Te Hanganga o te Ira-ira i roto i te Pūtake Eukaryotic
He hanganga matatini ngā ira-kōmona kei roto i te pūtake o ngā pūtau eukaryotic. He mahi nui tā rātou ki te rokiroki, ki te tāruarua, me te whakapuaki i ngā mōhiohio ira. I roto i tēnei tuhinga, ka tūhuratia e mātou te hanganga o ngā ira-kōmona eukaryotic, me te mārama ki ō rātou wāhanga taketake, ngā tikanga whakahaere, me tō rātou hiranga i roto i te horopaki o te koiora pūtau me te koiora ngota.
Kupu Whakataki: He aha te Chromosome?
He hanganga āhua tokotoko ngā ira-kōpura e titoa ana i te DNA me ngā pūmua. I roto i ngā pūtau eukaryotic, kei roto ngā ira-kōpura i te karihi. Hei tauira, kei roto i te pūtau tangata he 46 ngā ira-kōpura, arā, e 23 ngā takirua ira-kōpura ōrite.
Hanganga Taketake o ngā Chromosome
1. DNA: Ko te huānga tino taketake o te ira-kōromo ko te DNA (waikawa deoxyribonucleic). He ngota pūmua roa te DNA e pupuri ana i ngā mōhiohio ira. Ka takaihia, ka pēhia ia ngota ira-kōromo i roto i te ira-kōromo kia hanga he āhua kiato ake mā te āwhina o ngā pūmua.
2. Ngā Histone: Ko ngā pūmua histone he pūmua whakawhāiti hanganga e whai wāhi nui ana ki te whakarite i te DNA. Ka takai te DNA ki ngā aho histone, ka hanga i ngā hanganga e kiia nei ko ngā nucleosome. Ko te nucleosome he tata ki te 147 ngā takirua turanga o te DNA e takai ana ki te matua o ngā pūmua histone e waru (he octamer histone).
3. Chromatin: Ko te huinga o te DNA me ngā pūmua histone e kiia ana ko te chromatin. E rua ngā āhua o te chromatin:
– Euchromatin: He wāhi wetekina ake, e kaha ana ki te whakaputa kupu, e āhei ai ngā whākōkī whakaputa kupu me ētahi atu āhuatanga ki te uru atu ki te DNA.
– Heterochromatin: He wāhi kiato ake, he iti ake te kaha o te whakawhitiwhiti kōrero, he rite ki ngā ira kāore e hiahiatia ana e te pūtau i ētahi wā.
Kete Ira-Ira: Mai i te DNA ki ngā Ira-Ira
Me whakapoto te DNA eukaryotic roa kia uru ki roto i te karihi pūtau iti. He maha ngā taumata whakaritenga o tēnei tukanga:
1. Ngā irahiko: Ko te taumata tuatahi o te whakaritenga i whakahuatia i mua ake nei. Ka āwhina ngā irahiko ki te whakaiti i te roa o te DNA e uru atu ana mā te takai i roto i ngā matūriki rite ki te pītiti.
2. Ngā muka 30 nm: Ka whakapikohia anō ngā nucleosomes ki roto i ngā muka chromatin he tata ki te 30 nm te whānui. Mā tēnei ka nui ake te whakakīkī mō te DNA, ā, ka taea te whakapūpū ake i ētahi wā, pērā i te wā e wehea ana te pūtau.
3. Ngā Rohe Porowhita: Ka takaihia ēnei muka 30 nm ki roto i ngā porowhita e herea ana ki te tuara pūmua, ka hanga he hanganga kiato ake. Ka taea te whakarite anō i ēnei porowhita ki ngā hanganga taumata-teitei.
4. Te Whakapūtanga o te Ira Tangata: I te wā o te mitosis, te meiosis rānei o te wehenga pūtau, ka piki haere te whakapūtanga o ngā ira tangata kia kitea rā anō i raro i te karu hiko mārama. Koinei te taumata teitei rawa o te whakapūtanga, e whakarite ana i te tohatoha tika o ngā mōhiohio ira ki ngā pūtau tamāhine.
Te Tūranga Mahi me te Hiranga o te Hanganga o te Ira Tangata
1. Te Whakatakotoranga DNA: Mā te hanganga o ngā ira-kōromō ka taea te whakatikatika tika me te whai hua o te ira-kōromō i mua i te wehenga pūtau. Ka tāruatia ia ira-kōromō kia whiwhi ai ia pūtau tamahine i tētahi huinga ira-kōromō katoa.
2. Te tuhi ira: Mā te noho mai o te euchromatin wetekina ka taea te whakaputa i ngā ira e tika ana mō te mahi a te pūtau, ko te whakaritenga heterochromatin ka pupuri i ngā ira kia kore e mahi i raro i ētahi āhuatanga.
3. Te Tohatoha Ira i te Wā Wehenga: Mā te whakakotahitanga o ngā ira i te wā o te mitosis me te meiosis ka whiwhi ia pūtau i tētahi huinga katoa o ngā ira, he mea nui mō te tipu, te whakaputa uri, me te whakatika kiko.
4. Te Whakahaere Ira: Ka pā te āhua o te tākai o te DNA i roto i ngā nucleosome ki te kaha o ngā ira ki te whakaputa. Ka taea e ngā whakarerekētanga matū ki ngā histones me te DNA, pērā i te methylation me te acetylation, te whakarerekē i te urunga atu ki ngā rohe DNA motuhake, ā, he tikanga nui tēnei mō te whakahaere ira.
Te Hanganga me te Mate o te Ira Tangata
Ka taea e ngā mate ira te puta mai i ngā mate ira i ngā mate o te hanganga, o te maha rānei o ngā ira. Ko ētahi o ngā mate e mōhiotia whānuitia ana ko:
1. Te Mate Down: I puta mai i tētahi tārua tāpiri o te ira 21 (trisomy 21).
2. Matepukupuku: Ka taea e ngā panonitanga o te hanganga o ngā ira, pērā i te whakawhiti ira, te whakanui rānei i ngā ira, te whakahohe i ngā ira oncogene, te whakakore rānei i ngā ira pehi pukupuku.
3. Te mate Klinefelter: Ko te tohu o te nui rawa o te kotahi, neke atu rānei o ngā ira X i roto i ngā tāne.
4. Te Mate Turner: I puta mai i te monosomy X, arā, kotahi anake te ira X o te wahine.
Ngā Rangahau ā-Māui i te Marae o ngā Chromosome
Ko ngā rangahau anō mō te hanganga me te mahi o ngā ira-ira e whai ana kia nui ake te māramatanga mō ngā mate ira me te mate pukupuku, me te kimi huarahi hei whakawhanake i ngā rongoā hou. Hei tauira, ko te mārama ki te tūranga o ngā whakarerekētanga hysteresis i roto i te whakahaere ira kua whakatuwhera i ngā huarahi hou mō te whakawhanaketanga rongoā ka taea te whakarerekē, te arotahi rānei ki ēnei whakarerekētanga hei rongoā i te mate.
Whakamutunga
He hoahoa uaua engari he hoahoa whakarite te hanganga o ngā ira i roto i te karihi eukaryotic e whakarite ana i te rokiroki tika, te whakapuakitanga, me te whakawhiti i ngā mōhiohio ira. Ehara i te mea ko ngā ira anake he aho DNA; he taputapu tika mō te ora, e whakaata ana i te taurite tino pai i waenga i te pumau me te ngāwari o te ira. Mā te mārama ki ngā ira, ehara i te mea ka hurahia e tātou ngā mea ngaro o te ora engari ka whakatakoto hoki i te ara mō ngā whanaketanga hauora me te hangarau koiora ā muri ake nei.
