Ikakhulukazi isakhiwo kanye umsebenzi cell ulwelwesi

Ngo-1972 wavalelwa phambili imfundiso yokuthi ulwelwesi kancane permeable esizungeze ingqamuzana futhi yenza imisebenzi eminingi ebalulekile, futhi isakhiwo kanye umsebenzi cell ulwelwesi kukhona nezindaba abalulekile mayelana ekusebenzeni kahle wonke amaseli asemzimbeni. Cell theory yathi chithi saka ekhulwini le-17, kanye kokusungulwa kwe-microscope. It is wathola ukuthi nezitshalo nezilwane kwezicubu yakhiwa kumaseli, kodwa ngenxa ongaphakeme isinqumo kudivayisi kwakungenakwenzeka ukubona izithiyo emhlabeni amaseli isilwane. Ekhulwini lama-20, uhlobo amakhemikhali ulwelwesi ukuthi ziphenywe kabanzi, kwatholakala ukuthi isisekelo yalo iyona lipids.

Sakhiwo umsebenzi cell ulwelwesi

I ulwelwesi cell izungeza cytoplasm ngamangqamuzana aphilayo, ngokwenyama uhlukanisa izingxenye intracellular kusukela imvelo bangaphandle. Fungus, ama-bacterium nezitshalo futhi babe iseli izindonga okuyinto ukuvikela kanye nokuzithuthukisa lezo ukuvimbela ukudlula molecule ezinkulu. Cell ulwelwesi nazo zinendima ethile e ukwakheka cytoskeleton futhi unamathele matrix extracellular nezinye izinhlayiya esibalulekile. Lokhu kuyadingeka ukuze uzigcine ndawonye akha izicubu izitho. Izici isakhiwo cell ulwelwesi zihlanganisa permeability. Umsebenzi oyinhloko ukuvikela. Ulwelwesi siqukethe ungqimba phospholipid ne amaprotheni esishunyekiwe. Le ngxenye ehilelekile izinqubo efana ne-cell adhesion, ion conductivity futhi izinhlelo okuwuphawu futhi ukhonza njengesisebenzi ebusweni obandayo izakhiwo eziningana extracellular, kuhlanganise odongeni glycocalyx futhi cytoskeleton yangaphakathi. Ulwelwesi futhi azigcina bezikhali amaseli, ukusebenza njengendlela lemifanekiso zikhethe. Kuyinto ngokukhetha permeable ukuba ion kanye amangqamuzana angokwemvelo futhi ilawula ukuhamba izinhlayiya.

izindlela eziphilayo ezihilela cell ulwelwesi

1. okusheshayo Passive: ezinye izinto (molecule encane, ion) ezifana carbon dioxide (CO2) nomoya-mpilo (O2), akwazi ukungena ulwelwesi plasma ngu okusheshayo. Izenzo bezinhlamvu njengesithiyo ukuze izakhi ezithile futhi ion, zingase bagxila nhlangothi zombili.

2. transmembrane iziteshi protein ne abathutha: izakhi ezifana glucose noma amino acid, kufanele singene yezinyoni, futhi eminye imikhiqizo umzimba kufanele ushiye.

3. endocytosis - kuyinto inqubo lapho molecule esikuthola. ukusonteka okuncane (intussusception) kudalwa ulwelwesi plasma, lapho izidakamizwa okufanele ithuthwe, kugwinyiwe. Lokhu kudinga amandla, futhi ngaleyo ndlela, kuwuhlobo ezokuthutha asebenzayo.

4. Exocytosis: kwenzeka ezitokisini ezihlukene ukususa undigested izinto izinsalela alethwe endocytosis ukuba secrete izinto, njengama-hormone, ama-enzyme, kanye ezokuthutha impahla yonke indlela edlula e umgoqo cell.

ukwakheka kwama-molecule

Cell ulwelwesi - igobolondo begazi ehlanganisa ngokuyisisekelo ka phospholipid futhi ihlukanisa okuqukethwe wonke amaseli kusuka imvelo. Inqubo ukwakhiwa kwenzeka angesabi ngaphansi kwezimo ezivamile. Ukuze uqonde le nqubo futhi kahle ukuchaza isakhiwo kanye umsebenzi cell ulwelwesi, kanye izakhiwo ezidingekayo ukuze bahlole isimo isakhiwo phospholipid, okuyinto sici nokwehlukana kwesakhiwo. Lapho phospholipids imvelo aqueous we cytoplasm ukufinyelela lokuhlushwa ezibucayi, basuke zenziwe micelles, okuyizinto sizinze kakhulu endaweni aqueous.

ulwelwesi izakhiwo

• Ukuzinza. Lokhu kusho ukuthi ngemva kokwakhiwa ngokuwa ulwelwesi akunakwenzeka.
• Amandla. I imvilophi lipid ngamandla ngokwanele ukuvimbela ukudlula izinto polar, esakhiwe ngokuhlanganisa umngcele lwadlulela njengoba solutes (ion, glucose, amino acid), kanye molecule olukhudlwana (amaprotheni).
• Imvelo ashukumisayo. Cishe lena yiyona ebaluleke kakhulu, uma sicabanga isakhiwo esitokisini. I ulwelwesi cell zingavezwa ukuba zamagciwane ezahlukene, futhi kungenziwa eligoqiwe ukugoba futhi ayiphule. Ngaphansi kwezimo ezikhethekile, ezifana Fusion vesicles luthela noma kungaba siphukile, kodwa okwesikhashana kuphela. Ekamelweni lokushisa, yezingxenye lipid ku njalo, ezinyakazayo kunezinxushunxushu, ukwakha umngcele uketshezi esitebeleni.

Fluid imodeli KaMose

Ekhuluma isakhiwo kanye umsebenzi cell ulwelwesi, kubalulekile ukuqaphela ukuthi isethulo lanamuhla we ulwelwesi njengoba uketshezi imodeli KaMose, kwathiwa uhlolwa ososayensi ngo-1972 ngu-Singer futhi Nicholson. ithiyori yabo ibonisa izici ezintathu oyinhloko isakhiwo ulwelwesi. Integral ulwelwesi amaprotheni neqhaza iphethini KaMose ukuze ulwelwesi, futhi ziyakwazi ukuhamba lateral indiza ngenxa yesimo lenhlangano lipid oluyingozi. amaprotheni Transmembrane nazo engase ephathekayo. Isici esibalulekile salo isakhiwo ulwelwesi kuyinto asymmetry yayo. Kuyini isakhiwo iseli? I cell ulwelwesi, i-nucleus, amaprotheni nokunye. Iseli iyunithi ebalulekile yokuphila, futhi zonke izinto eziphilayo aqukethe eyodwa noma amaningi amaseli, ngamunye ephethe isithiyo yemvelo ehlukanisa ke kusukela imvelo. Umnyele elingaphandle iseli ubizwa nangokuthi ulwelwesi plasma. Siqukethe izinhlobo ezine ezihlukene molecule: phospholipids, cholesterol, amaprotheni kanye carbohydrate. Fluid imodeli KaMose Uchaza isimo ulwelwesi cell kanje: nezimo futhi nokunwebeka, ukuvumelana sifana amafutha yemifino, ukuze wonke amangqamuzana ngamanye nje ukuntanta konemimoya ketshezi, futhi bekwazi ukuthutha bayokhonza singatsheki ngaphakathi lo igobolondo. KaMose limelela into yakhiwa izingxenye eziningi ezahlukene. Ngo ulwelwesi plasma linikezwa phospholipids, cholesterol amangqamuzana, amaprotheni kanye carbohydrate.

phospholipids

Phospholipids bakha isakhiwo eziyisisekelo ulwelwesi cell. Lezi zinhlayiya babe ekupheleni ezimbili ezihlukene: inhloko kanye nomsila. Ukuphela Ikhanda licishe iqembu phosphate futhi hydrophilic. Lokhu kusho ukuthi-ke ikhangwa molecule yamanzi. Umsila siqukethe hydrogen ne-carbon athomu, ngokuthi okunamafutha acid ngamaketanga. Lezi amaketanga kukhona hydrophobic, bengakuthandi azihlanganise amangqamuzana amanzi. Le nqubo iyafana kwenzekani uma uthele amafutha emanzini, okusho awusebenzi chaza kuwo. Izici isakhiwo cell ulwelwesi ezihlobene okuthiwa lipid bilayer, esakhiwa phospholipids. Hydrophilic phosphate amakhanda njalo kahle lapho kukhona amanzi ngesimo uketshezi intracellular kanye extracellular. Imisila hydrophobic phospholipids e ulwelwesi ihlelwe ngendlela yokuthi obenza babe kude amanzi.

Cholesterol, amaprotheni kanye carbohydrate

Ukuzwa izwi "cholesterol", abantu ngokuvamile abacabanga ukuthi kubi. Kodwa eqinisweni, cholesterol iyisici esibalulekile cell ulwelwesi. i-molecule wayo siqukethe amasongo amane e-hydrogen ne-carbon ama-athomu. Ziyakwazi hydrophobic futhi atholakala phakathi imisila hydrophobic ku lipid bi ungqimba. ukubaluleka yabo iwukuhlale ukungaguquguquki, bona baqinise ulwelwesi, ekuvimbeleni ukunquma. cholesterol molecule futhi ubambe imisila phospholipid ukuza mbeni futhi osemanzi. Lokhu kuqinisekisa fluidity nakalula. Ulwelwesi amaprotheni abe umsebenzi enzyme ukusheshisa zamakhemikhali, ukwenza njenge-receptor ngoba molecule ethize noma izinto zithutha ngokusebenzisa ulwelwesi cell.

Ama-carbohydrate, noma ushukela, zitholakala kuphela ohlangothini extracellular we ulwelwesi cell. Bebonke bakha le glycocalyx. Linikeza cushioning nokuvikelwa ulwelwesi plasma. Ngokusekelwe izakhiwo kanye nezinhlobo carbohydrate glycocalyx umzimba amaseli ingaze futhi ukunquma ukuthi kudingeka khona noma cha.

amaprotheni ulwelwesi

Isakhiwo ulwelwesi cell ka eyeseli isilwane kakhulu ukukholelwa ngaphandle isakhi enjalo ephawulekayo amaprotheni. Naphezu kwalokhu, kukhona kakhulu eliphansi kuya ubukhulu nezinye ezibalulekile ingxenye - lipids. Kunezinhlobo ezintathu eziyisisekelo ulwelwesi amaprotheni.

• Integral. Khangela, basibekele ngokuphelele bi ungqimba, lo cytoplasm kanye medium extracellular. Bona afeze ezokuthutha kanye okuwuphawu umsebenzi.
• Neuropathy. Amaphrotheni enamathiselwe ulwelwesi ngokusebenzisa electrostatic, noma i-hydrogen izibopho e evele yabo cytoplasmic noma extracellular. Bazibandakanye ngokuyisisekelo njengoba yasibamba kusho amaprotheni ebalulekile.
• Transmembrane. Basebenta enzymatic nemisebenzi okuwuphawu, futhi modulate isakhiwo eziyisisekelo lipid bi ungqimba ulwelwesi.

Imisebenzi ka-ulwelwesi yemvelo

Umthelela hydrophobic okuyinto elawula ukuziphatha hydrocarbon emanzini, ukulawula izakhiwo ezakhiwe ulwelwesi lipids kanye ulwelwesi amaprotheni. Abaningi ulwelwesi izakhiwo anikezwe abathwali lipid bi izingqimba, ukwakha isakhiwo isizinda sabo bonke ulwelwesi begazi. Integral ulwelwesi kwamaprotheni kancane kufihlwe lipid bi ungqimba. amaprotheni Transmembrane unayo inhlangano ezikhethekile amino acid ngokulandelana yabo eyinhloko.

Neuropathy ulwelwesi amaprotheni zifana kakhulu encibilikayo, kodwa kubuye kuhlotshaniswe ulwelwesi. Akhethekile cell ulwelwesi kukhona ezikhethekile cell umsebenzi. Njengoba Isakhiwo nemisebenzi cell ulwelwesi sinomthelela umzimba? Sendlela ukwakha ulwelwesi begazi incike ekuqinisekiseni ukusebenza wonke umzimba. Kusukela organelles intracellular, ekuxhumaneni extracellular cell-cell, izakhiwo ulwelwesi ezidingekayo ukuze inhlangano kanye nokwenziwa kwemisebenzi begazi. Eziningi zalezi zinhlelo kwesakhiwo obusebenzayo zivamile bacterium, amaseli eukaryotic futhi amagciwane wasibekela. Zonke ulwelwesi begazi esakhiwe phezu lipid bi ungqimba, elibangela ukuba khona eziningi ezijayelekileko. amaprotheni ulwelwesi babe nezinkolelo ezihlukahlukene imisebenzi ethize.

• Izilawuli. Ulwelwesi plasma lamaseli ichaze imingcele cell nokuxhumana imvelo.
• Ezokuthutha. Intracellular ulwelwesi cell ihlukaniswe eziningana amabhlogo ukusebenza nge ehlukene Ukwakheka yangaphakathi, ngamunye okusekelwa ukusebenza kwezithuthi kudingekile ngokuhlanganyela permeability control.
• Esiginali transduction. Fusion ulwelwesi ihlinzeka ngendlela yokuba intracellular isixwayiso vesicular nokuvimbela zonke izinhlobo amagciwane ngokukhululekile faka cell.

Inani netiphetfo

Isakhiwo uma kubanda ulwelwesi olungaphandle iseli kuthinta wonke umzimba. Kufeza indima ebalulekile ekuvikeleni ubuqotho, okuvumela Ukungena izinto akhethiwe kuphela. Kuba yisikhathi futhi lapho base ezinhle zokuthola cytoskeleton futhi udonga cell, esiza ekunakekeleni cell ukuma. Lipids bakha mayelana 50% nenqwaba ulwelwesi lamaseli kakhulu, nakuba lokhu kuyehluka kuye ngohlobo ulwelwesi. Isakhiwo yangaphandle cell ulwelwesi ezincelisayo ezinzima, kukhona esasingahlala ezine phospholipid eziyisisekelo. Kuvele impahla ebalulekile lipid bi izingqimba wukuthi beziphatha njengoba ketshezi ezimbili ntathu lapho amangqamuzana ngamanye amahhala ukujikisa bese ukuhambisa ndlela lateral. Lokhu fluidity - lokhu kuyinto impahla ebalulekile ulwelwesi, okuyinto kunqunywa kuye lokushisa kanye lipid kwengoma. Ngenxa hydrocarbon indandatho isakhiwo cholesterol kudlala indima ekunqumeni fluidity ulwelwesi. permeability okukhetha ulwelwesi yemvelo molecule encane evumela iseli ukuqapha kanye nokugcina isakhiwo layo langaphakathi.

Uma ucabangela isakhiwo amaseli (cell ulwelwesi, i-nucleus, nokunye), singaphetha ngokuthi umzimba - ke self umqondo uhlelo ukuthi lenyama Ungazilimazi futhi iyohlala funa izindlela lokuba kubuyiselwe futhi ukuvikela ekusebenzeni kahle wonke amangqamuzana.