Video: Lub hom phiaj ntawm DNA supercoiling yog dab tsi?
2024 Tus sau: Miles Stephen | [email protected]. Kawg hloov kho: 2023-12-15 23:36
DNA supercoiling yog ib qho tseem ceeb rau DNA ntim hauv txhua lub cell. Vim qhov ntev ntawm DNA tuaj yeem ua tau ntau txhiab zaus ntawm lub xov tooj ntawm tes, ntim cov khoom siv caj dab no rau hauv lub cell lossis nucleus (hauv eukaryotes) yog qhov nyuaj. Supercoiling ntawm DNA txo qhov chaw thiab tso cai rau DNA kom tau ntim.
Ntawm no, dab tsi ua rau DNA supercoiling?
Supercoiling . Thaum lub DNA helix muaj tus lej ntawm lub hauv paus khub ib helical tig nws nyob rau hauv lub xeev so. Supercoiling tshwm sim thaum lub molecule relieves helical kev nyuaj siab los ntawm twisting nyob ib ncig ntawm nws tus kheej. Overtwisting ua rau positive supercoiling , thaum undertwisting ua rau tsis zoo supercoiling.
Tom qab, lo lus nug yog, vim li cas DNA feem ntau tsis zoo supercoiled? Prokaryotes thiab Eukaryotes feem ntau muaj tsis zoo supercoiled DNA . Tsis zoo supercoiling yog ib txwm tshwm sim vim tsis zoo supercoiling npaj cov molecule rau cov txheej txheem uas yuav tsum tau sib cais ntawm cov DNA strands. Topoisomerases unwind helix ua DNA transcription thiab DNA rov ua dua.
Yog li ntawd, lub luag haujlwm ntawm topoisomerases hauv DNA supercoiling yog dab tsi?
Topoisomerases yog cov enzymes uas koom rau hauv lub overwinding los yog underwinding ntawm DNA . Qhov teeb meem winding ntawm DNA tshwm sim vim qhov intertwined xwm ntawm nws ob-helical qauv. Thaum DNA replication thiab transcription, DNA ua overwound ua ntej ntawm replication diav rawg.
Dab tsi yog Supercoiling hauv biology?
Kev kho mob txhais ntawm supercoil : ob lub helix (raws li ntawm DNA) uas tau dhau mus ntxiv twisting nyob rau hauv tib txoj kev raws li los yog nyob rau hauv lub opposite kev taw qhia ntawm lub lem nyob rau hauv thawj helix. - tseem hu ua superhelix.
Pom zoo:
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