DNA polymerase tsuas yog taug kev mus rau qhov twg?
DNA polymerase tsuas yog taug kev mus rau qhov twg?

Video: DNA polymerase tsuas yog taug kev mus rau qhov twg?

Video: DNA polymerase tsuas yog taug kev mus rau qhov twg?
Video: Пеб цев нейг тауг уа саб уа суа 20.07.2017 2024, Kaum ib hlis
Anonim

Txij li thaum DNA polymerase yuav tsum muaj 3 'OH pab pawg pub dawb rau kev pib ntawm synthesis, nws tuaj yeem ua rau hauv nkaus xwb ib kev taw qhia los ntawm kev txuas ntxiv 3 'kawg ntawm cov saw hlau nucleotide preexisting. Vim li no, DNA polymerase txav raws tus qauv strand hauv 3'-5' kev taw qhia , thiab tus ntxhais strand yog tsim nyob rau hauv ib tug 5'-3' kev taw qhia.

Kuj tseem paub yog, vim li cas DNA replication tsuas tshwm sim hauv 5 mus rau 3 kev taw qhia?

Teb thiab piav qhia: DNA replication tsuas yog tshwm sim hauv 5' rau 3 ' kev taw qhia vim DNA polymerase yuav tsum tau dawb 3 ' hydroxyl pab pawg kom txuas cov nucleotide tshiab rau.

Ib yam li ntawd, DNA replication tshwm sim li cas? Replication tshwm sim nyob rau hauv peb cov kauj ruam loj: qhib ob lub helix thiab sib cais ntawm lub DNA strands, priming ntawm template strand, thiab lub rooj sib txoos ntawm cov tshiab DNA ntu. Thaum sib cais, ob txoj hlua ntawm lub DNA ob chav helix uncoil ntawm ib qho chaw tshwj xeeb hu ua keeb kwm.

Raws li txoj cai, vim li cas DNA polymerase ua haujlwm nyob rau hauv cov lus qhia tawm?

Qhov tseeb tias DNA strands nyob rau hauv ib tug ob helix khiav nyob rau hauv ntxeev lus yog ib qho teeb meem rau cov rov ua dua machinery, vim DNA polymerase tuaj yeem tsuas ntxiv cov hauv paus hauv ib qho kev taw qhia , los ntawm 5'-3' (5'-3' tsuas yog ib txoj hauv kev qhia txog kev taw qhia ntawm DNA strands).

Txoj kev 5 mus rau 3 yog dab tsi?

2 Teb. Cov 5 ' thiab 3 ' txhais tau tias " tsib prime" thiab " peb prime", uas qhia cov lej carbon nyob rau hauv DNA lub qab zib qaum 5 ' carbon muaj ib pawg phosphate txuas rau nws thiab 3 ' carbon a hydroxyl (-OH) pawg. Qhov no asymmetry muab DNA strand ib " kev taw qhia ".

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