Te Hononga i waenga i te DNA me te RNA i roto i te Whakapuakitanga Ira
Ko te whakaaturanga ira te tukanga e whakamahia ai ngā mōhiohio ira e rongoatia ana i roto i ngā pūtau hei whakaputa hua mahi, ko ngā pūmua te nuinga, e whakatau ana i te hanganga me te mahi a ngā rauropi. I roto i tēnei tukanga, he tino tata, he hononga tautoko hoki te DNA me te RNA. He "pūranga" pumau te mahi a te DNA mō ngā mōhiohio ira, ko te RNA ia he "takawaenga" me te "kaiwhakahaere," e āwhina ana ki te whakamāori i aua mōhiohio ki ngā ngota mahi i roto i te pūtau. He mea nui te mārama ki te whanaungatanga i waenga i te DNA me te RNA i roto i te whakaaturanga ira hei whakamārama i te tipu, te urutau, me te urupare a ngā pūtau ki tō rātou taiao.
Te DNA hei puna mōhiohio ira
Ko te DNA (deoxyribonucleic acid) he ngota e pupuri ana i ngā tohutohu ira i roto i te ahua o te raupapatanga o ngā nucleotide. E whā ngā turanga hauota o te DNA: adenine (A), thymine (T), guanine (G), me te cytosine (C). Mā te raupapatanga o ēnei turanga ka hangaia he ira, arā, he wāhanga o te DNA kei roto ngā mōhiohio e hiahiatia ana hei hanga RNA me/ngā pūmua motuhake. Ko te DNA te nuinga o te wā ka kitea i roto i te karihi o ngā rauropi eukaryotic, ko ngā prokaryote ia, ka kitea i roto i te rohe nucleoid o te cytoplasm.
Ko te painga matua o te DNA hei rauemi ira ko tōna pumau. Nā tōna hanganga takirua-helix me te noho mai o te thymine (kaua ko te uracil) ka kaha ake te ātete o te DNA ki ngā kino matū. Hei tāpiri, he tikanga whakatika whai hua tō te DNA. Nā tēnei ka pai mō te rokiroki mōhiohio mō te wā roa. Heoi, ko te tikanga o tēnei pumau kāore te DNA e "mahi tika" ki te whakahaere i ngā mahi pūtau; me whai takawaenga hei whakamahi i ana mōhiohio.
RNA hei hononga me te kaiwhakahaere
Ko te RNA (waikawa ribonucleic) he ngota ngota e rite ana te hanganga ki te DNA engari he maha ngā rerekētanga nui. Ko te RNA he aho kotahi te nuinga, kei roto ko te ribose huka, ā, e whakamahi ana i te uracil (U) hei utu mō te thymine (T). Mā ēnei rerekētanga ka ngāwari ake te RNA, ka māmā ake hoki te hanga ki ngā hanganga toru-ahu rerekē, ka taea ai e ia te mahi i ngā mahi maha i roto i te pūtau.
E kitea mārama ana te whanaungatanga i waenga i te DNA me te RNA i roto i te ariā o te "whakaaro matua" o te koiora ngota: ka rere ngā mōhiohio ira mai i te DNA ki te RNA, kātahi mai i te RNA ki te pūmua. Ahakoa he rerekētanga kei tēnei ariā (hei tauira, te whakahurihuri i roto i ngā retrovirus), i te nuinga o te wā, ko tēnei rere o ngā mōhiohio te pūtake mō te whakaaturanga ira.
Te wāhanga tuatahi: te whakawhiti ira (DNA ki te RNA)
Ko te taahiraa tuatahi e hono ana i te DNA me te RNA ko te tuhi, arā, te tukanga tārua i ngā mōhiohio mai i te DNA ki te RNA. I tēnei wāhanga, ka piri te whākōkī RNA polymerase ki tētahi rohe motuhake o te DNA e kiia nei ko te kaiwhakatairanga, kātahi ka whakatuwhera i tētahi wāhanga o te helix takirua hei pānui i tētahi o ngā aho DNA hei tauira. Kātahi ka huihuia e te RNA polymerase ngā nucleotides RNA tautoko: A me U, T me A, G me C, me C me G.
Ko te hua o te whakawhiti ira he ngota RNA e kiia nei ko te whakawhiti ira. Mena he ira e whakakōrero ana i te pūmua te ira, ko te whakawhiti ira he RNA karere (mRNA). Ka haria e te mRNA te "karere" i roto i te ahua o te waehere ira mai i te DNA ki ngā ribosome, te wāhi e hangaia ai ngā pūmua. I roto i ngā eukaryote, ka puta te whakawhiti ira i roto i te karihi pūtau, i roto i ngā prokaryote, ka puta i roto i te cytoplasm.
Ehara i te mea ko te tārua noa i ngā mōhiohio te tukanga whakawhiti kōrero; he pūwāhi whakahaere nui anō hoki. Ka taea e ngā pūtau te whakahaere i ngā ira e "kā ana" ana, e "wā kore rānei" ana mā te whakahaere i te urunga atu o te RNA polymerase ki ngā kaiwhakatairanga mā roto i ngā pūmua whakahaere pērā i ngā take whakawhiti kōrero, ngā kaiwhakaoho, me ngā kaiwhakaiti.
Te tukatuka RNA i roto i ngā eukaryote: mai i te pre-mRNA ki te mRNA pakari
I roto i ngā eukaryote, kāore te mRNA i te rite tonu mō te whakamahi i muri i te tuhi. Ko te hua tuatahi ka kiia ko te pre-mRNA, kei roto tonu i tēnei ko ngā rohe kore-kōwae (intron) me ngā rohe kōwae (exons). Me whai i ētahi mahi a te pre-mRNA:
1. Te tāpiri i te taupoki 5', he whakarerekētanga tēnei i te pito 5' hei āwhina i te tiaki i te mRNA mai i te pirau, hei āwhina hoki i te herenga o te ribosome.
2. Te honohono, arā, te tango i ngā intron me te hono i ngā exon. Ka mahia tēnei tukanga e te matatini spliceosome. Mā te honohono ka taea hoki te honohono rerekē, ka taea e ngā huinga rerekē o ngā exon te whakaputa i ngā pūmua rerekē mai i te ira kotahi.
3. Te tāpiri i te hiku poly-A ki te pito 3', e whakapiki ana i te pumau o te mRNA, ā, e āwhina ana hoki ki te kawe i te mRNA ki waho i te karihi.
E whakaatu ana tēnei tukatuka i tētahi whanaungatanga uaua ake i waenga i te DNA me te RNA: ko te DNA te tauira taketake, ko te RNA ia ka taea te "whakarerekē" hei whakaputa i ngā momo hua maha atu i te maha o ngā ira kei roto.
Te wāhanga tuarua: te whakamāoritanga (RNA ki te pūmua)
Kia pakari te mRNA, ko te wāhanga e whai ake nei ko te whakamāoritanga, arā, te tukanga e huri ai te raupapa nucleotide mRNA ki te raupapa waikawa amino hei hanga i tētahi pūmua. Ka puta te whakamāoritanga i roto i ngā ribosome, he mea tito mai i te rRNA (RNA ribosomal) me ngā pūmua.
Ka pānuihia e ngā ribosome te mRNA i roto i ngā rōpū o ngā nucleotide e toru e kiia nei ko ngā codon. Ka waehere ia codon mō tētahi waikawa amino motuhake. Kei roto i te ngota tRNA (transfer RNA) te waikawa amino e tika ana, ā, he anticodon tōna e hono ana ki te codon i runga i te mRNA. Ina herea te tRNA tika, ka huihuia e te ribosome ngā waikawa amino ki roto i tētahi mekameka polypeptide kia tae rā anō ki tētahi codon mutu, e tohu ana i te mutunga o te whakamāoritanga.
I konei, ka tirohia te whanaungatanga i waenga i te DNA me te RNA hei raupapa mahi: ka rongoatia e te DNA ngā tohutohu, ka kawehia e te mRNA ngā tohutohu, ka whakamāoritia e te tRNA ngā tohutohu, ā, ko te rRNA te mīhini e whakahaere ana i te huihuinga pūmua.
Ētahi atu momo RNA e awe ana i te whakaaturanga ira
Haunga te mRNA, te tRNA, me te rRNA, he maha atu ngā momo RNA e whai wāhi ana ki te whakaaturanga ira, inā koa ki te whakahaere. Hei tauira:
– miRNA (microRNA) me siRNA (RNA iti e ārai ana): Ka taea e ēnei RNA iti te here ki ngā mRNA motuhake, ka whakangaromia, ka āraihia rānei tā rātou whakamāoritanga. Nō reira, he mahi tika tā te RNA ki te "whakaweto" i te whakaaturanga ira.
– lncRNA (RNA roa kore-waehere): He mahi tā te RNA roa kore-waehere ki te whakahaere i te whakaaturanga ira mā roto i ngā momo tikanga, pērā i te kohikohi i ngā pūmua whakarerekē-chromatin, te awe rānei i te pumau o te mRNA.
– snRNA (RNA karihi iti): he wāhanga nui o te spliceosome mō te hononga intron-exon.
Ko te noho mai o ngā RNA whakahaere e kī ana ehara te whanaungatanga i waenga i te DNA me te RNA i te ara kotahi noa iho. Ka taea e te RNA te whakarerekē i te nui o ngā mōhiohio DNA e whakamāoritia ana ki ngā pūmua, te wā, me ngā momo pūtau motuhake.
Te whakahaere i te whakaaturanga ira: ngā pūwāhi whakahaere mai i te DNA ki te RNA
Kāore e whakaatuhia e ngā pūtau ngā ira katoa i ngā wā katoa. Ka taea te whakahaere i te whakaaturanga ira i ngā taumata maha, ko te nuinga:
1. Te whakahaere i te DNA/chromatin (eukaryotic anake): Ka taea te whakapoto, te whakaputa rānei i te DNA mā roto i ngā whakarerekētanga histone me te methylation DNA. He uaua te tuhi i te DNA kua tino whakapoto.
2. Te whakahaere i te whakawhiti kupu: mā ngā āhuatanga whakawhiti kupu ka whakatau mēnā ka taea e te RNA polymerase te tīmata i te whakawhiti kupu.
3. Te whakahaere i muri i te whakawhiti: kei roto ko te honohono rerekē, te whakatika RNA, me te pumau me te kawe mRNA.
4. Te whakahaere i te whakamāoritanga: ka taea te whakamāori tere ake, te puhoi ake rānei te mRNA i runga i te āhua o te pūtau.
5. Te whakahaere i muri i te whakamāoritanga: ka taea te whakarerekē, te whakangaro rānei i ngā pūmua i hangaia ina hiahiatia.
I ia wāhanga, ko te DNA te pūtake o ngā mōhiohio, ko te RNA ia te kaiwhakahaere matua e whakatau ana i te nui o aua mōhiohio ka puta hei hua tūturu.
Whakamutunga
Ko te whanaungatanga i waenga i te DNA me te RNA i roto i te whakaaturanga ira te kaupapa matua o te mahi a te ora i te taumata ngota. Ko te DNA he putunga pumau o ngā mōhiohio ira, ko te RNA ia te kawenga mō te tuhi, te kawe, te whakamāori, tae noa ki te whakahaere i aua mōhiohio. Ka hurihia e te tuhi ngā mōhiohio DNA ki te RNA, ā, ka hurihia e te whakamāori ngā mōhiohio RNA ki ngā pūmua. Hei tāpiri, ka whakawhānui ake ngā momo RNA kore-waehere i te mahi a te RNA hei kaiwhakahaere i te whakaaturanga ira, ka kaha ake te pūnaha me te aro atu ki te taiao. Mā te mārama ki tēnei whanaungatanga ka āwhina i a tātou ki te mārama ake ki te pūtake o te tukunga iho, te whanaketanga o te rauropi, ngā take o ngā mate ira maha, me te kaha mō ngā maimoatanga e ahu mai ana i te ira.
