Qhov sib txawv tseem ceeb ntawm kev rov ua dua thiab kev hloov pauv yog qhov kev rov ua dua yog cov txheej txheem uas tsim ob daim ntawv theej zoo ib yam ntawm DNA los ntawm thawj DNA molecule thaum transcription yog thawj kauj ruam ntawm noob qhia uas tsim mRNA molecule los ntawm DNA qauv.
Cells faib thiab nce tus lej txhawm rau kom loj hlob thiab txhim kho. Tsis tas li ntawd, kev tsim cov qe menyuam yog tsim nyog los tswj lawv cov tiam. Lub voj voog ntawm tes yog cov xwm txheej cuam tshuam txog kev tsim cov ntxhais tshiab ntawm lub cell. Thaum lub sij hawm lub voj voog ntawm tes, ob txheej txheem hu ua replication thiab transcription yog qhov tseem ceeb tshaj plaws. Nws yog vim hais tias replication pab txhawb kev sib kis ntawm caj ces cov ntaub ntawv mus rau tiam tom ntej thaum lub transcription pab txhawb zus tau tej cov proteins uas tsim nyog rau lub nuclear division. Ob qho tib si replication thiab transcription tshwm sim ntawm interphase ntawm lub voj voog ntawm tes tab sis, ntawm cov theem sib txawv.
Dab tsi yog Replication?
DNA rov ua dua yog txheej txheem uas tsim ob daim qauv ntawm DNA los ntawm tus thawj DNA molecule. Nws yog cov txheej txheem nyuaj uas tshwm sim thaum lub sijhawm S (synthesis) ntawm lub voj voog ntawm tes. Yog li, DNA replication ua rau muaj txiaj ntsig zoo ntawm cov ntaub ntawv caj ces khaws cia hauv niam txiv DNA los ntawm cov neeg laus. Tsis tas li ntawd, thaum lub sij hawm replication txheej txheem, ob strands ntawm DNA ua hauj lwm raws li templates. Li no, nws tshwm sim nyob rau hauv ib tug semi-conservative yam.
Tsis tas li ntawd, ib pawg enzymes hu ua DNA polymerases; cov topoisomerase, DNA helicase, DNA primase, thiab DNA ligase, koom nrog hauv DNA replication txheej txheem. Nrog kev pab los ntawm luv luv RNA primer, DNA replication txheej txheem pib. Thiab, DNA helicase yog lub enzyme uas cais los yog unwinds ob DNA strands nyob rau hauv thiaj li yuav siv cov templates rau tsim ntawm tshiab strands. Tsis tas li ntawd, DNA replication tshwm sim ob-directionally pib los ntawm qhov chaw hu ua replication fork.
Daim duab 01: DNA Replication
Vim muaj ob txoj hlua, ob txoj hlua tshiab; ua strand thiab lagging strand daim ntawv ntawm qhov kawg ntawm cov txheej txheem replication. Leading strand yog DNA tshiab strand uas synthesizes tsis tu ncua thaum lub lagging strand yog thib ob tshiab strand uas synthesizes li tej daim (Okazaki fragments). Qhov sib ntxiv ntawm nucleotides los ntawm DNA polymerase tshwm sim nyob rau hauv cov kev taw qhia ntawm 3' rau 5'. Nws kuj pab txhawb kev ua pov thawj hauv tib qho kev taw qhia kom tshem tawm cov khub tsis sib xws.
Kev txhais lus yog dab tsi?
Kev txhais lus yog thawj kauj ruam ntawm cov noob qhia nyob rau hauv uas cov ntaub ntawv noob caj noob ces khaws cia rau hauv cov txheej txheem coding ntawm cov noob luam rau hauv mRNA ib ntus txhawm rau tsim cov protein. Nws yog cov txheej txheem enzyme-tsav. Qhov tseeb, RNA polymerase yog lub ntsiab enzyme uas catalyzes cov ntawv sau. Muaj peb kauj ruam tseem ceeb ntawm kev sau ntawv uas yog pib, elongation thiab xaus. Cov txheej txheem kev hloov pauv pib sai sai tom qab khi RNA polymerase thiab cov txheej txheem hloov pauv nrog cov txheej txheem txhawb nqa nyob rau sab saud mus rau chav pib pib. Qhov kev khi no tsim kom muaj cov npuas ntawm cov ntaub ntawv sau tseg.
Daim duab 01: Kev txhais lus
Thaum qhov chaw pib pib qhov pib, RNA polymerase catalyzes ntxiv ntawm ribonucleotides txhawm rau tsim mRNA ib ntus. Yog li ntawd, nws synthesizes thawj mRNA transcript los ntawm kev nyeem cov antisense DNA strand nyob rau hauv cov kev taw qhia ntawm 3' rau 5'. Qhov no ua rau ib qho RNA strand uas yog sib ntxiv thiab sib piv rau cov qauv strand tab sis muaj cov kab mob caj ces ntawm qhov kev nkag siab ib ntus. Cov txheej txheem kev hloov pauv xaus los ntawm kev ntxiv ib tus Tsov tus tw polyadenine thaum RNA polymerase tau txais lub teeb liab txiav. Hauv prokaryotes, ntxiv rau polyadenine tus Tsov tus tw, 5'end capping thiab exon splicing tshwm sim raws li kev hloov pauv tom qab kev hloov pauv.
Dab tsi yog qhov Zoo sib xws ntawm Kev Tshaj Tawm thiab Kev Tshaj Tawm?
- Replication thiab transcription yog cov txheej txheem nyuaj.
- Lawv yog cov txheej txheem tswj tau zoo uas tshwm sim ntawm qib cellular.
- Tsis tas li, ob qho tib si replication thiab transcription tshwm sim thaum lub voj voog ntawm tes, thiab lawv tseem ceeb rau kev ua tiav ntawm lub voj voog ntawm tes.
- Tsis tas li ntawd, lawv yog cov tshuaj tiv thaiv enzyme-catalyzed uas tau tsav hauv 3' mus rau 5' kev taw qhia.
- Tsis tas li ntawd, ob qho tib si txheej txheem ua peb kauj ruam tseem ceeb; kev pib, elongation, thiab txiav.
- Dhau li ntawd, DNA unwinding yog ib qho tseem ceeb tshwm sim nyob rau hauv ob qho tib si txheej txheem.
Qhov txawv ntawm Kev Tshaj Tawm thiab Kev Tshaj Tawm yog dab tsi?
Kev rov ua dua thiab kev hloov pauv yog ob qhov xwm txheej tseem ceeb uas tshwm sim hauv lub hlwb ntawm cov kab mob muaj sia. Replication yog tus txheej txheem ntawm luam ib DNA molecule thiab tsim replicas ntawm nws. Ntawm qhov tod tes, transcription yog thawj kauj ruam ntawm cov noob qhia nyob rau hauv uas cov nucleotide ib theem zuj zus ntawm coding sequence yog theej rau hauv ib mRNA molecule. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm kev rov ua dua thiab hloov pauv. Hauv kev rov ua dua, ob qho tib si DNA strands ua haujlwm raws li cov qauv thaum hloov pauv, tsuas yog cov antisense DNA sib lawv liag ua tus qauv. Li no, nws yog lwm qhov sib txawv ntawm replication thiab transcription.
Tsis tas li ntawd, ib qho sib txawv ntawm kev rov ua dua thiab kev hloov pauv yog qhov DNA polymerase catalyzes replication thaum RNA polymerase catalyzes cov ntawv sau. Ntxiv mus, replication xav tau RNA primer thaum transcription tsis xav tau primer. Yog li, qhov no kuj yog qhov sib txawv ntawm kev luam thiab luam tawm.
Cov hauv qab no nthuav tawm cov ntsiab lus ntxiv ntawm qhov sib txawv ntawm kev rov ua dua thiab kev sau.
Summary – Replication vs Transcription
Replication thiab transcription yog ob yam xwm txheej uas tshwm sim thaum lub voj voog ntawm tes. Ob qho txheej txheem tshwm sim hauv cov nucleus tab sis tshwm sim vim ob lub hom phiaj sib txawv. Replication tshwm sim txhawm rau xa cov ntaub ntawv caj ces mus rau tiam tom ntej thaum qhov kev hloov pauv tshwm sim txhawm rau tsim cov protein. Hauv cov ntsiab lus, qhov sib txawv tseem ceeb ntawm kev rov ua dua thiab kev hloov pauv yog qhov tshwm sim molecule. Replication tsim ob daim ntawv theej zoo ib yam ntawm DNA thaum cov ntawv sau ua ib qho mRNA molecule.
