Cov plasma membrane yog lipid bilayer nrog cov proteins, ion channels thiab receptor molecules ua rau nws tuab. Qhov no yog ib tug neeg kho tshuab barrier uas cais lub cytoplasm ntawm lub cell los ntawm lub pericellular qhov chaw, nyob rau tib lub sij hawm tsuas yog kev twb kev txuas nrog rau sab nraud ib puag ncig. Yog li ntawd, plasmolemma yog ib qho ntawm cov qauv tseem ceeb tshaj plaws ntawm cov cell, thiab nws txoj haujlwm tso cai rau nws muaj nyob thiab cuam tshuam nrog lwm pawg ntawm tes.
Txheej txheem cej luam ntawm lub luag haujlwm ntawm cytolemma
Cov ntshav plasma nyob rau hauv daim ntawv uas nws muaj nyob rau hauv ib tug tsiaj cell yog yam ntxwv ntawm ntau yam kab mob los ntawm txawv lub nceeg vaj. Cov kab mob thiab cov kab mob protozoa, uas nws cov kab mob tau sawv cev los ntawm ib lub xov tooj ntawm tes, muaj cytoplasmic membrane. Thiab tsiaj, fungi thiab nroj tsuag raws li multicellular kab mob tsis tau poob nws nyob rau hauv tus txheej txheem ntawm evolution. Txawm li cas los xij, nyob rau hauv ntau lub nceeg vaj ntawm cov kab mob nyobcytolemma yog qhov txawv me ntsis, txawm hais tias nws txoj haujlwm tseem zoo ib yam. Lawv tuaj yeem muab faib ua peb pawg: delimiting, thauj thiab kev sib txuas lus.
Pab pawg ntawm delimiting lub luag haujlwm suav nrog kev tiv thaiv txhua yam ntawm tes, tswj nws cov duab, tiv thaiv los ntawm ib puag ncig extracellular. Lub membrane plays ib pab pawg neeg ntawm kev thauj mus los vim muaj cov proteins tshwj xeeb, ion channels thiab nqa ntawm qee yam khoom. Cov haujlwm sib txuas lus ntawm cytolemma suav nrog kev ua haujlwm receptor. Nyob rau saum npoo ntawm daim nyias nyias muaj ib txheej ntawm receptor complexes, uas lub cell koom nyob rau hauv lub mechanisms ntawm humoral ntaub ntawv hloov lwm lub tsev. Txawm li cas los xij, nws tseem ceeb heev uas cov plasmolemma nyob ib puag ncig tsis yog ntawm lub cell xwb, tab sis kuj qee qhov ntawm nws cov membrane organelles. Nyob rau hauv lawv, nws plays tib lub luag hauj lwm raws li nyob rau hauv cov ntaub ntawv ntawm tag nrho cov cell.
Barrier muaj nuj nqi
Txoj haujlwm ntawm lub plasma membrane muaj ntau yam. Nws tiv thaiv ib puag ncig sab hauv ntawm lub xov tooj ntawm tes nrog cov ntsiab lus ntawm cov tshuaj los ntawm nws qhov kev hloov pauv. Diffusion tshwm sim hauv cov kev daws teeb meem, uas yog, nws tus kheej sib npaug ntawm kev sib npaug ntawm cov xov xwm nrog cov ntsiab lus sib txawv ntawm qee yam khoom hauv lawv. Lub plasmalemma tsuas yog thaiv kev sib kis los ntawm kev tiv thaiv cov kua thiab ions hauv txhua qhov kev taw qhia. Yog li, daim nyias nyias txwv cov cytoplasm nrog qee qhov kev xav ntawm electrolytes los ntawm ib puag ncig pericellular.
Qhov thib ob tshwm sim ntawm kev ua haujlwm ntawm cov kab mob plasma yog kev tiv thaiv los ntawm cov kua qaub thiab muaj zog alkaline ib puag ncig. Plasma membrane uayog li ntawd cov hydrophobic kawg ntawm cov lipid molecules yog tig rau sab nraud. Yog li ntawd, nws feem ntau paub qhov txawv ntawm qhov chaw nruab nrab ntawm lub cev thiab cov khoom siv sab nraud nrog cov pH sib txawv. Nws yog qhov tseem ceeb rau lub neej ntawm tes.
Kev ua haujlwm ntawm organelle membranes
Qhov cuam tshuam kev ua haujlwm ntawm cov plasma membrane kuj txawv vim lawv nyob ntawm nws qhov chaw. Tshwj xeeb, karyolemma, uas yog, lipid bilayer ntawm lub nucleus, tiv thaiv nws los ntawm kev puas tsuaj rau cov khoom siv hluav taws xob thiab cais lub ntiaj teb ib puag ncig ntawm cytoplasmic. Ntxiv mus, nws ntseeg tau tias karyolemma yog inextricably txuas nrog daim nyias nyias ntawm endoplasmic reticulum. Yog li ntawd, tag nrho cov txheej txheem yog suav hais tias yog ib qho chaw cia khoom ntawm cov ntaub ntawv keeb kwm yav dhau los, cov txheej txheem protein synthesizing thiab pawg ntawm kev hloov pauv tom qab kev hloov pauv ntawm cov protein molecules. Lub membrane ntawm endoplasmic reticulum yog tsim nyog los tswj cov duab ntawm intracellular thauj channel los ntawm cov protein, lipid thiab carbohydrate molecules txav.
Cov mitochondrial membrane tiv thaiv mitochondria, thaum lub plastid membrane tiv thaiv chloroplasts. Lub lysosomal daim nyias nyias kuj ua lub luag haujlwm ntawm kev thaiv: sab hauv lysosome muaj qhov hnyav pH ib puag ncig thiab cov pa oxygen reactive uas tuaj yeem ua rau cov qauv hauv lub cell puas yog tias lawv nkag mus rau ntawd. Lub membrane, ntawm qhov tod tes, yog ib qho kev txwv thoob ntiaj teb, ob qho tib si tso cai rau lysosomes " zom" cov khoom thiab txwv qhov chaw ntawm kev ua ntawm enzymes.
Kev ua haujlwm ntawm cov plasma membrane
Kev ua haujlwm ntawm cov plasma membrane kuj yog qhov sib txawv. Ua ntej, cov plasma membrane txhawb nqacellular daim ntawv. Qhov thib ob, nws txwv qhov deformability ntawm tes, tab sis tsis tiv thaiv kev hloov pauv hauv cov duab thiab fluidity. Nyob rau hauv rooj plaub no, lub zog ntawm daim nyias nyias kuj ua tau. Qhov no tshwm sim vim yog tsim ntawm phab ntsa ntawm tes los ntawm protists, kab mob, nroj tsuag thiab fungi. Hauv cov tsiaj, suav nrog tib neeg hom, phab ntsa ntawm tes yog qhov yooj yim tshaj plaws thiab tsuas yog sawv cev los ntawm glycocalyx.
Hauv cov kab mob nws yog glycoprotein, hauv cov nroj tsuag nws yog cellulose, hauv fungi nws yog chitinous. Diatoms txawm koom nrog silica (silicon oxide) rau hauv lawv cov phab ntsa ntawm tes, uas ua rau kom muaj zog thiab ua haujlwm ntawm lub cell. Thiab txhua lub cev xav tau ib phab ntsa ntawm tes rau qhov no. Thiab plasmolemma nws tus kheej muaj zog qis dua li txheej ntawm proteoglycans, cellulose lossis chitin. Tsis muaj qhov tsis ntseeg tias cytolemma ua lub luag haujlwm kho tshuab.
Tsis tas li, cov haujlwm ua haujlwm ntawm cov plasma membrane tso cai rau mitochondria, chloroplasts, lysosomes, nucleus thiab endoplasmic reticulum ua haujlwm hauv cell thiab tiv thaiv lawv tus kheej los ntawm kev puas tsuaj. Qhov no yog ib qho zoo rau txhua lub cell uas muaj cov membrane organelles. Tsis tas li ntawd, cov plasma membrane muaj cytoplasmic outgrowths, los ntawm kev sib cuag intercellular yog tsim. Qhov no yog ib qho piv txwv ntawm kev siv lub tshuab ua haujlwm ntawm plasma membrane. Lub luag haujlwm tiv thaiv ntawm daim nyias nyias kuj tau lees paub los ntawm lub ntuj tsis kam thiab fluidity ntawm lipid bilayer.
Kev sib txuas lus ntawm cytoplasmic membrane
Kev thauj mus los thiab kev txais tos yog cov haujlwm sib txuas lus. Cov noob qho tib si zoo yog cov yam ntxwv ntawm cov plasma membrane thiab karyolemma. Lub membrane ntawm organelles tsis yog ib txwm muaj receptors los yog permeated nrog thauj raws, tab sis lub karyolemma thiab cytolemma muaj cov formations. Nws yog los ntawm lawv uas cov kev sib txuas lus tau siv.
Kev thauj mus los yog siv los ntawm ob txoj kev ua tau: nrog kev siv hluav taws xob, uas yog, hauv txoj kev nquag, thiab tsis muaj kev siv nyiaj, los ntawm kev nthuav dav yooj yim. Txawm li cas los xij, lub cell kuj tuaj yeem thauj cov khoom los ntawm phagocytosis lossis pinocytosis. Qhov no yog pom tau los ntawm kev ntes cov huab ntawm cov kua lossis cov khoom siv los ntawm kev tawm ntawm cytoplasm. Tom qab ntawd lub xovtooj ntawm tes, zoo li nrog nws txhais tes, ntes ib qho me me los yog cov kua dej, kos rau hauv thiab tsim ib txheej cytoplasmic nyob ib ncig ntawm nws.
Kev thauj mus los, nthuav dav
Kev thauj mus los yog ib qho piv txwv ntawm kev xaiv cov khoom siv electrolytes lossis cov khoom noj. Los ntawm cov kab tshwj xeeb uas sawv cev los ntawm cov protein molecules uas muaj ntau lub subunits, ib yam khoom los yog cov hydrated ion nkag mus rau hauv cytoplasm. Ions hloov qhov muaj peev xwm, thiab cov khoom noj khoom haus tau tsim rau hauv cov kab mob metabolic. Thiab tag nrho cov haujlwm no ntawm cov plasma membrane hauv lub cell nquag pab txhawb rau nws txoj kev loj hlob thiab kev loj hlob.
Lipid solubility
Cov hlwb sib txawv xws li paj hlwb, endocrine lossis cov leeg nqaij siv cov ion channel los tsim kom muaj peev xwm so thiab ua haujlwm. Nws yog tsim los ntawm osmotic thiab electrochemical sib txawv, thiab cov ntaub so ntswg muaj peev xwm mus cog lus,tsim los yog ua ib qho impulse, teb rau cov teeb liab lossis xa lawv. Qhov no yog ib qho tseem ceeb mechanism rau kev sib pauv ntawm cov ntaub ntawv ntawm cov hlwb, uas underlies lub paj hlwb tswj kev ua hauj lwm ntawm tag nrho cov kab mob. Cov haujlwm no ntawm plasma membrane ntawm cov tsiaj cell muab cov kev cai ntawm kev ua haujlwm tseem ceeb, kev tiv thaiv thiab txav ntawm tag nrho cov kab mob.
Qee yam tshuaj tuaj yeem nkag mus rau hauv daim nyias nyias, tab sis qhov no tsuas yog siv rau cov molecules ntawm lipophilic fat-soluble molecules. Lawv tsuas yaj nyob rau hauv lub bilayer ntawm daim nyias nyias, yooj yim nkag mus rau hauv lub cytoplasm. Qhov kev thauj mus los no yog qhov raug rau cov tshuaj hormones steroid. Thiab cov tshuaj hormones ntawm cov qauv peptide tsis tuaj yeem nkag mus rau hauv daim nyias nyias, txawm hais tias lawv kuj xa cov ntaub ntawv mus rau lub cell. Qhov no ua tiav vim muaj cov receptor (ib qho) molecules nyob rau saum npoo ntawm plasmalemma. Cov txheej txheem biochemical cuam tshuam ntawm cov teeb liab xa mus rau lub nucleus, ua ke nrog cov txheej txheem ntawm kev nkag mus ncaj qha ntawm cov tshuaj lipid los ntawm daim nyias nyias, ua ib qho yooj yim ntawm kev tswj hwm kev lom zem. Thiab tag nrho cov haujlwm no ntawm cov ntsiab lus tseem ceeb ntawm cov plasma membrane yog xav tau tsis yog los ntawm ib lub xovtooj, tab sis los ntawm tag nrho cov kabmob.
Cov lus ua haujlwm ntawm cytoplasmic membrane
Txoj kev pom kev tshaj plaws los qhia txog kev ua haujlwm ntawm cov plasma membrane yog lub rooj uas qhia txog nws lub luag haujlwm lom rau lub cell tag nrho.
| qauv | Function | Lub luag haujlwm lom neeg |
| Cytoplasmic membrane nyob rau hauv daim ntawv ntawm lipid bilayer nrogOutwardly nyob hydrophobic kawg, nruab nrog receptor complexes ntawm ib qho thiab nto proteins | Mechanical | Txhim kho cellular zoo, tiv thaiv kev cuam tshuam ntawm cov neeg kho tshuab subthreshold, khaws cia cellular kev ncaj ncees |
| Kev thauj mus los | Kev thauj cov kua dej, cov khoom siv, cov macromolecules thiab hydrated ions rau hauv lub cell nrog lossis tsis muaj kev siv hluav taws xob | |
| Receptor | Nws muaj receptor molecules ntawm nws qhov chaw uas ua haujlwm xa cov ntaub ntawv mus rau lub nucleus | |
| Adhesive | Vim yog qhov protrusions ntawm cytoplasm, cov hlwb nyob sib ze tsim kev sib cuag nrog ib leeg | |
| Electrogenic | Muab cov xwm txheej rau kev tsim cov peev txheej ua haujlwm thiab so lub peev xwm ntawm cov ntaub so ntswg txaus ntshai |
Cov lus no qhia meej meej tias lub plasma membrane ua haujlwm li cas. Txawm li cas los xij, tsuas yog cov cell membrane, uas yog, lipid bilayer nyob ib puag ncig tag nrho ntawm tes, ua lub luag haujlwm no. Nyob rau hauv nws muaj organelles, uas kuj muaj daim nyias nyias. Lawv lub luag haujlwm yuav tsum tau piav qhia.
Kev ua haujlwm ntawm plasma membrane: tswvyim
Cov organelles hauv qab no txawv ntawm qhov muaj cov membranes hauv lub cell: nucleus, ntxhib thiab du endoplasmic reticulum, Golgi complex, mitochondria, chloroplasts, lysosomes. Hauv txhua qhovcov organelles, daim nyias nyias plays lub luag hauj lwm tseem ceeb. Koj tuaj yeem xav txog nws siv qhov piv txwv ntawm cov phiaj xwm tabular.
| Organella thiab membrane | Function | Lub luag haujlwm lom neeg |
| Nucleus, Nucleus membrane | Mechanical | Kev ua haujlwm ntawm cov plasma membrane ntawm cytoplasm ntawm lub nucleus tso cai rau nws tswj nws cov duab, tiv thaiv qhov tshwm sim ntawm kev puas tsuaj |
| Txoj Kev | YKev sib cais ntawm nucleoplasm thiab cytoplasm | |
| Kev thauj mus los | Nws muaj kev thauj cov pores rau kev tawm ntawm ribosomes thiab xa xov RNA los ntawm cov nucleus thiab nkag mus rau cov as-ham, amino acids thiab nitrogenous bases rau sab hauv | |
| Y Mitochondrion, mitochondrial membrane | Mechanical | Txhim kho cov duab ntawm mitochondria, tiv thaiv kev puas tsuaj |
| Kev thauj mus los | Ions thiab lub zog substrates raug xa mus los ntawm daim nyias nyias | |
| Electrogenic | Muab kev tsim cov peev txheej transmembrane, uas yog lub hauv paus ntawm kev tsim hluav taws xob hauv cell | |
| Chloroplast, plastid membrane | Mechanical | Txhawb cov duab ntawm plastids, tiv thaiv lawv cov khoom puas tsuaj |
| Kev thauj mus los | Kev thauj khoom | |
| YEndoplasmic reticulum, daim nyias nyias ntawm lub network | Mechanical and Environment-forming | Muab lub xub ntiag ntawm kab noj hniav uas cov txheej txheem ntawm cov protein synthesis thiab lawv cov kev hloov pauv tom qab hloov pauv |
| Golgi apparatus, membrane ntawm vesicles thiab cisterns | Mechanical and Environment-forming | Role saib saum toj |
| Lysosomes, lysosomal membrane |
Mechanical Txoj Kev |
tuav cov duab ntawm lysosome, tiv thaiv kev puas tsuaj thiab tso cov enzymes rau hauv cytoplasm, txwv tsis pub nws los ntawm lytic complexes |
Tsiaj cell membranes
Cov no yog cov haujlwm ntawm cov ntshav plasma hauv lub cell, uas nws ua lub luag haujlwm tseem ceeb rau txhua lub cev. Ntxiv mus, ntau lub luag haujlwm yuav tsum tau muab tso ua ke rau hauv ib qho - rau hauv ib qho kev tiv thaiv. Tshwj xeeb, cov khoom thaiv thiab cov tshuab ua haujlwm tau muab tso ua ke rau hauv ib qho kev tiv thaiv. Ntxiv mus, cov dej num ntawm cov plasma membrane nyob rau hauv cov nroj tsuag cell yuav luag zoo tib yam rau cov tsiaj thiab kab mob cell.
Tus tsiaj cell yog qhov nyuaj tshaj plaws thiab sib txawv heev. Ntau qhov sib xyaw ua ke, semi-integral thiab cov protein ntau nyob ntawm no. Feem ntau, nyob rau hauv multicellular kab mob, lub membrane qauv yog ib txwm complex tshaj nyob rau hauv unicellular sawv daws yuav. Thiab dab tsi ua haujlwm ntawm plasma membrane ntawm ib lub xovtooj ntawm tes ua haujlwm txiav txim siab seb nws puas yuav raug cais raws li epithelial, txuas lossisdaim ntaub so ntswg.
