Sebopeho le Mosebetsi oa DNA Linthong tse Phelang
DNA (Deoxyribonucleic Acid) ke molek'hule ea mantlha e bolokang litaelo tsa liphatsa tsa lefutso hoo e batlang e le linthong tsohle tse phelang. Ho tloha ho libaktheria tse bonolo ho ea ho batho, DNA e sebetsa e le "buka ea tataiso" e tataisang kamoo lisele li holang, li arohanang, li etsang mesebetsi ea metabolism, le ho fetisa litšobotsi ho tloha molokong o mong ho ea ho o mong. Ho utloisisa sebopeho le mosebetsi oa DNA ke motheo oa bohlokoa bakeng sa baeloji ea sejoale-joale, bongaka, temo le baeloji.
Ho Utloisisa DNA le Karolo ea Eona Bophelong
DNA ke thepa ea lefutso e fumanoang ka har'a lisele . Linthong tse phelang tsa eukaryotic tse kang limela, liphoofolo le li-fungus, DNA e bolokiloe haholo-holo ka har'a nucleus ea sele (li-chromosome), 'me e boetse e fumanoa ho li-organelle tse kang mitochondria le li-chloroplast. Linthong tse phelang tsa prokaryotic tse kang libaktheria, DNA e sebakeng sa cytoplasm se bitsoang nucleoid.
Mosebetsi o ka sehloohong oa DNA ke ho boloka tlhahisoleseling ea liphatsa tsa lefutso. Tlhahisoleseling ena e na le "khoutu" ea ho etsa liprotheine, limolek'hule tse etsang boholo ba mesebetsi ea 'mele ea baeloji: ho theha meaho ea sele, ho laola liketso tsa lik'hemik'hale ka li-enzyme, le ho laola kholo le tokiso ea lisele.
Sebopeho sa Motheo sa DNA: Li-Nucleotide e le Li-block tsa Kaho
Sebopeho sa DNA se entsoe ka diyuniti tse nyane tse bitswang di-nucleotide. Nucleotide ka nngwe e na le dikarolo tse tharo tse kgolo:
1. Tsoekere ea Deoxyribose, e leng tsoekere ea khabone e hlano e leng "skeleton" ea li-nucleotide.
2. Lihlopha tsa phosphate, tse hokahanyang nucleotide e le 'ngoe le nucleotide e latelang ho etsa ketane e telele.
3. Metheo ea naetrojene, e leng karolo ea bohlokoa ea ho jara tlhahisoleseling ea liphatsa tsa lefutso.
Metheo ea naetrojene ea DNA e mefuta e mene:
– Adenine (A)
– Thymine (T)
– Cytosine (C)
– Guanine (G)
Tatellano ea metheo ena ea naetrojene ke eona e bolokang tlhahisoleseling ea liphatsa tsa lefutso. Ka mantsoe a mang, metheo ea naetrojene e tšoana le litlhaku tse alfabeteng, 'me tatellano ea tsona e theha "mantsoe" le "lipolelo" tse sebetsang e le litaelo tsa baeloji.
Mohlala oa Helix e 'Meli: Tšibollo ea Bohlokoa ho Baeloji
Sebopeho sa DNA se tsebahalang haholo ke helix e habeli, e ileng ea hlakisoa haholo ka mor'a lipatlisiso tsa James Watson le Francis Crick ka 1953, e tšehetsoang ke data ea diffraction ea X-ray e tsoang ho Rosalind Franklin le Maurice Wilkins. DNA e na le likhoele tse peli tse phuthetsoeng ka har'a selikalikoe, joalo ka lere le sothehileng.
Mohlaleng ona:
– Karolo ea tsoekere-phosphate e etsa lehlakore la "mohele" la lere (lesapo la mokokotlo).
– Metheo ea naetrojene e bopa “marulelo” a kopantsoeng.
Lipara tsa motheo li ikhetha:
– Adenine (A) kamehla e tsamaisana le Thymine (T)
– Cytosine (C) e dula e tsamaisana le Guanine (G)
Kamano pakeng tsa lipara tsa motheo e etsahala ka litlamo tsa haedrojene, tseo, leha li fokola ka bonngoe, li tsitsitseng haholo hobane li ngata ho pholletsa le molek'hule ea DNA.
Matlotlo a Tlatsetsang le Tataiso ea Likhoele tsa DNA
Likhoele tse peli tsa DNA lia tlatsana, ho bolelang hore tatellano ea motheo khoeleng e 'ngoe e khetholla tatellano ea motheo ho e 'ngoe. Haeba khoele e 'ngoe e na le tatellano ea ATCG, joale para ea eona e tlatsanang ke TAGC. Thepa ena e bohlokoa bakeng sa ho ikatisa ha DNA le lefa la liphatsa tsa lefutso.
Ho phaella moo, dithapo tse pedi tsa DNA di tsamaya ka mahlakoreng a fapaneng, tse bitswang antiparallel. Thapo e nngwe e matha ho tloha ho 5' ho isa ho 3', ha e nngwe e le 3' ho isa ho 5'. Tsela ena e tsamaellana le boemo ba diathomo tsa khabone hodima tswekere ya deoxyribose mme e etsa qeto ya hore na dienzyme di sebetsa jwang ha ho kopitswa DNA.
DNA ka har'a li-chromosome: Ho paka Tlhahisoleseding ea Lefutso
Lipheding tsa eukaryotic, DNA ha se sebopeho se lokolohileng empa ho e-na le hoo e kopanngoa ho ba li-chromosome. Ts'ebetso ena ea ho kopanya e kenyelletsa liprotheine tsa histone. DNA e potoloha li-histone ho theha meaho e bitsoang li-nucleosome, tseo ka mor'a moo li menehang hape hore e be likhoele tsa chromatin 'me qetellong e be li-chromosome. Sephutheloana sena se bohlokoa bakeng sa hore DNA e telele e kene ka har'a nucleus e nyane ea sele 'me hape e thusa ho laola phihlello ea liphatsa tsa lefutso bakeng sa tlhahiso kapa "ho bala" ke sele.
Palo ea li-chromosome e fapana ho ea ka mefuta. Batho ba na le li-chromosome tse 46 (lipara tse 23), ha limela tse ling li ka ba le tse ngata ho feta moo.
Mosebetsi o ka Sehloohong oa DNA: Ho Boloka le ho Rua Tlhahisoleseding
1. Litaelo tsa ho Boloka Protheine ea ho Kopanya
DNA e boloka liphatsa tsa lefutso, e leng likarolo tse itseng tse nang le litaelo tsa ho etsa liprotheine tse sebetsang kapa limolek'hule tsa RNA. Ts'ebetsong ea tlhahiso ea liphatsa tsa lefutso, DNA e "fetoleloa" ka mekhahlelo e 'meli e meholo:
– Phetolelo: DNA e kopitsoa ho RNA (haholo-holo mRNA).
– Phetolelo: mRNA e fetoleloa letotong la li-amino acid ho etsa liprotheine.
Liprotheine tse hlahisoang li khetholla thepa le mesebetsi ea lisele. Mohlala, liphatsa tse itseng tsa lefutso li laola ho thehoa ha hemoglobin liseleng tse khubelu tsa mali, ha tse ling li laola li-enzyme tsa tšilo ea lijo.
2. Ho Ikatisa ha DNA bakeng sa Karohano ea Sele
Pele disele di arohana, DNA e lokela ho kopitswa e le hore sele e nngwe le e nngwe ya moradi e be le kopi e tshwanang ya tlhahisoleseding ya lefutso. Tshebetso ena e bitswa ho phetaphetoa ha DNA mme e etsahala ka tsela e sa fetoheng: molek'hule e nngwe le e nngwe e ntjha ya DNA e na le khoele e le nngwe ya kgale le khoele e le nngwe e ntjha.
Ho pheta-pheta ho kenyelletsa li-enzyme tse fapaneng tsa bohlokoa, tse kang:
– Helicase, e lokollang DNA.
– DNA polymerase, e eketsang di-nucleotide tse ntjha ho ya ka dipara tsa motheo.
– Ligase, e kopanyang dikotwana tsa DNA, haholoholo hodima thapo e salang morao.
Ho nepahala ha ho pheta-pheta ho hoholo haholo hobane DNA polymerase e na le bokgoni ba ho hlahloba diphoso ho lokisa diphoso.
3. Ho Laola Mesebetsi ea Sele ka Taolo ea Liphatsa tsa Lefutso
Hase liphatsa tsohle tsa lefutso tse lulang li sebetsa. Lisele li na le mekhoa ea ho bulela kapa ho tima liphatsa tsa lefutso ha ho hlokahala. Sena se bitsoa taolo ea liphatsa tsa lefutso. Mohlala, lisele tsa sebete li kenya tšebetsong liphatsa tsa lefutso tse amanang le ho ntša chefo 'meleng, ha lisele tsa methapo li kenya tšebetsong liphatsa tsa lefutso tse tšehetsang phetiso ea matšoao.
Taolo ea liphatsa tsa lefutso e boetse e susumetsoa ke lintlha tsa epigenetic, e leng liphetoho tse sa fetoleng tatellano ea DNA empa li ama tlhahiso ea eona—joalo ka methylation ea DNA le liphetoho tsa histone.
Liphetoho tsa DNA: Mohloli oa Phapang le Sesosa sa Lefu
DNA e ka fetoha ka tatellano ea motheo oa eona, e bitsoang liphetoho. Liphetoho li ka hlaha ka lebaka la liphoso tsa ho ikatisa, ho pepesehela mahlaseli, lik'hemik'hale, kapa livaerase. Litlamorao lia fapana:
– Liphetoho tsa lefutso li ka ba tse sa nke lehlakore (ha li na phello).
– Liphetoho tsa lefutso li ka ba molemo (fana ka liphetoho tse itseng).
– Liphetoho tsa lefutso li ka ba kotsi 'me tsa baka mafu a liphatsa tsa lefutso.
Mohlala oa phetoho e amang batho ke sickle cell anemia, e leng bothata bo bakoang ke liphetoho tsa jini ea hemoglobin. Leha ho le joalo, moelelong oa ho iphetola ha lintho, liphetoho tsa lefutso le tsona ke mohloli o moholo oa phetoho ea liphatsa tsa lefutso e lumellang khetho ea tlhaho ho sebetsa.
DNA le Nts'etsopele ea Saense
Lithuto tsa DNA li hlahisitse lintlafatso tse ngata, tse kang:
– Teko ea liphatsa tsa lefutso ho fumana mafu kapa likotsi tse futsitsoeng.
– Bafuputsi ba DNA bakeng sa boitsebiso ba motho ka mong.
– Boenjiniere ba liphatsa tsa lefutso temong (lijalo tse hanelang likokoanyana) le meriana (tlhahiso ea insulin).
– Kalafo ea liphatsa tsa lefutso le theknoloji ea CRISPR-Cas9, e lumellang ho hlophisoa ha DNA ka nepo haholoanyane.
Nts'etsopele ena e bontša kamoo DNA e seng feela khopolo ea baeloji, empa hape e le motheo oa theknoloji ea nakong e tlang.
Qetello
DNA ke molek'hule ea bohlokoa bophelong hobane e boloka, e fetisa, 'me e hlahisa tlhahisoleseling ea liphatsa tsa lefutso. Sebopeho sa eona sa li-helical tse peli, ho kopanya motheo o tlatsanang, le ho paka ka har'a li-chromosome ho nolofalletsa DNA ho sebetsa ka botsitso le ka katleho. Mesebetsi ea DNA e kenyelletsa tlhahiso ea protheine, ho ikatisa nakong ea karohano ea sele, le taolo ea ts'ebetso ea sele ka tlhahiso ea liphatsa tsa lefutso. Ka lehlakoreng le leng, liphetoho ho DNA e ka ba mohloli oa mefuta-futa ea liphatsa tsa lefutso le sesosa sa maloetse. Ka tsoelo-pele ea saense, kutloisiso ea DNA e ntse e tsoela pele ho bula menyetla e meholo bakeng sa theknoloji ea baeloji, bongaka le ho rarolla mathata a batho.
Haeba o batla, nka eketsa le setshwantsho se bonolo (ka mokhoa wa tlhaloso) kapa ka etsa mofuta o "ratwang" haholo wa sengoloa sena bakeng sa baithuti ba sekolo se mahareng/se phahameng.
