanaketanga. Ahakoa he uaua, ka mahi tonu te tikanga o te meiosis ki te pupuri i te pumau ira me te whakarato i ngā rerekētanga he mea nui ki te urutau me te oranga o ngā momo. Nō reira, he mea nui te mārama ki te meiosis ki te ako i te koiora hou me te ira, e whakarato ana i ngā māramatanga whai hua ki te whanaketanga me te urutau o te ora i roto i te wā.
