Kev txhais hauv biology yog txheej txheem ntau theem ntawm kev nyeem cov ntaub ntawv los ntawm DNA, uas yog ib feem ntawm cov protein biosynthesis hauv lub cell. Nucleic acid yog tus nqa ntawm cov ntaub ntawv caj ces hauv lub cev, yog li nws yog ib qho tseem ceeb uas yuav tsum ua kom raug txiav txim siab thiab hloov mus rau lwm cov txheej txheem ntawm tes kom txuas ntxiv ntawm peptides.
Definition of "transcription in biology"
Protein synthesis yog ib txoj hauv kev tseem ceeb hauv txhua lub cell ntawm lub cev. Yog tias tsis muaj kev tsim peptide molecules, nws tsis tuaj yeem tswj hwm lub neej ib txwm ua haujlwm, vim tias cov organic tebchaw koom nrog hauv txhua qhov txheej txheem metabolic, yog cov txheej txheem ntawm ntau cov ntaub so ntswg thiab cov kabmob, ua lub cim qhia, tswj hwm thiab tiv thaiv lub luag haujlwm hauv lub cev.
txheej txheem los ntawm cov protein biosynthesis pib yog kev sau ntawv. Biology luv luv muab faib ua peb theem:
- Kev pib.
- Elongation (kev loj hlob ntawm RNA saw).
- Tawm.
Kev txhais lus hauv biology yog tag nrho ntawm cov tshuaj tiv thaiv ib ntus, vim tias cov molecules tau tsim los ntawm DNA qauvRNA. Ntxiv mus, tsis tsuas yog cov ntaub ntawv ribonucleic acids tsim nyob rau hauv txoj kev no, tab sis kuj thauj, ribosomal, me me nuclear thiab lwm yam.
Zoo li cov txheej txheem biochemical, kev sau ntawv yog nyob ntawm ntau yam. Ua ntej tshaj plaws, cov no yog cov enzymes sib txawv ntawm prokaryotes thiab eukaryotes. Cov protein tshwj xeeb no pab pib thiab ua tiav cov kev hloov pauv kom raug, uas yog qhov tseem ceeb rau cov khoom noj muaj txiaj ntsig zoo.
Kev txhais ntawm prokaryotes
Txij li kev sau ntawv hauv biology yog kev sib txuas ntawm RNA ntawm DNA qauv, lub ntsiab enzyme hauv cov txheej txheem no yog DNA-dependent RNA polymerase. Hauv cov kab mob, tsuas muaj ib hom polymerase rau tag nrho cov molecules ntawm ribonucleic acid.
RNA polymerase, raws li lub hauv paus ntsiab lus ntawm complementarity, ua tiav RNA saw siv tus qauv DNA saw. Cov enzyme no muaj ob lub β-subunits, ib qho α-subunit thiab ib qho σ-subunit. Thawj ob yam ua haujlwm ntawm kev tsim lub cev ntawm cov enzyme, thiab ob qho ntxiv yog lub luag haujlwm khaws cov enzyme ntawm DNA molecule thiab lees paub qhov txhawb nqa ib feem ntawm deoxyribonucleic acid, raws li.
Los ntawm txoj kev, qhov zoo tshaj plaws sigma yog ib qho ntawm cov cim qhia los ntawm qhov no lossis cov noob tau lees paub. Piv txwv li, tsab ntawv Latin σ nrog Performance index N txhais tau hais tias qhov RNA polymerase paub cov noob uas tig rau thaum tsis muaj nitrogen hauv ib puag ncig.
Kev hloov pauv hauv eukaryotes
Tsis zoo li cov kab mob,tsiaj thiab cov nroj tsuag transcription yog me ntsis nyuab dua. Ua ntej, hauv txhua lub cell tsis muaj ib qho, tab sis ntau li peb hom RNA polymerases sib txawv. Ntawm lawv:
- RNA polymerase I. Nws yog lub luag haujlwm rau kev hloov pauv ntawm ribosomal RNA noob (nrog rau kev zam ntawm 5S RNA subunits ntawm ribosome).
- RNA polymerase II. Nws txoj hauj lwm yog los tsim cov ntaub ntawv ib txwm muaj (matrix) ribonucleic acids, uas txuas ntxiv rau kev txhais lus.
- RNA polymerase III. Lub luag haujlwm ntawm hom polymerase no yog los ua ke thauj ribonucleic acids, nrog rau 5S-ribosomal RNA.
Thib ob, rau kev txhawb nqa kev lees paub hauv cov hlwb eukaryotic, nws tsis txaus kom muaj cov polymerase nkaus xwb. Kev pib sau ntawv kuj tseem muaj cov peptides tshwj xeeb hu ua TF proteins. Tsuas yog nrog lawv cov kev pab tuaj yeem RNA polymerase zaum ntawm DNA thiab pib cov synthesis ntawm ribonucleic acid molecule.
Tus nqi sau npe
RNA molecule, uas yog tsim los ntawm DNA qauv, tom qab ntawd koom nrog cov ribosomes, qhov twg cov ntaub ntawv tau nyeem los ntawm nws thiab cov protein yog synthesized. Cov txheej txheem ntawm kev tsim peptide tseem ceeb heev rau lub cell, vim hais tias Yog tsis muaj cov organic tebchaw, lub neej ib txwm ua tsis tau: lawv yog, ua ntej ntawm tag nrho cov, lub hauv paus rau cov enzymes tseem ceeb tshaj plaws ntawm tag nrho cov tshuaj biochemical.
Kev txhais lus hauv biology kuj yog qhov chaw ntawm rRNA, uas yog ib feem ntawm ribosomes, nrog rau tRNA, uas koom nrog kev hloov ntawm cov amino acids thaum lub sij hawm kev txhais lus rau cov uas tsis yog-membrane.cov qauv. snRNAs (me me nuclei) kuj tuaj yeem ua ke, ua haujlwm ntawm kev sib txuas tag nrho RNA molecules.
Zoo kawg
Kev txhais lus thiab kev txhais lus hauv biology ua lub luag haujlwm tseem ceeb hauv kev tsim cov protein molecules. Cov txheej txheem no yog cov ntsiab lus tseem ceeb ntawm lub hauv paus dogma ntawm molecular biology, uas hais tias RNA yog synthesized ntawm DNA matrix, thiab RNA, nyob rau hauv lem, yog lub hauv paus rau qhov pib ntawm kev tsim cov protein molecules.
Yog tsis muaj kev sau, nws yuav tsis tuaj yeem nyeem cov ntaub ntawv uas tau muab tso rau hauv triplets ntawm deoxyribonucleic acid. Qhov no ib zaug ntxiv ua pov thawj qhov tseem ceeb ntawm cov txheej txheem ntawm qib biological. Txhua lub xovtooj ntawm tes, tsis hais nws prokaryotic lossis eukaryotic, yuav tsum tau lossi tsim cov protein molecules tshiab thiab tshiab uas xav tau tam sim no los tswj lub neej. Yog li, kev sau ntawv hauv biology yog theem tseem ceeb hauv kev ua haujlwm ntawm txhua tus neeg ntawm lub cev.
