He aha te mea te whakahuahua o DNA? Ko te tukanga o te pītauira

Kei te i roto i te hanganga pūira - te rāpoi ngota pītauira. Kei Kotahi pūira te muingota kotahi arā, o rua ngā whenu. Whakahuahua o te DNA - ko te whakawhiti o ngā kōrero i muri i te whaiaro reproduction-o miro i tetahi rāpoi ngota ki tetahi. Tei roto te reira e rua DNA me te RNA. E aparau teie nei tuhinga te tukanga tukuruatanga DNA.

mōhiohio General me ngā momo o te DNA kōtuitanga

Kei te mohiotia te reira e miro miro i te rāpoi ngota. Heoi, ka haamata te tukanga o te tāruaruatanga DNA, dispiralized ratou, ka sitepu peka, a ki runga ki ia kape hou synthesized te. Runga ki te whakaotinga i reira e rua ngā rāpoi ngota tino ōrite, ia o nei i reira ko te matua me te miro tamaiti. huaina ana tēnei ariā ko āhua-momo. E oho rāpoi DNA, i toe i roto i te centromere kotahi, a pae hopea mahuetanga anake ka haamata tenei tukanga wehenga centromere.

huaina ana te tahi atu ahua te kōtuitanga reparative. Ia, i rite ki te kotahi o mua, e kore e pā ana ki tetahi atamira pūtau, engari tīmata i roto i te hui o DNA kino. Ki te rawa whānui-ā ratou natura, iku mate te pūtau. Heoi, ki te he te rohe o nga kino, ka koe e taea e whakahoki ratou. Tei runga i te raruraru ki te kia whakahokia wehe nga whenu e rua o te DNA i kotahi ranei. Tenei, e kiia ana ko, kōtuitanga mau hooraa e kore e tangohia i te wa roa, me te kore e rapu i te rota o te pūngao.
Otira i te mea he whakahuahua o te DNA, ka pau te rota o te pūngao, rauemi, totoro te roa o tona tiaki.
Kei te wehea whakahuahua ki wā e toru:

• tomokanga;
• elongation;
• whakamutunga.

Kia whakaaro tatou te raupapa o pītauira.

tomokanga

I roto i te DNA tangata - he torutoru tekau o miriona o takirua turanga (te kararehe tatau ratou anake i te rau me te iwa). tīmata DNA whakahuahua i roto i nga wahi maha i te mekameka mo nga take e whai ake. Huri noa te wa taua i roto i te RNA puta te tuhi, engari i roto i te kōtuitui o DNA iri te i roto i te tahi mau o te wāhi tīpakohia. Na reira, he tukanga taua ki te aroaro o te nui rawaka o te taonga piki i roto i te cytoplasm o ngā pūtau i roto i te tikanga ki te tautoko i ira kīanga me te mahi pūtau kore i i i pakaru. I roto i te tirohanga o tenei, kia tango i te tukanga wahi rite hohoro rite taea. Te pāho i roto i tenei wā kawea ki waho, a kahore te te patohanga whakahaere. Kua whakaaturia Studies e kotahi DNA whakahuahua puta i roto i te maha mano ngā - ngā wāhi iti ki te raupapa nucleotide motuhake. E piri ratou e pūmua initiator motuhake, i roto i te tahuri honoa e te tahi atu whākōkī o pītauira.

huaina te kongakonga DNA synthesized nei ko te replicon. E haamata te reira i te tīmatanga, me te mutu ka Aukatihia ai te whākōkī tukuruatanga. he motuhake Replicon, a te kaiwhakawhiwhi hoki te tukanga katoa o tona pūmanawa ake.
E kore e tīmata i te tukanga i ngā katoa i kotahi, vahi haamata te reira i mua, wahi - i muri mai; Ka taea e te tango i te reira i te wahi i roto i te kotahi i roto i te rua ngā tohutohu ritenga ranei. Ko te ngā tango i te wahi i roto i te raupapa e whai ake nei, no te te whakapakoko:

• marau tukuruatanga;
• tämata RNA.

marau tukuruatanga

E whakaatu ana tēnei wāhanga he tukanga i roto i te ngangana momotu e synthesized ai kakawaea deoxyribonucleic DNA. Kōhao te kupu hanga te kanohi pera-ka karanga o tukuruatanga. mua te tukanga e te maha o ngā mahi:

• te tuku i te hononga ki te histones i roto i te nucleosome - whākōkī pēnei i te methylation te tāruaruatanga DNA, acetylation, me phosphorylation hua tauhohe matū e hua i roto i te pūmua ngaro ratou tiaki pai e whakahaere to ratou tuku;
• despiralization - he taui, e te mea e tika ana mo te whakaoranga anō o ngā miro;
• whatiia hauwai here i waenganui i ngā whenu DNA;
• ratou hahiraa i roto i te taha rerekē o te rāpoi ngota;
• warea e puta ana te whakamahi i SSB pūmua.

tämata RNA

mauria e Synthesis he paru i huaina DNA polymerase. Heoi, ki te tīmata i tana ake e kore e taea e ia, na te mahi i te tahi atu whākōkī - te polymerase RNA, kua karangatia e hoki nei primers RNA. E synthesized ratou i roto i ngā whenu whakarara o deoxyribonucleic i runga i te parau tumu o te kïnakitanga. Ko te kupu, mahue haea te tomokanga o te RNA ariā o te pito e rua, e rua primers me motu whenu DNA.

elongation

tīmata tēnei wā i tua atu nucleotide, me 3 'mutunga o te RNA-tämata, e te maua e te polymerase DNA kua whakahuatia. piri te reira ki te rua o te tuatahi, tuatoru nucleotide, a na i runga i. E hono turanga miro New ki te mekameka matua e here hauwai. Kei te whakapono te reira e te ariā o te miro, ko te roto i te 5 '- 3'.
Hea puta te reira i roto i te taha o te marau te tāruaruatanga, e te ariā wahi tonu me i whakaroa te wa taua. Na reira, i huaina tenei miro ko te ārahi ranei ārahi. RNA ia te kore te tämata i hanga.

Heoi, i runga i te whenu ritenga o te matua tonu DNA nucleotides ki uru atu te tämata RNA, ka synthesized mekameka deoxyribonucleic te i roto i te huarahi i te ritenga i te marau tukuruatanga. I roto i tenei take, e kiia ana ko te hekenga ërä ranei.

I runga i te whenu ërä puta te kōtuitanga i roto i nga whatiwhatinga, ai haamata tetahi wahi mutunga o te kōtuitui i tetahi wāhi e tata ana ki te whakamahi i taua tämata RNA taua. Ko te kupu, i reira e kua piri rua kongakonga mekameka roa te DNA me te RNA. E huaina ratou Okazaki whatiwhatinga.

Na ka korerotia nga mea katoa te. Na ka kanawa tetahi atu tahuri o te helix, hauwai pakaru miro kōrero ki te taha, ārahi mekameka roa i te ërä synthesized whai kongakonga RNA tämata, taunga nei - Okazaki kongakonga. Muri, i roto i te RNA whenu-roa e ngaro primers me e piri nga whatiwhatinga DNA ki tetahi. Na tenei ara iahiko e wahi i te wa ano:

• te hanganga o te tämata RNA hou;
• ariā o Okazaki whatiwhatinga;
• whakangaromanga o primers te RNA;
• toe fakataha ki te taiawhio kotahi.

whakamutunga

tonu rite te roa ki te tukanga rite te rua kahore e whakatau i te marau tāruarua, tetahi o ratou e haere mai ki te mutunga o te rāpoi ngota ranei. I muri i te hui, e piri whenu tamahine marau DNA i te whākōkī. I roto i te take, ki te oho te plug te ki te mutunga o te rāpoi ngota, pito DNA whakahuahua whakamahi whākōkī motuhake.

te ako

I roto i tenei tukanga, whakaritea he wāhi nui te ki te mana (te ako ranei) o tukuruatanga. Hei tuu kōtuitanga e tango momo katoa e wha o nucleotides, me te uiuia i te pairing DNA polymerase kōwhiria e te hunga e e hiahiatia.

Ko te nucleotide hiahiatia ki te taea ki te hanga i here hauwai me te nucleotide rite i runga i te whenu tātauira DNA. I tua atu, i waenganui i te tapahanga huka-Phosphate me whai he tetahi tawhiti tamau e ōrite ana ki te toru mowhiti i nga turanga e rua. Ki te kore e whakatau i te nucleotide enei whakaritenga, e kore te hononga e puta.
kawea Mana i roto i te aroaro o te whakaurua ai ki te ara iahiko, me te i mua i tahuri i runga i te nucleotide muri. I muri i taua, ko te hononga ki te saharofosfata tapahanga.

rerekētanga mutational

Ko nga wa katoa raruraru i roto i te kakawaea, e te hunga kua huaina te nuinga te tikanga o te pītauira, ahakoa te ōrau teitei o te tika "irakētanga ira." Mō te mano takirua turanga, i reira he kotahi hape e konvariantnaya huaina whakahuahua.

tupu te reira i hoki take rerekē. Hei tauira, i nohanga teitei ranei iti rawa o nucleotides deamination o cytosine, aroaro o mutagens i te kōtuitui o rua. I roto i ētahi wā, ka taea te papaki te hapa i ngā tukanga hanga i roto i te tahi atu te ako riro taea.

Ki te pāngia te kino te wāhi moe, e kore he hapa e whai nunu'a mamafa ka reira he tukanga tukuruatanga DNA. Nucleotide raupapa o te ira e taea puta ki hapa kahui. Na ehara i te mea te take, a ka taea e te hua kino kia rite te mate o te pūtau, me te mate o te rauropi katoa. kia hoki kia whanau te reira i roto i te ngakau e irakētanga ira hāngai e runga rerekētanga mutational, e hanga te puna ira o plasticity.

methylation

I te wa o te ariā, i muri ranei tonu puta reira mekameka methylation. Kei te whakapono te reira e te mea e tika ana tenei tukanga hoki ki te tangata te hanga i ngā pūira, me te whakahaere i ira tuhi. I roto i tenei tukanga huakita o DNA tavini tona tiaki ki te tapahi whākōkī.