Kev nkag siab txog lub hauv paus tseem ceeb ntawm kev muaj sia nyob ntawm lub neej yog tsis yooj yim sua yam tsis muaj kev nkag siab meej txog kev xa cov ntaub ntawv keeb kwm yav dhau los thiab nws qhov kev siv. Kev khaws cia ntawm lub cev cov noob yog paub los ntawm chromosomes, nyob rau hauv uas txawv seem ntawm DNA tau ntim, encoding thawj amino acid ib theem zuj zus ntawm ib tug tej yam proteins. Thiab kev siv cov ntaub ntawv ntawm caj ces thiab nws txoj kev sib kis los ntawm kev qub txeeg qub teg yog ua tiav los ntawm nws qhov kev luam tawm. Cov txheej txheem no hu ua "transcription". Nyob rau hauv biology, nws txhais tau tias nyeem cov cai ntawm ib tug noob seem thiab ua ke ib tug template rau protein biosynthesis raws li nws.
Molecular hauv paus ntawm kev hloov pauv
Kev txhais lus yog txheej txheem enzymatic uas yog ua ntej los ntawm "kev tshem tawm" ntawm DNA molecule thiab muab kev nkag mus rau kev nyeem cov noob tshwj xeeb. Tom qab ntawd nyob rau hauv ob-stranded DNA molecule rauHauv thawj ntu, hydrogen bonds ntawm nucleotides tawg rau 4 kadons. Txij lub sijhawm no, theem pib pib hauv biology pib, cuam tshuam nrog kev txuas ntawm DNA-dependent RNA polymerase rau DNA macropolymer.
Lub txiaj ntsig ntawm qhov pib yog qhov kev sib txuas ntawm qhov chaw pib ntawm tus xa xov RNA, thiab sai li sai tau thaum thawj cov nucleotide txuas nrog rau nws thiab kev hloov pauv ntawm DNA-raws li RNA polymerase tshwm sim, ib tus yuav tsum hais txog qhov pib. ntawm theem elongation. Nws cov ntsiab lus yog txo kom maj mam txav ntawm DNA-dependent RNA polymerase raws DNA molecule nyob rau hauv 3'-5' kev taw qhia, txiav cov DNA hydrogen bonds nyob rau hauv pem hauv ntej thiab rov qab los rau lawv tom qab, nrog rau kev txuas ntxiv nucleotide rau kev loj hlob. saw ntawm RNA template.
Enzyme DNA-dependent RNA polymerase catalyzes qhov sib ntxiv ntawm nucleotide rau RNA, thaum lwm lub tshuab enzyme yog lub luag haujlwm rau kev nyeem ntawv, sib cais hydrogen bonds thiab txo lawv. Tag nrho cov ntawm lawv nyob rau hauv qhov chaw uas transcription tshwm sim. Biology tso cai rau koj siv txoj kev sau npe atoms thiab lees paub qhov tseeb ntawm lawv qhov siab tshaj plaws hauv cov nuclei ntawm cov hlwb.
ncua sij hawm sau npe
Nyob rau hauv lub chaw soj nstuam, cov kws tshawb fawb ntawm pab pawg tshawb fawb "Human Genome" tau tswj hwm los tsim cov DNA molecule nws tus kheej thiab txuag cov noob caj noob ces hauv nws. Cov txheej txheem no tau siv ntau tshaj 2 xyoo caum, tsis suav nrog kev npaj ntev. Nws yog qhov nthuav sai npaum li cas cov txheej txheem no mus rau hauv lub cell nyob. Txoj kev tshawb fawb tseem ceebKev txhais lus thiab sau ntawv - molecular biology. Thiab txawm hais tias nws tseem tab tom ntsib teeb meem cuam tshuam nrog kev ua tsis tau zoo ntawm qhov pom ntawm cov txheej txheem no, muaj qee cov pov thawj hais txog lub sijhawm ntawm cov protein biosynthesis.
Tshwj xeeb, cov txheej txheem ntawm "tsis ntim khoom" cov ntaub ntawv caj ces tuaj yeem siv sijhawm 16-48 teev, thiab kev hloov pauv ntawm cov noob xav tau - txog 4-8 teev. Lub synthesis ntawm ib tug me me protein molecule raws li tus tub txib RNA yuav siv sij hawm txog 4-24 teev, tom qab uas cov theem ntawm nws "maturation" pib. Qhov no yog hais txog tus kheej-spontaneous ntim ntawm cov protein rau hauv ib nrab thiab tom qab ntawd mus rau hauv cov qauv tertiary. Yog hais tias cov protein yuav tsum tau hloov kho postsynthetic, ces cov txheej txheem no yuav siv li ib lub lim tiam los yog ntau tshaj.
Cellular cov qauv, qhov chaw sau thiab txhais lus tshwm sim, tab tom kawm ntau dua thiab nthuav dav hauv biology. Nyob rau tib lub sijhawm, nws tuaj yeem suav tias hauv eukaryotic hlwb nrog cov khoom siv caj ces loj, kev sib txuas ntawm cov tshuaj insulin yooj yim yuav siv li 16 teev. Hloov kho cov noob caj noob ces Escherichia coli tuaj yeem tsim cov molecule zoo li no hauv 4 teev. Nyob rau hauv cov ntaub ntawv ntawm loj proteins ntawm tertiary thiab quaternary qauv, cov txheej txheem ntawm lawv synthesis thiab zaum kawg tsim yuav siv sij hawm txog 2 lub lis piam.
Localization ntawm transcription enzymes
Cov txheej txheem xws li kev sau npe (hauv biology) tshwm sim hauv qhov chaw ncaj qha khaws cov ntaub ntawv keeb kwm yav dhau los. Nyob rau hauv eukaryotic hlwb, qhov no yog cell nucleus, thiab nyob rau hauv pre-nuclear life forms, nws yog lub cytoplasm. kab mob enzymethim rov qab transcriptase ua haujlwm nyob rau hauv lub nucleus ntawm cov kab mob. Nyob rau tib lub sij hawm, mitochondrial nucleic acids, uas yog ib txheej ntawm cov noob, kuj mus rau theem transcription. Hauv biology thiab noob caj noob ces, qhov xwm txheej ntawm cov txheej txheem no tseem tsis tau paub.
Tab sis qhov tseeb ntawm kev muaj tib neeg cov kab mob mitochondrial uas tau xeeb los ntawm cov xeeb leej xeeb ntxwv lees paub DNA rov ua dua, rau qhov kev hloov pauv yog qhov tsim nyog. Qhov no txhais tau hais tias cov txheej txheem zoo li no tuaj yeem tshwm sim hauv ntau lub cellular qauv: hauv eukaryotes, cov no yog mitochondria thiab cell nucleus, thiab hauv prokaryotes, hauv cytoplasm thiab plasmids.
Localization ntawm biosynthetic txheej txheem
Qhov chaw uas cov ntawv sau thiab txhais lus tshwm sim (hauv biology) txawv, vim tias kev sib xyaw ntawm cov protein molecules tsuas tuaj yeem tshwm sim hauv cell nucleus. Kev sib dhos ntawm cov qauv tseem ceeb tshwm sim ntawm lub ribosomal apparatus ntawm lub cell, uas yog feem ntau concentrated nyob rau hauv lub cytoplasm ntawm daim nyias nyias ntawm cov ntxhib endoplasmic reticulum.
Synthesis nyob rau hauv cov hlwb tsim heev, uas txawv los ntawm ib tug siab ntawm kev sib sau ua ke ntawm cov protein molecules tshiab, tshwm sim feem ntau ntawm polyribosomes. Tab sis nyob rau hauv cov kab mob thiab cov hlwb tshwj xeeb, biosynthesis tuaj yeem ua rau ntawm cov ribosomes sib txawv hauv cytoplasm. Viral lub cev tsis muaj lawv tus kheej cov cuab yeej hluavtaws thiab cov kab mob, thiab yog li siv cov qauv ntawm cov kab mob.
