Isakhiwo DNA ne-RNA isakhiwo

Uma sicabange ukubukeka a molecule ye-DNA kufana Kuvunguza nesisontekile, ezakhiwe ngamaketanga amabili polynucleotide okuyinto okokusonteka phakathi kwakhe ne-kanyekanye emhlabeni omunye izimbazo zabo ezivamile okuyinto.

Ngokuvamile, isakhiwo DNA kubhekwa ngaphakathi ohlelweni ukuhlaziywa, lapho njengoba main - esokuba esinqunyiwe (esijwayelekile isimo) inqubo interposition dezoksiribonukleozidmonofosfatov - dNMP, izingxenye polynucleotide chain.

Ngo-non-soguquko lwegciwane singalawuleka iseli mononucleotides wajoyina phosphodiester izibopho, nge ngokwabo Ukuvalwa polynucleotide ngamaketanga Unezinketho ezimbili ngoba indawo amaqembu zangempela ngesikhathi 5'-ekupheleni iketango is iqembu phosphate, futhi iqembu OH ungaphakathi circuit Z'-sekupheleni.

Uma sicabanga molecule ehlanganisa imicu emibili, isakhiwo DNA yokuthi iketango polynucleotide kuyoba antiparallel komunye nomunye. Kulesi wesifunda wasigcina isakhiwo okunjalo kuyoba ngenxa hydrogen izibopho ezikhona phakathi izisekelo A-T ne-GC, coplanar, perpendicular eksisi eyinhloko yezinhlayiya Kuvunguza. Labo ekuxhumaneni hydrophobic, akhiwa phakathi izisekelo molecule anjalo, zizenza ukuba zizinze yonkana double helix. Ukuze ezinjalo molecule isakhiwo DNA libhekene complementarity ka polynucleotide ngamaketanga, kodwa hhayi bazikhohlwe ukuthi nucleotide yabo Ukwakheka kuyahluka.

Ngaphezu kwalokho, uma ucabanga ukuthi isakhiwo DNA, kufanele kuphawulwe ukuthi ngalinye elithwala oyedwa "igcwele" ngendlela, chromosome ahlukene ngokuqinile esiyingqayizivele. Lezi-chromosomes aqukethe ezihlukahlukene amaprotheni ezihambisana ukulandelana ngokuqinile kuchazwe isakhiwo DNA. Lezi amaprotheni zihlukaniswa 2 izigaba: histones namaprotheni negistony. Esikhathini eziyinkimbinkimbi ne-DNA enuzi amaseli, lezi amaprotheni abizwa ngokuthi ama chromatin.

Echaza isakhiwo DNA, kufanele kuphawulwe ukuthi chromatin siqukethe izinhlobo ezinhlanu histones, inani icala omuhle esihlinzeka isibopho histones enamandla kakhulu nge-DNA. I eziyinkimbinkimbi histones kanye nezinhlayiya ze-DNA ingxenye echaziwe befaka 146 nucleotide ngazimbili, is abasabela ngayo, lapho akha nucleosomes.

Afakwe isakhiwo namaprotheni DNA negistony ukumela ahlukahlukene izinhlobo amaprotheni zokulawula, ehambisana ne-ikakhulukazi DNA ukulandelana. Futhi, nezinhlayiya ze-DNA ongumphelelisi isakhiwo enzyme ukuhlinzeka biosynthesis.

Tadisha isakhiwo of DNA ne-RNA ngaphakathi ukuhlaziywa uhlelo kufanele kuphela ku eziyinkimbinkimbi, ukuthi, lapho ucabangela isakhiwo DNA, kubalulekile ukuba sicabangele isakhiwo kanye RNA.

isakhiwo zalo eziyinhloko, kanye esimweni a molecule ye-DNA kuyinto algorithm interlace ribonukleozidmonofosfatov, ngaleyo ndlela, kufanele kunakwe ukuthi, ngokungafani DNA, zonke izinhlobo RNA babe kuphela uchungechunge omunye polynucleotide. Ngo isakhiwo engqamuzaneni RNA futhi akhiwa imicu yayo olulodwa, ngakho abizwa ngokuthi "hairpin" - spiralized izihibe okuyizinto AU futhi base GC futhi sisimamiswe ngokusebenzisa i-hydrogen kunenze nisondelane.

Ngokuvamile, ngokwesilinganiso ngobukhulu DNA licishe 150 ngazimbili nucleotide millionov, ubude bawo kuyinto ngamasentimitha amane. Uhlaziyo laboratory ama-molecule anjalo kuzokuhlupha kakhulu cwaningo, ngoba uma ukwabiwa izicubu, i-molecule ivame ukuba wahlukana kakhulu futhi babe ezincane kakhulu ngobukhulu. Ukuqeda leli thuba, in the izifundo indlela PCR - kokuqhuba polymerase chain reaction, e okuyinto ngokukhetha Kuhlanganisa izigaba ngazinye molecule ye-DNA, futhi ukwaba izifundo adingekayo ukuze izingcezwana yayo.