Lub xovtooj ntawm txhua yam kabmob yog ib lub koomhaum loj rau kev tsim cov tshuaj. Qhov no tshwm sim tshwm sim nyob rau hauv biosynthesis ntawm lipids, nucleic acids, carbohydrates thiab, ntawm chav kawm, proteins. Proteins ua lub luag haujlwm loj hauv lub neej ntawm tes, vim lawv ua haujlwm ntau yam: enzymatic, teeb liab, qauv, tiv thaiv, thiab lwm yam.
YProtein biosynthesis: piav qhia txog txheej txheem
Kev tsim cov protein molecules yog txheej txheem ntau theem uas tshwm sim nyob rau hauv qhov kev txiav txim ntawm ntau cov enzymes thiab nyob rau hauv muaj qee yam qauv.
Synthesis ntawm ib qho protein pib hauv lub nucleus. Cov ntaub ntawv hais txog cov qauv ntawm cov molecule yog sau rau hauv DNA ntawm lub cell, los ntawm qhov uas nws tau nyeem. Yuav luag txhua cov noob hauv cov kab mob hauv lub cev encodes ib qho, tshwj xeeb protein molecule.
Lub luag haujlwm ntawm cytoplasm hauv cov protein biosynthesis yog dab tsi? Qhov tseeb yog tias cytoplasm ntawm tes yog "pas dej" rau cov monomers ntawm cov tshuaj complex, nrog rau cov qauv uas yog lub luag haujlwm rau cov txheej txheem ntawm cov protein synthesis. Tsis tas li ntawd, ib puag ncig sab hauv ntawm tes muaj qhov acidity tas li thiabCov ntsiab lus ion, uas ua lub luag haujlwm tseem ceeb hauv cov tshuaj biochemical.
Protein biosynthesis tshwm sim nyob rau hauv ob theem: transcription thiab translation.
Kev txhais lus
theem no pib nyob rau hauv lub nucleus ntawm lub cell. Ntawm no lub luag haujlwm tseem ceeb yog ua los ntawm cov nucleic acids xws li DNA thiab RNA (deoxy- thiab ribonucleic acids). Hauv eukaryotes, chav tsev ntawm kev sau ntawv yog cov ntawv sau, thaum nyob hauv prokaryotes, lub koom haum DNA no hu ua operon. Qhov sib txawv ntawm kev sau ntawv hauv prokaryotes thiab eukaryotes yog tias ib qho operon yog ib feem ntawm DNA molecule uas encodes ntau cov protein molecules, thaum cov ntaub ntawv sau tseg tsuas yog ib qho protein ntau.
Lub luag haujlwm tseem ceeb ntawm lub xovtooj ntawm theem ntawm kev hloov pauv yog kev sib txuas ntawm tus xa xov RNA (mRNA) ntawm DNA qauv. Ua li no, ib qho enzyme xws li RNA polymerase nkag mus rau hauv lub nucleus. Nws koom nrog hauv kev sib txuas ntawm mRNA molecule tshiab, uas yog ntxiv rau qhov chaw deoxyribonucleic acid.
Rau qhov kev hloov pauv tau zoo, qhov muaj cov ntsiab lus hloov pauv, uas tseem raug hu ua TF-1, TF-2, TF-3, yog qhov tsim nyog. Cov txheej txheem protein ntau no koom nrog kev sib txuas ntawm RNA polymerase nrog tus txhawb nqa ntawm DNA molecule.
Qhov kev sib txuas ntawm mRNA txuas ntxiv mus txog thaum cov polymerase mus txog thaj tsam kawg ntawm cov ntawv teev lus, uas yog hu ua terminator.
Tus neeg teb xov tooj, raws li lwm qhov chaw ua haujlwm ntawm cov ntawv sau tseg, yog lub luag haujlwm rau inhibiting transcription lossis, conversely, rau accelerating txoj hauj lwm ntawm RNA polymerase. Lub luag haujlwm rauKev tswj hwm ntawm kev ua haujlwm ntawm cov enzymes tshwj xeeb proteins-inhibitors lossis proteins-activators, feem.
Tshaj tawm
Tom qab mRNA tau tsim nyob rau hauv lub cell nucleus, nws nkag mus rau cytoplasm. Txhawm rau teb cov lus nug txog lub luag haujlwm ntawm cytoplasm hauv cov protein biosynthesis, nws tsim nyog soj ntsuam kom ntxaws ntxiv txog txoj hmoo ntawm nucleic acid molecule nyob rau theem txhais.
Kev txhais lus tshwm sim hauv peb theem: pib, elongation thiab txiav tawm.
Ua ntej, mRNA yuav tsum txuas rau ribosomes. Ribosomes yog cov qauv me me uas tsis yog-membrane ntawm tes, uas muaj ob lub subunits: me thiab loj. Ua ntej, cov ribonucleic acid txuas mus rau lub subunit me me, thiab tom qab ntawd lub subunit loj kaw tag nrho cov kev txhais lus kom lub mRNA nyob rau hauv lub ribosome. Qhov tseeb, qhov no yog qhov kawg ntawm theem pib.
Lub luag haujlwm ntawm cytoplasm hauv cov protein biosynthesis yog dab tsi? Ua ntej ntawm tag nrho cov, nws yog ib qhov chaw ntawm cov amino acids - lub ntsiab monomers ntawm tej proteins. Nyob rau theem ntawm elongation, maj mam tsim ntawm cov saw hlau polypeptide tshwm sim, pib nrog qhov pib codon methionine, uas txuas ntxiv cov amino acids. Lub codon nyob rau hauv cov ntaub ntawv no yog triplet ntawm mRNA nucleotides uas codes rau ib tug amino acid.
Nyob rau theem no, lwm hom ribonucleic acid txuas nrog ua haujlwm - hloov RNA, lossis tRNA. Lawv yog lub luag haujlwm xa cov amino acids rau mRNA-ribosome complex los ntawm kev tsim cov aminoacyl-tRNA complex. tRNA kev lees paub tshwm sim los ntawm kev sib ntxivKev sib cuam tshuam ntawm anticodon ntawm no molecule nrog cov codon ntawm mRNA. Yog li, cov amino acid raug xa mus rau ribosome thiab txuas mus rau cov saw hlau polypeptide synthesized.
Kev txiav tawm ntawm cov txheej txheem txhais lus tshwm sim thaum mRNA mus txog ntu ntu codon. Cov codons nqa cov ntaub ntawv hais txog qhov kawg ntawm peptide synthesis, tom qab ntawd cov ribosome-RNA complex raug rhuav tshem, thiab cov qauv tseem ceeb ntawm cov protein tshiab nkag mus rau cytoplasm rau kev hloov tshuaj lom neeg ntxiv.
Tshwj xeeb protein pib yam tseem ceeb IF thiab elongation yam EF koom nrog hauv txheej txheem txhais lus. Lawv muaj ntau hom, thiab lawv txoj haujlwm yog los xyuas kom meej qhov kev sib txuas ntawm RNA nrog ribosome subunits, nrog rau hauv kev sib txuas ntawm cov saw hlau polypeptide nws tus kheej ntawm theem elongation.
Lub luag haujlwm ntawm cytoplasm yog dab tsi hauv cov protein biosynthesis: luv luv txog cov khoom tseem ceeb ntawm biosynthesis
Tom qab mRNA tawm ntawm cov nucleus mus rau hauv ib puag ncig sab hauv ntawm lub xovtooj, cov molecule yuav tsum tsim kom muaj kev hloov pauv ruaj khov. Dab tsi ntawm cov cytoplasm yuav tsum muaj nyob rau theem ntawm kev txhais lus?
1. Ribosomes.
2. Cov amino acids.
3. tRNA.
Amino acids - protein monomers
Rau qhov kev sib txuas ntawm cov saw hlau protein, muaj nyob hauv cytoplasm ntawm cov qauv ntawm peptide molecule - amino acids. Cov tshuaj uas tsis muaj molecular hnyav nyob rau hauv lawv muaj pes tsawg leeg muaj ib tug amino pawg NH2 thiab ib tug acid residue COOH. Lwm cov khoom ntawm cov molecule - lub radical - yog lub cim ntawm txhua tus neeg amino acid. Dab tsi yog lub luag haujlwm ntawm cytoplasm hauvCov protein biosynthesis?
AA tshwm sim hauv cov kev daws teeb meem hauv daim ntawv ntawm zwitterions, uas yog tib lub molecules uas pub lossis txais hydrogen protons. Yog li, cov amino pawg ntawm cov amino acids hloov mus rau hauv NH3 +, thiab pawg carbonyl rau hauv COO-.
Nyob rau hauv tag nrho, muaj 200 AAs nyob rau hauv cov xwm, uas tsuas yog 20 yog protein-forming. Ntawm lawv, muaj ib pab pawg ntawm cov amino acids tseem ceeb uas tsis tau tsim nyob rau hauv tib neeg lub cev thiab nkag mus rau hauv lub cell tsuas yog noj cov zaub mov, thiab cov amino acids tsis tseem ceeb uas lub cev tsim los ntawm nws tus kheej..
Txhua AAs yog encoded los ntawm qee cov codon uas sib haum rau peb mRNA nucleotides, thiab ib qho amino acid feem ntau tuaj yeem raug encoded los ntawm ntau qhov sib lawv liag ib zaug. Cov methionine codon hauv pro- thiab eukaryotes yog qhov pib, vim nws pib biosynthesis ntawm peptide saw. Stop codons include UAA, UGA and UAG nucleotide sequences.
ribosomes yog dab tsi?
Yuav ua li cas ribosomes lub luag haujlwm rau biosynthesis ntawm cov protein hauv lub cell thiab lub luag haujlwm ntawm cov qauv no yog dab tsi? Ua ntej ntawm tag nrho cov, cov no yog non-membrane formations, uas muaj ob subunits: loj thiab me. Lub luag haujlwm ntawm cov subunits no yog tuav lub mRNA molecule ntawm lawv.
Muaj cov chaw hauv ribosomes qhov twg mRNA codons nkag. Nyob rau hauv tag nrho, ob lub triplets no tuaj yeem haum ntawm lub subunit me thiab loj.
Ntau lub ribosomes tuaj yeem sib sau ua ke rau hauv ib qho loj polysome, vim tias tus nqi ntawm kev sib txuas ntawm cov saw peptide nce, thiab cov zis tuaj yeem tau txais tam sim ntawdntau daim ntawv luam ntawm cov protein. Nov yog lub luag haujlwm ntawm cytoplasm hauv cov protein biosynthesis.
Type of RNA
Ribonucleic acids ua lub luag haujlwm tseem ceeb ntawm txhua theem ntawm kev sau ntawv. Muaj peb pawg loj ntawm RNA: thauj, ribosomal thiab cov ntaub ntawv.
mRNAs koom nrog hauv kev hloov pauv cov ntaub ntawv hais txog kev muaj pes tsawg leeg ntawm cov saw peptide. tRNAs yog cov neeg kho kom haum xeeb hauv kev hloov cov amino acids rau ribosomes, uas yog ua tiav los ntawm kev tsim cov aminoacyl-tRNA complex. Kev sib txuas ntawm cov amino acid tsuas yog tshwm sim nrog kev sib txuas ntxiv ntawm anticodon ntawm kev hloov RNA nrog codon ntawm tus xa xov RNA.
rRNA koom nrog hauv kev tsim cov ribosomes. Lawv cov kab ke yog ib qho laj thawj vim li cas mRNA tuav ntawm cov subunits me thiab loj. Ribosomal RNAs yog tsim nyob rau hauv lub nucleoli.
Lub ntsiab lus ntawm cov proteins
Protein biosynthesis thiab nws qhov tseem ceeb rau lub cell yog colossal: feem ntau ntawm lub cev lub enzymes yog peptide xwm, ua tsaug rau cov proteins, tshuaj yog thauj los ntawm cell membranes.
Proteins kuj ua haujlwm zoo thaum lawv yog ib feem ntawm cov leeg nqaij, paj hlwb thiab lwm yam ntaub so ntswg. Lub luag haujlwm ntawm kev taw qhia yog xa cov ntaub ntawv hais txog cov txheej txheem tshwm sim, piv txwv li, thaum lub teeb poob rau ntawm retina. Protective proteins - immunoglobulins - yog lub hauv paus ntawm tib neeg lub cev tiv thaiv kab mob.
