Isakhiwo kanye Nomsebenzi we-Cytoskeleton
I-cytoskeleton iyisici esibalulekile samaseli e-eukaryotic, enikeza uhlaka lwesakhiwo futhi yenza imisebenzi ehlukahlukene yemishini. Kulesi sihloko, sizohlola ngokujulile isakhiwo se-cytoskeleton, izakhi ezahlukahlukene eziyakhayo, kanye nemisebenzi ethile eyenziwa yi-element ngayinye ekugcineni ukusinda kweseli.
Isakhiwo se-Cytoskeleton
I-cytoskeleton yakhiwe izinhlobo ezintathu eziyinhloko zemicu yamaprotheni: ama-microtubules, ama-microfilaments (noma ama-actin filaments), kanye nemicu ephakathi. Uhlobo ngalunye lwalezi zinhlobo zemicu lunezici nemisebenzi ehlukile.
1. Ama-Microtubules
Ama-Microtubules angamasilinda amade akhiwe yi-protein tubulin. Angama-25 nm ububanzi futhi angakhula futhi anciphe ngokushesha ngenqubo eyaziwa ngokuthi i-microtubule dynamics. Ama-Microtubules avame ukuhlelwa eduze kwesikhungo sokuhlela ama-microtubule (MTOC), njenge-centrosome emaseli ezilwane.
Ama-microtubules anemisebenzi eminingana ebalulekile:
– Ukuthuthwa Kwangaphakathi Kweseli: ‘Njengendlela’ yokuthuthwa kwama-organelle nama-vesicle ngaphakathi kwamaseli.
– Ukuhlukaniswa kwe-Chromosome: Kwakha idivayisi ye-spindle ngesikhathi se-mitosis kanye ne-meiosis, okuqinisekisa ukusatshalaliswa okufanele kwe-chromosome.
– Inikeza Isakhiwo Nokusekela: Inikeza ukuma kweseli futhi inquma i-polarity yeseli.
2. Ama-Microfilament
Ama-microfilament, aziwa nangokuthi ama-actin filaments, akhiwe yi-protein actin futhi anobubanzi obungaba ngu-7 nm, okwenza abe ama-filament amancane kakhulu ku-cytoskeleton. Anamandla amakhulu futhi angapholimitha ngokushesha futhi anciphise i-polymer.
Imisebenzi eyinhloko yama-microfilaments ihlanganisa:
– Ukuhamba Kwamaseli: Kusekela ukunyakaza kwamaseli ngezindlela ezifana nokunyakaza kwe-ameboid kanye nokwandiswa kwe-pseudopodia.
– Ukufinyela Kwemisipha: Isebenzisana ne-myosin ukuze ikhiqize ukufinyela kwemisipha.
– Ukuzinza Kwesakhiwo Seseli: Kusekela isakhiwo se-microvilli ebusweni bamaseli e-epithelial.
3. Izifilamenti Eziphakathi
Izintambo eziphakathi ziphakathi kwama-microtubules nama-microfilament, anobukhulu obungaba ngu-10 nm. Zihlala isikhathi eside futhi azinamandla kangako kunezinye izinhlobo ezimbili zezintambo. Zakhiwe ngamaprotheni ahlukahlukene, kufaka phakathi i-keratin, i-vimentin, kanye ne-neurofilament, kuye ngohlobo lweseli.
Imisebenzi yemicu ephakathi ihlanganisa:
– Amandla Okusebenza: Kwandisa amandla okudonsa emaseli nasezicutshini.
– Ukulungiswa Kwesakhiwo Esiyinhloko: Kusiza ukugcina isimo nokuqina kwengaphakathi.
– Ukwakheka kwe-Desmosome: Kuhlinzeka ngokuxhumana okuqinile phakathi kwamaseli.
Umsebenzi Ophelele we-Cytoskeleton
Ukuhlanganiswa kwalezi zinhlobo ezintathu zemicu kuvumela i-cytoskeleton ukuthi yenze imisebenzi eyahlukahlukene ebalulekile ekusindeni kweseli kanye nokusebenza kahle kwalo. Nazi ezinye zemisebenzi eyinhloko ye-cytoskeleton iyonke:
1. Ukuhlinzeka Ngefomu Nokusekelwa Kwesakhiwo
I-cytoskeleton isebenza njengohlaka ngaphakathi kwamaseli, ihlinzeka ngesimo kanye nokumelana nokucindezeleka komshini. Isibonelo, amaseli abomvu egazi anesimo esihlukile se-biconcave, esinqunywa kakhulu yinethiwekhi yawo ye-cytoskeleton.
2. Ukulawulwa Kokutholakala Kwangaphakathi Kwamaseli
Ngokusebenzisa izakhi ze-cytoskeletal, amaseli angalawula indawo yama-organelle ahlukahlukene ngaphakathi kwe-cytoplasm. Ama-microtubules asebenza 'njengemigwaqo emikhulu' yamaprotheni e-motor njenge-kinesin ne-dynein, athwala ama-vesicle nama-organelles aye ezingxenyeni ezahlukene zeseli.
3. Ukuhamba Kwamaseli
I-cytoskeleton idlala indima ebalulekile ekuhambeni kwamaseli, kungaba ngokusebenzisa indawo engaphansi komhlaba (isibonelo enkambisweni yokuphulukiswa kwenxeba) noma ngokusebenzisa indawo ewuketshezi (isibonelo, ukubhukuda kwesidoda kusetshenziswa i-flagella esekelwa yi-microtubules).
4. Ukwahlukaniswa Kweseli
Ngesikhathi sokuhlukaniswa kwamaseli, i-cytoskeleton idlala indima ebalulekile ekwakhekeni kwe-mitotic spindle, ehlukanisa ama-chromosome nezinsika eziphambene zeseli. Ama-microfilaments nawo akha indandatho egoqekayo esiza iseli ukuthi lihlukane kabili.
5. Ukudluliselwa Kwesignali
I-cytoskeleton nayo ihilelekile ekudlulisweni kwesignali yeselula. Izingxenye ze-cytoskeleton zingasebenzisana nama-receptors angaphezulu kweseli kanye namanye amaprotheni okubonisa izimpawu, okusiza ukudlulisa izimpawu ezivela ebusweni beseli ziye kuyi-nucleus, okuthonya ukusebenza kwezakhi zofuzo kanye nezimpendulo zamaseli.
Indima Ye-Cytoskeleton Empilweni Nasezifweni
Ukubaluleka kwe-cytoskeleton kudlulela ngale kokusebenza okuvamile kweseli futhi kudlala indima ebalulekile ezifweni zabantu. Isibonelo, izifo eziningana, njengezifo eziwohlokayo zemizwa, zibangelwa ukungasebenzi kahle kwe-microtubule. I-Alzheimer's kanye ne-Parkinson's ziyizibonelo zezifo lapho amaphethini e-microtubule ephazamiseka khona, okuholela ekuphazanyisweni kokuthuthwa kwangaphakathi kweseli, futhi ekugcineni, ukuwohloka kwemizwa.
Umdlavuza ungesinye isibonelo lapho i-cytoskeleton idlala indima ebalulekile. Ukukhula nokusabalala kwamaseli omdlavuza kuvame ukuhlotshaniswa nezinguquko ku-microfilament kanye ne-microtubule dynamics, okwenza kube lula ngamaseli omdlavuza ukufuduka nokuhlasela ezinye izicubu.
Ngaphezu kwalokho, izifo zofuzo ezifana ne-epidermolysis bullosa simplex zibangelwa izinguquko ku-gene efaka i-keratin, ingxenye enkulu ye-filaments ephakathi. Lezi zinguquko ziholela ekubuthakatheni kwesikhumba kanye nokwakheka kwama-blister ngenxa yokuphazamiseka kwamandla okusebenza kwamaseli esikhumba.
Isiphetho
I-cytoskeleton iyisimiso sama-molecule esiyinkimbinkimbi nesiguquguqukayo, esibalulekile cishe kuzo zonke izici zomsebenzi wamaseli. Kusukela ekuhlinzekeni ngesimo nesakhiwo, ukusekela ukunyakaza, ukuhlela ama-organelle, kuya ekuhlanganyeleni ekuhlukanisweni kwamaseli kanye nokudluliselwa kwesignali, i-cytoskeleton iyisici esibalulekile ku-biology yamaseli.
Ucwaningo luyaqhubeka nokuthuthukisa ukuqonda izindlela kanye nemisebenzi yezingxenye ze-cytoskeleton, kanye nendima yazo empilweni nasezifweni. Ukuqonda kangcono umsebenzi we-cytoskeleton kungavula indlela yezindlela zokwelapha ezintsha kanye nokwelashwa kwezifo ezihilela ukungasebenzi kahle kwe-cytoskeleton.
Ngakho-ke, kungaqondakala ukuthi i-cytoskeleton iyisici sesakhiwo nesisebenzayo esingagcini nje ngokugcina ubuqotho bamaseli kodwa futhi esivumela amaseli ukuthi asebenze futhi azivumelanise nezimo ezahlukahlukene zezinto eziphilayo.
