I-DNA Iyachazwa Futhi Ichazwa

-Delile

• Mayelana ne-DNA
• I-DNA kwezempilo, izifo kanye nokuguga
• I-genome yakho ebanzi
• Ukulimala nokuguqulwa kwezakhi zofuzo
• I-DNA nokuguga
• Yini eyenziwe nge-DNA?
• Ngabe i-DNA ibukeka kanjani?
• Yini eyenziwa yi-DNA?
• I-DNA isiza umzimba wakho ukuba ukhule
• Uthola kanjani kusuka kukhodi ye-DNA kuya kuphrotheni?
• Itholakala kuphi i-DNA?
• Amaseli e-eukaryotic
• Amaseli we-Prokaryotic
• Kwenzekani lapho amaseli akho ehlukana?
• Ukudla okudlela endlini

Kungani i-DNA ibaluleke kangaka? Kalula nje, i-DNA iqukethe iziyalezo ezidingekayo ekuphileni.

Ikhodi engaphakathi kwe-DNA yethu inikeza izinkomba zokwenza amaprotheni abalulekile ekukhuleni kwethu, ekukhuleni nasempilweni ephelele.

Mayelana ne-DNA

I-DNA imele i-deoxyribonucleic acid. Yenziwe ngamayunithi wamabhulokhi wokwakha ezinto eziphilayo abizwa ngama-nucleotide.

I-DNA iyimolekyuli ebaluleke kakhulu hhayi kubantu kuphela, kodwa nakwezinye izidalwa eziningi. I-DNA iqukethe izinto zethu zofuzo kanye nezakhi zethu zofuzo - yilokho okusenza sihluke.

Kepha yini empeleni i-DNA yenza? Qhubeka ufunda ukuthola okuningi ngesakhiwo se-DNA, ukuthi yenzani, nokuthi kungani kubaluleke kangaka.

I-DNA kwezempilo, izifo kanye nokuguga

I-genome yakho ebanzi

Isethi ephelele ye-DNA yakho ibizwa nge-genome yakho. Iqukethe izisekelo eziyizigidi eziyizinkulungwane ezintathu, izakhi zofuzo ezingama-20 000, namabhangqa angama-23 ama-chromosomes!

Uzuza uhhafu we-DNA yakho kubaba wakho nengxenye kumama wakho. Le DNA ivela esidunjini naseqandeni, ngokulandelana.

Izakhi zofuzo empeleni zakha okuncane kakhulu kofuzo lwakho - iphesenti elilodwa kuphela. Amanye amaphesenti angama-99 asiza ukulawula izinto ezifana nokuthi kukhiqizwa nini, kanjani, futhi ngamanani amaprotheni.

Ososayensi basaqhubeka nokufunda kabanzi ngale DNA "engakhodi".

Ukulimala nokuguqulwa kwezakhi zofuzo

Ikhodi ye-DNA ithambekele ekulimaleni. Eqinisweni, kulinganiselwa ukuthi izehlakalo zokulinyazwa kwe-DNA ezingamashumi ezinkulungwane zenzeka nsuku zonke engqamuzaneni ngalinye lethu. Ukulimala kungenzeka ngenxa yezinto ezifana namaphutha ekuphindaphindeni kwe-DNA, ama-radicals amahhala, nokuchayeka emisebeni ye-UV.

Kepha ungesabi! Amaseli akho anamaprotheni akhethekile akwazi ukuthola nokulungisa amacala amaningi omonakalo we-DNA. Eqinisweni, kunezindlela okungenani ezinhlanu ezinkulu zokulungisa i-DNA.

Ukuguquka kwezakhi zofuzo kuyizinguquko ekulandelaneni kwe-DNA. Ngezinye izikhathi zingaba zimbi. Lokhu kungenxa yokuthi ushintsho kwikhodi ye-DNA lungaba nomthelela ongezansi ngendlela okwenziwa ngayo amaprotheni.

Uma iphrotheni lingasebenzi kahle, kungavela izifo. Ezinye izibonelo zezifo ezenzeka ngenxa yokuguquka kohlobo olulodwa zifaka i-cystic fibrosis ne-sickle cell anemia.

Ukuguquka kwezakhi zofuzo nakho kungaholela ekwakhekeni komdlavuza. Isibonelo, uma izakhi zofuzo ezifaka amaprotheni abandakanyeka ekukhuleni kwamaselula ziguqulwa, amaseli angakhula futhi ahlukane angalawuleki. Ezinye izinguquko ezibanga umdlavuza zingazuzwa njengelifa kanti ezinye zingatholwa ngokuvezwa ama-carcinogens afana nemisebe ye-UV, amakhemikhali noma intuthu kagwayi.

Kepha akuzona zonke izinguquko ezibi. Sibazuza ngaso sonke isikhathi. Ezinye azinabungozi kanti ezinye zinomthelela ekwahlukaneni kwethu njengohlobo oluthile.

Izinguquko ezenzeka ngaphezu kwephesenti elilodwa labantu zibizwa ngama-polymorphisms. Izibonelo zamanye ama-polymorphisms umbala wezinwele nowamehlo.

I-DNA nokuguga

Kukholakala ukuthi umonakalo we-DNA ongalungisiwe unganqwabelana njengoba sikhula, kusize ukushayela inqubo yokuguga. Yiziphi izici ezingaba nomthelela kulokhu?

Okuthile okungadlala indima enkulu ekulimaleni kwe-DNA okuhambisana nokuguga ukulimala ngenxa yama-radicals amahhala. Kodwa-ke, le ndlela eyodwa yomonakalo ingahle inganeli ukuchaza inqubo yokuguga. Kunezici eziningana ezingabandakanyeka futhi.

Okuthi kungani umonakalo we-DNA uqoqeka njengoba sikhula kusekelwe ekuziphendukeleni kwemvelo. Kucatshangwa ukuthi ukulimala kwe-DNA kulungiswa ngokwethembeka okukhulu lapho sesineminyaka yokuzala futhi sinabantwana. Ngemuva kokuthi sidlulile eminyakeni yethu ephakeme yokuzala, inqubo yokulungisa iyehla ngokwemvelo.

Enye ingxenye ye-DNA engabandakanyeka ekugugeni ngama-telomere. Ama-Telomeres anwebekayo wokulandelana okuphindaphindayo kwe-DNA okutholakala ekugcineni kwama-chromosomes akho. Zisiza ukuvikela i-DNA ekulimaleni, kepha futhi zifinyeza ngokujikeleza ngakunye kwe-DNA.

Ukunciphisa i-Telomere kuhlotshaniswe nenqubo yokuguga. Kutholakale nokuthi ezinye izinto zokuphila ezifana nokukhuluphala ngokweqile, ukuvezwa intuthu kagwayi, kanye nengcindezi engokwengqondo kungaba nomthelela ekunciphiseni i-telomere.

Mhlawumbe ukwenza izinqumo zokuphila okunempilo njengokugcina isisindo esinempilo, ukulawula ukucindezeleka, nokungabhemi kunganciphisa ukunciphisa i-telomere? Lo mbuzo uyaqhubeka nokuthakazelisa kakhulu kubaphenyi.

Yini eyenziwe nge-DNA?

I-molecule ye-DNA yakhiwe ngama-nucleotide. I-nucleotide ngayinye inezinto ezintathu ezihlukene - ushukela, iqembu le-phosphate, nesisekelo se-nitrogen.

Ushukela oku-DNA ubizwa nge-2’-deoxyribose. Lezi zinhlayiya zikashukela ziyashintshana namaqembu e-phosphate, akha "umgogodla" wentambo ye-DNA.

Ushukela ngamunye ku-nucleotide unesisekelo se-nitrogen esixhunywe kuso. Kunezinhlobo ezine ezahlukahlukene zezisekelo ze-nitrogen ezitholakala ku-DNA. Kubandakanya:

• i-adenine (isiGreki)
• i-cytosine (C)
• i-guanine (G)
• i-thymine (iTrojan)

Ngabe i-DNA ibukeka kanjani?

Imicu emibili ye-DNA yakha isakhiwo esingu-3-D esibizwa nge-double helix. Uma kuboniswa, kubukeka okufana nesitebhisi esijikiswe saba yisigaxa lapho amabhangqa ayisisekelo kungamarung futhi amathambo kashukela phosphate eyimilenze.

Ngokwengeziwe, kubalulekile ukuthi wazi ukuthi i-DNA esenkabeni yamaseli eukaryotic iqondile, okusho ukuthi ukuphela komucu ngamunye kumahhala. Esitokisini se-prokaryotic, i-DNA yakha isakhiwo esiyindilinga.

Yini eyenziwa yi-DNA?

I-DNA isiza umzimba wakho ukuba ukhule

I-DNA iqukethe imiyalo edingekayo kumzimba - wena, inyoni, noma isitshalo - ukukhula, ukuthuthuka nokuzala. Le miyalo igcinwa ngaphakathi kokulandelana kwamapheya wesisekelo se-nucleotide.

Amaseli akho afunda le khodi izisekelo ezintathu ngasikhathi ukuze akhiqize amaprotheni abalulekile ekukhuleni nasekusindeni. Ukulandelana kwe-DNA okugcina imininingwane yokwenza iphrotheni kubizwa ngokuthi yisakhi.

Iqembu ngalinye lezisekelo ezintathu lihambelana nama-amino acid athile, okuyizakhi zokwakha amaprotheni. Isibonelo, ama-base pair TGG acacisa i-amino acid tryptophan ngenkathi amabanga ayisisekelo we-GGC ecacisa i-amino acid glycine.

Ezinye izinhlanganisela, njenge-T-A-A, T-A-G, ne-T-G-A, nazo zikhomba ukuphela kokulandelana kwamaprotheni. Lokhu kutshela iseli ukuthi lingangezi amanye ama-amino acid kuphrotheni.

Amaprotheni akhiwa izinhlanganisela ezahlukahlukene zama-amino acid. Uma ihlanganiswe ngokulandelana okulungile, iphrotheni ngayinye inesakhiwo esihlukile nokusebenza emzimbeni wakho.

Uthola kanjani kusuka kukhodi ye-DNA kuya kuphrotheni?

Kuze kube manje, sifunde ukuthi i-DNA iqukethe ikhodi enikeza iseli ulwazi lokuthi lingawakha kanjani amaprotheni. Kodwa kwenzekani phakathi? Kalula nje, lokhu kwenzeka ngenqubo yezinyathelo ezimbili:

Okokuqala, imicu emibili ye-DNA yahlukana phakathi. Ngemuva kwalokho, amaprotheni akhethekile ngaphakathi kwe-nucleus afunda ama-base pair ku-strand ye-DNA ukudala i-molecule yesithunywa esiphakathi.

Le nqubo ibizwa ngokuthi ukuloba futhi i-molecule eyenziwe ibizwa nge-messenger RNA (mRNA). I-mRNA ingenye uhlobo lwe-nucleic acid futhi yenza ngqo lokho okushiwo yigama layo. Ihamba ngaphandle kwe-nucleus, isebenza njengomyalezo kumishini yeselula eyakha amaprotheni.

Esigabeni sesibili, izingxenye ezikhethekile zeseli zifunda umyalezo we-mRNA ama-base ayisisekelo amabili ngasikhathi sinye futhi zisebenza ukuhlanganisa iphrotheni, i-amino acid nge-amino acid. Le nqubo ibizwa ngokuthi ukuhumusha.

Itholakala kuphi i-DNA?

Impendulo yalo mbuzo ingancika ohlotsheni lwesidalwa okhuluma ngaso. Kunezinhlobo ezimbili zamaseli - i-eukaryotic neprokaryotic.

Kubantu, kune-DNA kuseli ngalinye lethu.

Amaseli e-eukaryotic

Abantu nezinye izinto eziningi banamaseli eukaryotic. Lokhu kusho ukuthi amangqamuzana abo ane-nucleus eboshwe ulwelwesi nezinye izakhiwo eziningana eziboshwe ulwelwesi okuthiwa ama-organelles.

Esitokisini se-eukaryotic, i-DNA ingaphakathi kwe-nucleus. Inani elincane le-DNA libuye litholakale kuma-organelles abizwa nge- mitochondria, okuyizindawo ezinamandla zeseli.

Ngoba kunenani elilinganiselwe lesikhala ngaphakathi kwe-nucleus, i-DNA kufanele ihlanganiswe ngokuqinile. Kunezigaba ezahlukahlukene zokupakisha, kepha imikhiqizo yokugcina iyizakhiwo esizibiza ngama-chromosomes.

Amaseli we-Prokaryotic

Izinto eziphilayo ezinjengebhaktheriya zingamaseli e-prokaryotic. Lawa maseli awanayo i-nucleus noma i-organelles. Emangqamuzaneni e-prokaryotic, i-DNA itholakala iboshwe ngokuqinile phakathi kweseli.

Kwenzekani lapho amaseli akho ehlukana?

Amaseli womzimba wakho ahlukana njengengxenye ejwayelekile yokukhula nentuthuko. Uma lokhu kwenzeka, ingqamuzana ngalinye elisha kufanele libe nekhophi ephelele ye-DNA.

Ukuze uzuze lokhu, i-DNA yakho kufanele yenze inqubo ebizwa ngokuthi ukuphindaphinda. Lapho lokhu kwenzeka, imicu emibili ye-DNA yehlukana phakathi. Ngemuva kwalokho, amaprotheni akhethekile amaselula asebenzisa umucu ngamunye njengesifanekiso sokwenza umucu omusha we-DNA.

Lapho ukuphindaphindwa kuqediwe, kunamamolekyu amabili e-DNA anezinhlangothi ezimbili. Isethi eyodwa izongena kuseli ngalinye elisha lapho ukwahlukana sekuqedile.

Ukudla okudlela endlini

I-DNA ibaluleke kakhulu ekukhuleni kwethu, ekukhiqizweni nasempilweni yethu. Iqukethe imiyalo edingekayo kumaseli akho ukukhiqiza amaprotheni athinta izinqubo nemisebenzi ehlukahlukene emzimbeni wakho.

Ngenxa yokuthi i-DNA ibaluleke kakhulu, ukulimala noma ukuguqulwa kwesinye isikhathi kwesinye isikhathi kungaba nomthelela ekuthuthukiseni izifo. Kodwa-ke, kubalulekile futhi ukukhumbula ukuthi ukuguquka kwezakhi zofuzo kungasiza futhi kube nomthelela ekwahlukaneni kwethu futhi.