DNA monomer. Seo monomers theha DNA molek'hule?

acid Nucleic, ka DNA ho khetheha, e tsebahala ka tsebo. Ena e hlalosoa ka taba ea hore ba na le lisele tse dintho tse amang polokelo le phetiso ya tlhahisoleseding lona liphatsa tsa lefutso. DNA ntse bulehileng ka 1868, F. Miescher ke molek'hule le thepa matla asiti. Bo-rasaense ba ka hlaloswang hae ho tswa ho nuclei ba lisele tse tšoeu mali - boitshireletso lisele tse tsamaiso. Lilemong tse latelang tse 50, ho ithuta acid nucleic ne a etsa ka linako tse ling, e le bo-rasaense ba ho fetisisa o ne a lumela biochemists ka sehloohong manyolo dintho le boikarabelo ba ho akarelletsa le bakeng sa seo re se futsitseng le mekhoa, liprotheine.

Ho tloha decoding tsa sebōpeho sa DNA, o atlehe ke Watson le Crick ka 1953, qala ka ho ithuta ka botebo, ho ile ha fumanoa hore, acid e deoxyribonucleic - ke polymer le DNA monomers ke nucleotides. mefuta ea bona 'me mehaho e tla ithuta ka ho re ka ho etsa mosebetsi ona.

Nucleotides ka mehaho unit trust oa boitsebiso bo liphatseng tsa lefutso

E mong oa thepa ea bohlokoa ea taba e phelang - e sa ho boloka le phetiso ya tlhahisoleseding e mabapi le mohaho le mesebetsi ea lisele 'me kaofela phelang. karolo ea ena e etsoa deoxyribonucleic acid e le DNA monomers - nucleotides emela mofuta oa "diboloko tse ahang" ho tloha eo moralo ikhetha, 'me a haha ntho lefutso. Nahana ka seo lipontšo tataisoang liphoofolo tse hlaha, ho bōpa supercoil acid e nucleic.

Tsela ea ho theha nucleotides

E le ho araba potso ena, re hloka tsebo tsa k'hemistri oa metsoako manyolo. Ka ho khetheha, re hopola hore ka tlhaho ho na le ke sehlopha ea naetrojene-e nang le heterocyclic glycosides amanang ho monosaccharides - pentoses (ribose kapa deoxyribose). Ba bitsoa nucleosides. Mohlala, adenosine le nucleosides tse ling ba teng le ka cytosol ea sele. Ba ikutloa joang ka limolek'hule tsa esterification le asiti orthophosphoric. Lihlahisoa tsa tshebetso ena le tla nucleotides. E mong le e monomer DNA, 'me ho na le mefuta e' nè, o na le lebitso, ho etsa mohlala, guanine, thymine le cytosine nucleotide.

Purine DNA monomers

Ka Biochemistry amohetse tlhophiso hore a arola DNA monomers le sebopeho bona ka lihlopha tse peli: ka mohlala, purine e adenine le guanine nucleotides. Ba na le ka ho hlophisoa bona purine derivatives - ntho manyolo ho ba le moralo o balletsweng C ₅ H ₄ N _4. Monomer DNA - guanine nucleotide, e boetse e na le purine nitrogenous botlaaseng amanang ho deoxyribose N-glycosidic tlamo e ho ba betokonfiguratsii.

pyrimidine nucleotides

makalana Nitrogenous, e bitsoang cytidine le thymidine ke pyrimidine derivatives ea taba manyolo. moralo oa oona ke C ₄ H ₄ N _2. Molek'hule ke a bataletseng tšeletseng membered heterocycle nang pedi naetrojene liathomo. E o tsejoa hore ho fapana le nucleotides thymine ka limolek'hule tsa acid e ribonucleic, tse kang rRNA, tRNA, mRNA, e ne e ena uracil monomer. Ka tshebetso ya ho mongwalollo, nakong debiting tlhahisoleseding ho tswa ho DNA molek'hule phatsa ea lefutso mRNA thymine nucleotide e nkeloa sebaka ke adenine, adenine nucleotide le - ho uracil ka mRNA nascent ketane. Hore se nang leeme e le ho kena latelang: A - Y, T - A.

melao Chargaff e

Ka karolo fetileng re se mokhoa o sa fellang ama holim 'melao-motheo ea latelwa le monomers ka liketane DNA le mRNA phatsa ea lefutso e rarahaneng. Tummeng biochemist E. Chargaff thehile thepa haholo ikhethang ea limolek'hule tsa acid e deoxyribonucleic, e leng, hore palo e ea nucleotides adenine ho oona ea kamehla lekanang thymine, le guanine - cytosine. Ka sehloohong nankolo melao-motheo ea Chargaff a sebeletsa e le ho ithuta Watson le Crick, akanya hore monomers theha DNA molek'hule, 'me seo ba na le mokhatlo o hlophisitsoeng oa tlhaloganya sebaka. paterone ke e mong outputted ke Chargaff 'me a bitsa complementarity molao-motheo, e bontsha amana lik'hemik'hale tsa purine le pyrimidine makalana le bokhoni ba bona ba ho sebelisana pakeng tsa bona ho theha litlamo hydrogen. Sena se bolela hore le tokisetso ea monomers ka palesa bobeli DNA tieo deterministic Kahoo, bo fapaneng A Strand pele ea DNA e ka feela ba T le basebetsi ba bang litlamo le tse peli hydrogen pakeng tsa bona. Feela cytosine ka hantle bo fapaneng guanine nucleotide. Tabeng ena, pakeng tsa makalana nitrogenous theha litlamo hydrogen tse tharo.

Karolo e phethoang ke nucleotides ka khoutu liphatsa tsa lefutso

Ho kenya tshebetsong, ba itšoara joang etsahala ka ribosomes tsa protheine biosynthesis, ho na le boitsebiso bo mabapi le phetolelo ea mochine oa amino acid e Sebopeho sa peptide tatelano ea nucleotides ka mRNA tatelano ea-amino acid. Ho ile ha fumaneha hore e meraro e haufi monomer tsoele tlhahisoleseding e mabapi le e mong oa 20 khoneha-amino acid. ketsahalo ena e bitsoa ho khoutu liphatsa tsa lefutso. Ka bua le mathata a baeloji ea limolek'hule le sebelisitsoe ho bona hore ka bobeli e peptide amino acid e hlophisoa le ho hlakisa potso ena: tse theha DNA molek'hule monomers, ka mantsoe a mang, seo ho hlophisoa ha phatsa ea lefutso e lekanang. Ka mohlala, triplet (codon) AAA ka phatsa ea lefutso e encodes le amino acid e phenylalanine ka protheine molek'hule, 'me ka khoutu liphatsa tsa lefutso e tla lumellane triplet UUU ka ketane mRNA.

Sebelisana tsa nucleotides nakong DNA boikatiso

Ka pele tlhaloseditswe ke, ya diyuniti mehaho ea monomers DNA - e nucleotides. tatelano bona itseng ka lipotoloho le ke thempleite bakeng sa tswakana thulaganyou e tlaasana acid e deoxyribonucleic molek'hule. ketsahalo ena e hlaha ka S-sethaleng ea lisele interphase. The nucleotide tatelano ea bukeng limolek'hule DNA ka liketane tileng mè ke potlakisang tsebetso ea lik'hemik'hale DNA polymerase le molao-motheo oa complementarity (A - C, A - C). Boikatiso bua ka liphetoho tsa popeho tswakana. Sena se bolela hore DNA monomers le sebopeho bona ka ketane ena eo motsoali ke motheo oa, hore ke thempleite bakeng sa likopi tsa tlaasana lona.

Ho ka fetola sebōpeho sa nucleotide ho

Ka tsela eo, a re ke re ka bolela hore acid e deoxyribonucleic - ke mekhoa e tloaetsoeng haholo sebopeho tsa khubu seleng. Ho na le ke e utloahalang tlhaloso: boitsebiso bo liphatseng tsa lefutso bolokwa ka chromatin tsa khubu le, e lokela ho tsoela pele le replicated ntle ho khopama. Empa liphatsa tsa lefutso lisele ke kamehla "tlas'a sethunya sa" lintlha tikoloho. Mohlala, joalo lik'hemik'hale mabifi joaloka joala, lithethefatsi, ntšang mahlaseli a kotsi mahlaseli. Kaofela ha bona ke ho thoeng mutagens, tlas'a tšusumetso ea ba eo leha e le efe DNA monomer ka fetola lik'hemik'hale sebopeho bona. khopama sena Biochemistry e bitsoa ntlha phetoho liphatseng tsa lefutso. The maqhubu a ya ketsahalo ea liphatsa tsa lefutso ho lekaneng phahameng seleng. Liphetoho liphatseng tsa lefutso khalemeloa hantle sebetsa seleng ea ho lokisa oona tsamaisong tshebetso, ho akarelletsa le sete ya enzyme.

Ba bang ba bona, joaloka ho thibelo potlakisang tsebetso ea lik'hemik'hale, "khaola" ho nucleotides senyehileng, polymerases lumella tswakana tsa monomers tloaelehile ligase "crosslinked" hlaphoheloa likarolo tse itseng tsa liphatsa tsa lefutso le. Ha mochine ka holimo, ka lebaka le itseng, ka seleng ha se sebetse le haelloang DNA monomer lula molek'hule lona, phetoho liphatseng tsa lefutso e lata ka dithulaganyo tsa popeho tswakana le phenotypically bonahatsa ka mokgwa wa liprotheine le thepa fetoloang, ba sitoa ho phetha mesebetsi hlokahala tlholeho ka metabolism lisele. Sena ke e tebileng mpe Ntlha e, fokotsa seleng ea solofetsa le ho fokotsa bolelele ba nako ba bophelo ba hae.