I-DNA kanye nofuzo: Isisekelo Sokuphila
Ezweni lezinto eziphilayo, mhlawumbe azikho izingxenye eziyisisekelo nezibalulekile kune-DNA nezakhi zofuzo. Zombili ziyizihluthulelo zokuvula ukuqonda kwethu ukuthi izinto eziphilayo zikhula kanjani, zisebenza kanjani, futhi ziguquke kanjani. Kodwa-ke, ukuze siziqonde, kumelwe siqale sihlolisise ingxenye ngayinye kanye nokusebenzisana kwazo.
Iyini i-DNA?
I-DNA, noma i-deoxyribonucleic acid, iyi-molecule egcina imiyalelo yezakhi zofuzo edingekayo ekuthuthukisweni, ekukhuleni, ekusebenzeni nasekuzaleni kwazo zonke izinto eziphilayo kanye namagciwane amaningi. Isakhiwo sayo siyi-double helix efana neladi elisontekile, lapho 'imigqa' yakhiwe khona ngamabhangqa ezisekelo ze-nitrogenous: i-adenine (A) ene-thymine (T) kanye ne-cytosine (C) ene-guanine (G).
Ama-molecule e-DNA ahlelwe ngama-chromosome, atholakala kuyi-nucleus yeseli. Emangqamuzaneni omuntu, isibonelo, kunezimbhangqwana ezingama-23 zama-chromosome, ngalinye liqukethe izinkulungwane zezakhi zofuzo. I-DNA iqukethe lonke ulwazi lwezakhi zofuzo, oludluliselwa ezizukulwaneni ngezizukulwane.
Indima Yezakhi Zofuzo Ku-DNA
I-gene iyisigaba esithile se-DNA esibhala ikhodi yeprotheni ethile. I-gene ngayinye inochungechunge oluthile lwesisekelo olunesibopho sokuqondisa ukukhiqizwa kweprotheni ehlukile, ekugcineni enquma izakhiwo nemisebenzi yesidalwa.
Umuntu ngamunye unezakhi zofuzo ezingaba ngu-20.000 kuya ku-25.000. Lezi zakhi zofuzo zisebenza okungaphezu nje kokuba "incwadi yemiyalelo" yomzimba. Izakhi zofuzo zilawula konke kusukela ezinweleni nombala wamehlo kuya ekuthambekeleni kwezifo kanye nokuthambekela ezicini zemvelo.
Inqubo Yokuveza Izakhi Zofuzo
Ukuvezwa kwezakhi zofuzo inqubo lapho ulwazi oluvela kuzakhi zofuzo lusetshenziswa khona ukuhlanganisa imikhiqizo esebenzayo efana namaprotheni. Le nqubo ihilela izinyathelo ezimbili eziyinhloko: ukubhala phansi kanye nokuhumusha.
1. Ukubhalwa phansi: Ngesikhathi sokubhalwa phansi, ingxenye ye-DNA emele i-gene ibhalwa ibe yi-messenger RNA (mRNA). I-enzyme i-RNA polymerase yenza kube lula ukubopha ama-base pairs afanele, iguqule ukubhalwa phansi kwe-DNA kube ukubhalwa phansi kwe-RNA.
2. Ukuhumusha: i-mRNA ibe isihunyushwa ibe yiprotheni ku-ribosome. Ngesikhathi sokuhumusha, ukulandelana kwesisekelo ku-mRNA kuhunyushwa kube ukulandelana kwe-amino acid okwakha iphrotheni. Lokhu kufezwa ngosizo lwama-molecule e-RNA (tRNA) okudlulisa, anezela ama-amino acid athile ngokuya ngokulandelana kwe-codon ku-mRNA.
Ukulawulwa Kwezakhi Zofuzo
Akuzona zonke izakhi zofuzo ezivezwa ngesikhathi esifanayo noma ngamandla afanayo. Ukulawulwa kwezakhi zofuzo inqubo evumela amaseli ukuthi aphendule ezimpawini zangaphandle noma zangaphakathi ngokulungisa ukubonakaliswa kwezakhi zofuzo ezithile.
Le nqubo yokulawula ingenzeka ngezigaba ezahlukene, kusukela ekulawulweni kokubhalwa kwemibhalo kanye nokuqina kwe-mRNA kuya ekulawulweni kwangemva kokuhumusha. Uhlelo lokulawula izakhi zofuzo olusebenza kahle luvumela amaseli ukuthi akhule futhi asebenze kahle endaweni eshintshayo.
Ukuguqulwa kwe-DNA kanye nomthelela wako
Ukuguqulwa kwezakhi zofuzo kuyizinguquko ezenzeka ochungechungeni lwesisekelo se-DNA. Lezi zinguquko zingaba nemiphumela ehlukahlukene, kusukela kokungathathi hlangothi kuya kokulimaza kuya kokuzuzisayo. Ezinye izinguquko eziyingozi zingabangela izifo zofuzo, njenge-cystic fibrosis noma i-sickle cell anemia. Ngakolunye uhlangothi, ukuguqulwa kwezakhi zofuzo nakho kungumthombo obalulekile wokuguquguquka okungaqhuba ukuvela kwemvelo.
Ukuguquka kwezakhi zofuzo kungabangelwa izici ezahlukahlukene, okuhlanganisa imisebe, amakhemikhali, izifo ezibangelwa amagciwane, noma ngisho namaphutha okuphindaphinda kwe-DNA ngokuzenzakalelayo. Izinto eziphilayo zinezindlela zokulungisa i-DNA ezivame ukuphumelela ekulungiseni lezi zinguquko, nakuba zingasebenzi ngaso sonke isikhathi.
Ubuchwepheshe be-DNA kanye ne-Gene
Intuthuko kwezobuchwepheshe bezakhi zofuzo yenze kwaba nokwenzeka ukuguqula nokuphatha i-DNA nezakhi zofuzo ngezindlela ezazingenakwenzeka ngaphambili. Ubunjiniyela bezakhi zofuzo, isibonelo, buvumela ososayensi ukuthi bafake, basuse, noma bashintshe ukulandelana kwe-DNA ngaphakathi kwezakhi zofuzo ukuze bafinyelele imiphumela efiselekayo. Izinto eziphilayo ezakhiwe ngezakhi zofuzo sezivele zisetshenziswa emikhakheni eminingi, kusukela kwezolimo kuya kwezokwelapha.
Amasu amasha okuhlela izakhi zofuzo, njenge-CRISPR-Cas9, asinikeza indlela enembile nephumelelayo yokuhlela i-genome. Lobu buchwepheshe bunesithembiso esikhulu sokwelapha izifo ezahlukahlukene zofuzo ngisho nokulungisa izakhi zofuzo ezonakele emangqamuzaneni abantu.
Ukuziphatha kanye Nekusasa Lezakhi Zofuzo
Ngekhono elingavamile lokulawula i-DNA nezakhi zofuzo kuza imibuzo ebalulekile yokuziphatha. Amandla okushintsha izakhi zofuzo zabantu avula izingxoxo mayelana nokuthuthukiswa kwezakhi zofuzo, ubunjiniyela bezakhi zofuzo zemibungu, kanye nomthelela wazo emphakathini.
Nakuba lobu buchwepheshe bunikeza izinzuzo eziningi ezingaba khona, njengokunciphisa ukusabalala kwezifo zofuzo nokuthuthukisa ikhwalithi yokuphila, kumelwe futhi sicabangele ngokucophelela imiphumela yesikhathi eside kanye nezingozi ezihlobene nobunjiniyela bofuzo.
Ngakho-ke, indima ye-DNA nezakhi zofuzo empilweni ayinakubukelwa phansi. Njengezingxenye eziyisisekelo zofuzo nokuphila, azigcini nje ngokwakha umongo wesakhiwo somzimba sezinto eziphilayo kodwa futhi zithonya ikhwalithi yokuphila kanye nenhlalakahle yomuntu ngamunye. Ngocwaningo oluqhubekayo kanye nokusungula izinto ezintsha, siyaqhubeka nokuphenya ngokujulile ezimfihlakalo zalezi zinto ezimbili ezincane, sinethemba lokuvula imiphetho emisha ekuqondeni kwethu impilo kanye nendawo yonke.
