Qhov sib txawv tseem ceeb ntawm pre-mRNA thiab mRNA yog tias pre-mRNA yog thawj cov khoom lag luam ntawm cov noob hloov pauv thiab muaj ob qho tib si tsis-coding sequences (introns) thiab coding sequences (exons) thaum mRNA yog cov khoom thib ob ntawm ib tug transcribed noob uas tsuas muaj coding sequences.
Gene yog qhov ua haujlwm ntawm kev xeeb tub. Nws yog ib ntu DNA tshwj xeeb uas muaj cov kab mob caj ces los tsim cov protein. Cov noob tau dhau los ua ob theem txheej txheem hu ua gene expression. Kev hloov pauv yog thawj kauj ruam uas DNA ib ntus hloov mus rau hauv mRNA ib ntus. Kev txhais lus yog kauj ruam thib ob uas mRNA ib ntus hloov mus rau hauv cov kab ke amino acid. Thaum lub sijhawm sau ntawv, DNA ua ntu zus ua ntej hloov mus rau hauv pre-mRNA molecule uas yog thawj cov ntawv sau uas muaj ob qho tib si coding thiab tsis-coding sequences. Pre-mRNA molecule tsim mRNA (messenger RNA) molecule tom qab tau RNA splicing los yog ua. mRNA sequence tsuas muaj coding sequences.
mRNA yog dab tsi?
Pre-mRNA (precursor mRNA) yog thawj cov ntawv sau tseg thiab cov khoom lag luam tam sim ntawm kev sau ntawv. Nws yog ib leeg-stranded RNA ib ntus uas yog ntxiv rau DNA ntu ntawm cov noob. Nws muaj ob qho tib si coding thiab tsis-coding sequences. Feem ntau ntawm pre-mRNA muaj xws li heterogeneous nuclear RNA (hnRNA). Li no, nws dhau los ua ob peb kauj ruam ua ntej hloov mus rau hauv mRNA molecule. Cov kauj ruam tseem ceeb tshaj plaws yog kev tshem tawm cov kev cuam tshuam uas tsis qhia meej cov amino acids tsim nyog. Hauv lwm lo lus, nws yog kauj ruam hu ua pre-mRNA splicing, uas tshem tawm cov tsis-coding sequences (introns) los ntawm pre-mRNA thiab koom coding sequences ua ke.
Daim duab 01: Pre-mRNA
Thaum lub sijhawm ua haujlwm, qhov sib ntxiv ntawm stabilizing thiab signaling yam ntawm 5′ thiab 3′ kawg ntawm cov molecule tshwm sim. Ib lub hau yog ntxiv rau 5 'kawg thaum lub poly-A tail ntxiv rau 3' kawg. Ob leeg 5 'cap thiab 3' poly-A tail tiv thaiv mRNA molecule los ntawm degradation.
mRNA yog dab tsi?
mRNA (mature messenger RNA) yog ib txoj hlua RNA ib ntus uas muaj cov ntaub ntawv caj ces ntawm cov noob los tsim cov protein. Ua ntej. mRNA ua mRNA tom qab ua tiav. Li no, nws tsuas muaj cov exons lossis coding sequences ntawm cov noob. Thaum ua tiav, mRNA taug kev deb ntawm lub nucleus mus rau cytoplasm. Hauv cytoplasm, ribosomes nyeem lub hauv paus ua ntu zus ntawm mRNA thiab nrhiav cov amino acids sib xws. Thaum cov amino acid ua ntu zus, nws nkag mus folding thiab dhau los ua cov protein ua haujlwm.
Daim duab 02: mRNA
Kev ua thiab thauj ntawm mRNA txawv ntawm eukaryotes thiab prokaryotes. Eukaryotic mRNA yuav tsum tau ua ntau yam thiab thauj thaum prokaryotic mRNA tsis. Prokaryotic mRNA synthesis tshwm sim nyob rau hauv lub cytoplasm nws tus kheej, thiab ib zaug ua, nws yog tam sim ntawd npaj mus undergo kev txhais lus tsis ua.
Dab tsi yog qhov zoo sib xws ntawm pre-mRNA thiab mRNA?
- Pre-mRNA hloov mus rau mRNA tom qab ua tiav.
- Ob leeg ua ntej mRNA thiab mRNA yog cov khoom lag luam ntawm cov noob hloov pauv.
- Lawv yog ib leeg-stranded RNA.
- Ob leeg yog synthesized nyob rau hauv lub cell nucleus.
- Lawv muaj nyob rau hauv eukaryotic hlwb.
- Ob leeg muaj qhov sib txuas ua ke ntawm DNA ib ntus ntawm cov noob.
Qhov txawv ntawm pre-mRNA thiab mRNA yog dab tsi?
Pre-mRNA yog cov ntawv sau tseem ceeb uas muaj ob qho tib si coding thiab tsis-coding sequences. mRNA yog tus tub txib paub tab RNA uas tsuas muaj cov txheej txheem coding ntawm cov noob. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm pre-mRNA thiab mRNA. Pre-mRNA yog ua raws li ob peb kauj ruam ua, thaum mRNA yog cov khoom uas tshwm sim los ntawm kev ua. Ntxiv mus, pre-mRNA tsis mus rau cytoplasm thaum mRNA mus rau cytoplasm thiaj li tsim tau cov protein.
Cov ntaub ntawv hauv qab no-daim duab tabulates ntau qhov sib txawv ntawm pre-mRNA thiab mRNA.
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Qhov sib txawv ntawm pre-mRNA thiab mRNA hauv Tabular Form
Summary – pre-mRNA vs mRNA
Pre-mRNA yog cov khoom tam sim ntawm kev hloov pauv ntawm cov noob. Nws muaj coding thiab non-coding sequences ntawm ib tug noob. Ntau cov txheej txheem ua kom yooj yim rau kev hloov pauv ntawm pre-mRNA rau hauv mRNA. mRNA yog qhov tseeb RNA ib ntus uas muaj cov txheej txheem coding ntawm cov noob. Nws muaj cov kab mob caj ces ntawm cov protein. Ob leeg pre-mRNA thiab mRNA yog ib leeg-stranded RNA sequences uas muaj ib tug ua raws li ib tug ntawm cov DNA strands ntawm ib tug noob. Yog li, qhov no qhia txog qhov sib txawv ntawm pre-mRNA thiab mRNA.
