DNA monomer. Yintoni monomers benza zinemoletyhule DNA?

asidi acid, DNA ethile, waziwa kakuhle ubugcisa. Oku kuchazwe ngenxa yokuba ezi izinto iiseli ezichaphazela ukugcinwa kunye nokusasazwa kolwazi yayo yemfuza. DNA izakuvula ngo-1868, F. Miescher yi zinemoletyhule kunye iipropati enamandla asidi. Izazinzulu ziye zachongwa yakhe eziba iiseli ezimhlophe - iiseli zamajoni omzimba. Kule minyaka ingama-50 izayo, izifundo nucleic zenziwa wambi, njengoko izazinzulu ezininzi bakholwa biochemists izinto eziphambili zendalo onoxanduva kuquka ukuba ilifa iimpawu, iiprotheni.

Ekubeni ekufundeni ye ubume DNA, uqhutywe Watson kunye Crick ngo-1953, uqale isifundo kakhulu, kwaye wafumanisa ukuba, deoxyribonucleic acid - yinto Polymer kunye DNA monomers ke nucleotides. iintlobo zazo nezakhiwo ziza kufundwa sithi kulo msebenzi.

Nucleotides njengeyunithi noshowo ulwazi yemfuza

Enye iimpawu ezibalulekileyo zenkqunto eziphilayo - na ukugcinwa kunye nokusasazwa kolwazi kubume kunye nemisebenzi iiseli kwaye yonke eziphilayo. Le ndima lwenziwa deoxyribonucleic acid kunye DNA monomers - nucleotides bamele uhlobo "iibhloko zokwakha 'ukusuka apho kuyilo elikhethekileyo kweziyobisi wakha yofuzo. Khawuve oko imiqondiso ekhokelwa zasendle, ukudala nucleic supercoil.

Indlela ukwenza nucleotides

Ukuze siphendule lo mbuzo, kufuneka sibe nolwazi ezinye imichiza oganikhi khompawundi. Ngokukodwa, sikhumbula ukuba indalo kukho iqela glycosides nitrogen aqulethe heterocyclic uqhagamshele monosaccharides - pentoses (ribose okanye deoxyribose). Ewe kuthiwa nucleosides. Umzekelo, adenosine kunye nezinye nucleosides ezisegumbini cytosol esiseleni. Idibene molecule le esterification kunye orthophosphoric acid. Le mveliso yale nkqubo kwaye iya nucleotides. monomer DNA nganye, kwaye kukho iindidi ezine, unegama, umzekelo, guanine, thymine kunye cytosine nucleotide.

monomers DNA Purine

Ngamachiza ezinto yamkela kudidi esohlukanisa monomers DNA kunye nesakhiwo ibe ngamaqela amabini: umzekelo, purine na adenine kunye guanine nucleotides. Bona ziqulathe ku avela zabo purine ukubunjwa - into ephilayo kokuba C ifomula ₅ H ₄ N _4. DNA Monomer - nucleotide guanine, nayo siqulethe purine isiseko nitrogen eqhagamshelwe deoxyribose N-glycosidic bond ukuba betokonfiguratsii.

nucleotides pyrimidine

iziseko nitrogen, ekuthiwa cytidine kunye thymidine zizinto nezakhi pyrimidine zenkqunto ephilayo. ifomula wayo C ₄ H ₄ N _2. Molecule a flat heterocycle-membered ezintandathu equlathe athom ezimbini nitrogen. Yinto eyaziwayo ukuba endaweni nucleotides thymine kwi molecule ribonucleic acid, ezifana rRNA, tRNA, mRNA, eziqulathwe monomer uracil. Xa inkqubo ukhutshelo, ngexesha Ukutsalwa inkcazelo kwemolekyuli iDNA gene mRNA thymine nucleotide na indawo adenine, adenine nucleotide kunye - ukuya uracil in mRNA chain lutsha. Loo nto intle ke le entry zilandelayo: A - Y, T - A.

imithetho Chargaff kaThixo

Kwicandelo odlulileyo sele yachukumisa ngokuyinxenye phezu nemigaqo ukuthotyelwa kunye monomers kumakhonkco DNA kunye mRNA gene ezintsonkothileyo. ezinto owaziwayo E. Chargaff yasekwa kakhulu ipropati ekhethekileyo molecule deoxyribonucleic acid, oko kukuthi, ukuba imali nucleotides adenine kuwo kusoloko ulingana thymine, kunye guanine - cytosine. Kuba sisiseko esingundoqo theoretical imigaqo Chargaff wakhonza ukufundisisa Watson kunye Crick, ngawaphi monomers zenza zinemoletyhule DNA, yaye yintoni na umbutho lomhlaba. Enye indlela ofakwe yi Chargaff wabiza complementarity siseko, ibonisa oludla eekhemikhali purine kunye pyrimidine neenqwelwana kunye nokwazi kwabo ukufumana intsebenziswano phakathi kwabo ukwenza imixokelelwane hydrogen. Oku kuthetha ukuba lilungiselelo monomers kuzo zombini imisonto DNA ngqo deterministic Ngoko ke, malunga A mngxilo yokuqala ka-DNA ingaba T kunye nezinye izibophelelo kokuba ezimbini hydrogen phakathi kwabo kuphela. cytosine kuphela zibekwa malunga guanine nucleotide. Kulo mzekelo, phakathi iziseko nitrogen ubuhlobo obuluqilima ezintathu hydrogen.

Indima nucleotides kwi ikhowudi yezofuzo

Ukuphumeza, basabela othatha indawo ribosomes le biosynthesis protein, kukho ulwazi malunga nendlela yokuguqulela le acid acid ukwakhiwa ukulandelelana peptide of nucleotides ngokulandelelana mRNA ye asidi acid. Kwathi kanti loo ndawo monomer ezintathu okufuphi athwale ulwazi malunga enye asidi kunokwenzeka acid 20. Le nto ibizwa ngokuba ikhowudi yezofuzo. Ekujongeni imingeni ezinto eziphilayo isetyenziselwa ukugqiba zombini peptide acid acid Ukwakhiwa kwaye ukucacisa lo mbuzo: leyo zenze monomers DNA, ngamanye amazwi, ukuba ukwakhiwa sofuzo ohambelana. Hi xikombiso, le triplet (codon) AAA kwi gene buqonda le phenylalanine acid asidi kwemolekyuli protein, kwaye ikhowudi yezofuzo iza ilingane triplet UUU kwi mRNA chain.

Intsebenziswano ye nucleotides ngexesha DNA ukuphindaphindeka

Njengoko cacisa ngaphambili, iiyunithi noshowo monomers DNA - it nucleotides. ezilandelelanayo ngqo kwi leesekethe itemplate inkqubo yokuqaphela oluncedisayo deoxyribonucleic acid mpilo. Oku kwenzeka kwi S-ibakala iiseli interphase. Ulandelelwano nucleotide neemolekyuli DNA inoveli ngamatyathanga okokoko koomama yi-Polymerase DNA enzyme kunye nomgaqo complementarity (A - C, A - C). Ukuphindaphindeka ibhekisa ngayo matrix yokuqaphela. Oku kuthetha ukuba monomers DNA kunye nesakhiwo yabo kwikhonkco lomzali asisiseko, oko itemplate iikopi ancedisayo yayo.

Oku uyakwazi ukutshintsha isakhiwo nucleotide

Hi ndlela leyi, makhe ndithi ukuba deoxyribonucleic acid - na isakhiwo ngendeb yeseli ngumongo. Kukho ingcaciso esengqiqweni: ulwazi yemfuza zigcinwe chromatin ye ngumongo, kufuneka iqhubekeke kwaye beluphindwe ngaphandle Bill. Kodwa zofuzo cellular usoloko "phantsi umpu" iimeko zokusingqongileyo. Umzekelo, loo imichiza silwe ezifana utywala, iziyobisi, radiation eqhumayo. Bonke bephela ekuthiwa mutagens, phantsi kwempembelelo apho naluphi na monomer DNA uyakwazi ukutshintsha kobume yemizimba yethu. Le ubugqwetha ngamachiza kuthiwa kuguquka point. Le rhoqo isenzeko iseli ufuzo sezingeni eliphezulu. Kwezakhi alungiswe esebenza kakuhle umsebenzi inkqubo yokulungisa iseli, kuquka isethi enqanda.

Abanye babo, ezifana enzayim isithintelo, "kunqunyulwa" i nucleotides ezimashakeleyo, polymerases kuvumela Yindibanisela monomers eqhelekileyo ligase "crosslinked" wabuyisa iinxalenye sofuzo. Ukuba indlela ngasentla, ngasizathu sithile, iseli akusebenzi kwaye ezineziphene DNA monomer uhleli molecule layo, lo guquko misho yi iinkqubo matrix amagama kunye phenotypically wabonakalaliswa ngohlobo iiproteni ngempahla etshintshiweyo, akakwazi ukwenza imisebenzi eyimfuneko obekwayo ukutya zeselula. Le yinto enkulu ezimbi, ukunciphisa iseli uzinzo kunciphisa ixesha lobomi bakhe.