Qhov Tseem Ceeb Qhov txawv - Upstream vs Downstream DNA
Nws yog ib qho tseem ceeb kom muaj kev paub dav dav txog kev muaj pes tsawg leeg thiab cov qauv ntawm DNA kom nkag siab qhov sib txawv ntawm cov dej ntws thiab cov dej hauv qab DNA. DNA yog tsim los ntawm polynucleotide chains. Nucleotides yog lub tsev blocks uas tsim polynucleotide chains thiab txhua nucleotide yog tsim los ntawm peb yam: ib tug tsib-carbon qab zib, ib tug nitrogenous puag, thiab ib pawg phosphate. Ib pawg phosphate thiab ib pawg OH txuas nrog 5 'txoj haujlwm carbon thiab 3' txoj haujlwm carbon ntawm cov piam thaj molecule hauv nucleotide, feem. Nucleotides koom ua ke los ntawm phosphodiester bonds tsim ntawm 5 'phosphate pawg ntawm ib nucleotide thiab 3' OH pawg ntawm cov nucleotide nyob ib sab. Yog hais tias ib tug polynucleotide saw muaj ib tug dawb 5 'phosphate pab pawg neeg, nws yog muab raws li 5' kawg; yog tias nws muaj 3 'OH pab pawg dawb, nws raug muab ua 3' kawg. Yog li, DNA strands feem ntau muaj 5' thiab 3' xaus raws li qhov kawg ntawm cov saw hlau polynucleotide. DNA kuj muaj nyob rau hauv daim ntawv ob-stranded. Ob txoj hlua yog antiparallel rau ib leeg. Yog li, DNA muaj ob txoj hlua uas khiav ntawm 5' mus rau 3' kev taw qhia thiab 3' mus rau 5' kev taw qhia. Upstream thiab downstream DNA yog xa mus nrog rau kev xa mus thiab kev sib txuas ntawm 5' rau 3' mRNA strand. Yog tias DNA raug txiav txim siab ntawm 5 qhov kawg ntawm cov coding strand los ntawm qhov chaw pib transcription nws yog hu ua upstream DNA. Yog tias DNA raug txiav txim siab ntawm 3 'kawg los ntawm coding strand los ntawm qhov chaw pib hloov pauv yog hu ua downstream DNA. Qhov no yog qhov sib txawv tseem ceeb ntawm cov dej ntws thiab nqes dej DNA.
DNA yog dab tsi?
Ib noob yog ib qho kev ua haujlwm thiab kev ua haujlwm ntawm cov noob caj noob ces uas nyob ntawm DNA ntawm lub cev. Nws yog khaws cia nrog cov lus qhia los tsim cov protein. Cov noob muaj ib cheeb tsam tshwj xeeb ntawm DNA molecule. Thaum xav tau, nws sau thiab txhais ua cov protein los ntawm kev sib txuas ntawm mRNA strand. Feem ntau ib coding strand ntawm cov noob khiav ntawm 5 'mus rau 3' kev taw qhia. Thaum nws tau sau tseg, nws tsim ib qho mRNA strand mus rau tib qho kev taw qhia 5' rau 3'. Thaum lub sijhawm sau ntawv, 3 ' txog 5 ' antisense strand tau txais kev pabcuam raws li tus qauv strand thiab pib ua cov mRNA synthesis. Muaj ib qho chaw pib pib ntawm cov noob. Nrog rau kev xa mus rau qhov chaw pib hloov pauv, thaj av DNA ntawm 5 'kawg ntawm cov coding strand yog hu ua cov dej ntws DNA. Ib qho kev txhawb nqa ntawm cov noob yog ib txwm nyob hauv thaj av sab saud ntawm DNA. Hauv cov noob eukaryotic, muaj TATA lub thawv, txhawb nqa cov ntsiab lus sib luag, thiab cov khoom txhawb nqa hauv cheeb tsam nce mus rau cov noob. Cov cheeb tsam sab saud ntawm cov noob raug xa mus nrog cov lej tsis zoo. Upstream DNA ntawm ib lub noob yog qhov tseem ceeb tshaj plaws rau kev hloov pauv.
DNA yog dab tsi?
Kev pib pib qhov chaw yog lub npe hu ua +1 taw tes ntawm cov noob. Lub cheeb tsam DNA los ntawm +1 taw tes rau ntawm 3' kawg ntawm lub coding strand yog hu ua downstream DNA. Nyob rau hauv lwm yam lus, downstream ntawm cov noob yog los ntawm qhov chaw pib transcription mus rau 5 'kawg ntawm lub template strand. Yog li ntawd, hauv qab DNA ntawm ib cheeb tsam gene muaj xws li transcriptional unit thiab lwm yam sequences xws li terminator sequence. Tus neeg txhawb nqa tuaj yeem cuam tshuam cov kab hauv qab ntawm cov noob. Ib feem hauv qab ntawm cov noob raug xa mus nrog cov lej zoo. Downstream DNA ntawm cov noob yog thaj av tiag tiag uas muab cov khoom lag luam protein.
Daim duab 01: Upstream thiab Downstream DNA
Dab tsi yog qhov txawv ntawm Upstream thiab Downstream DNA?
Upstream vs Downstream DNA |
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| DNA cheeb tsam mus rau 5 'qhov kawg ntawm cov txheej txheem coding los ntawm qhov chaw pib transcription yog lub npe hu ua cov dej ntws DNA. | DNA cheeb tsam mus rau 3 'kawg ntawm coding strand los ntawm qhov chaw pib transcription yog hu ua downstream DNA. |
| Elements | |
| Cov neeg txhawb nqa thiab txhawb nqa yog nyob rau ntawm cov dej ntws DNA | Tshaj tawm chav tsev thiab cov terminator sequences nyob rau hauv cov nqes dej DNA. |
| Nucleotides hauv cheeb tsam sab saud raug xa mus nrog tus lej tsis zoo | Nucleotides raug xa mus nrog cov lej zoo. |
| cheeb tsam no muaj cov ntsiab lus tsim nyog los tswj thiab pib sau ntawv | cheeb tsam no muaj cov lus qhia los tsim cov protein thiab txiav cov ntawv sau |
Summary – Upstream vs Downstream DNA
Nws yog ib qho yooj yim los txheeb xyuas cov dej ntws thiab qis ntawm RNA strand. Hais txog qhov chaw siv, thaj tsam ntawm 5' kawg ntawm RNA strand yog lub npe hu ua ntws RNA whereas cheeb tsam mus rau 3' kawg yog hu ua downstream RNA. Txawm li cas los xij, hauv DNA, muaj ob txoj hlua uas khiav hauv ob qho kev qhia 5' rau 3' thiab 3' rau 5'. Yog li ntawd, qhov sib txawv ntawm cov dej ntws thiab cov dej hauv qab DNA yog qhov nyuaj. Yog li ntawd, nws txawv nrog kev siv rau kev hloov pauv ntawm cov noob. Los ntawm qhov chaw pib hloov pauv mus rau 5 qhov kawg ntawm qhov kev nkag siab strand, DNA cheeb tsam yog lub npe hu ua DNA ntws ntws mus rau qhov chaw pib hloov mus rau 3' kawg ntawm qhov kev nkag siab strand hu ua downstream DNA. Qhov no yog qhov sib txawv ntawm cov dej ntws thiab nqes dej ntawm DNA.
