Ubume be-DNA yenziwa ... chemical nokwakheka DNA

Abantu abaninzi baye basoloko wazibuza ukuba kutheni imiqondiso ethile ifumaneke abazali umntwana (umzekelo, umbala wamehlo, iinwele, imilo ubuso, kunye nabanye). Science singqiniwe ukuba iimpawu transfer kuxhomekeke impahla yemfuza, okanye DNA.

Yintoni i-DNA?

Okwangoku, phantsi deoxyribonucleic acid ukuqonda ezimbaxa nezintsonkothileyo elinoxanduva ekudluliseni neempawu zamafa. Le molecule afumaneka kuzo zonke iseli umzimba wethu. Le wotshi yalungiselelwa iimpawu eziphambili umzimba wethu (ngokuba uphuhliso uphawu uhambelana iproteni ethile).

Kuthetha ntoni nala? Ubume be-DNA yenziwa iikhompawundi ezinzima - nucleotides. Ngu block lwenzelwe nucleotide okanye ezimbaxa mini ukuba kubume bayo isiseko nitrogen, amasalela abantu phosphoric acid kunye iswekile (kulo mzekelo - deoxyribose).

DNA molecule kabini balahleke, apho ngamnye iziphaluka eqhagamshelwe omnye ngokusebenzisa iziseko nenayitrojini umgaqo complementarity.

Ngaphezu koko, oko kuthathwa ukuba i-DNA kuquka zofuzo - ulandelelwano nucleotide ethile onoxanduva protein yokuqaphela. Ziintoni iimpawu eekhemikhali ubume deoxyribonucleic acid na?

nucleotide

Njengoko kukhankanyiwe, iyunithi esisiseko noshowo deoxyribonucleic acid kuyinto nucleotide. Oku a entity entsonkothileyo. Kwalo nucleotide DNA elandelayo.

Xa iziko yi ezintlanu-component nucleotide iswekile (deoxyribose DNA achasene ku RNA, oluqulathe ribose). Apho ujoyine isiseko nitrogen, nto leyo uyazimela Iintlobo 5: adenine, guanine, thymine, uracil kunye cytosine. Ukongezelela, nucleotide ngalinye lakhiwa yaye acid nikunyhashe phosphoric.

Ubume be-DNA yenziwa kuphela ezo nucleotides ukuba babe iyunithi noshowo kubonisiwe.

Zonke nucleotides acwangciswe kwikhonkco kwaye landela omnye komnye. Kudweliswe ezintathu (nucleotides emithathu), zakha ulandelelwano apho triplet nganye sihambisane acid acid ethile. Ngenxa yoko a chain.

Babe kunye ngokusebenzisa unxibelelwano of iziseko nitrogen. Ulwalamano basic phakathi kwiisekethe nucleotides ngaxeshanye - hydrogen.

Oku kulungisiweyo Nucleotide asisiseko yemfuza. KumaLungelo kubume, olukhokelela ukusilela kwi Yindibanisela iiprothini nokubonakalaliswa izakhi. Ubume be-DNA yenziwa zofuzo efanayo ezibonakalisa phantse bonke abantu ukwahlula kwezinye izinto eziphilayo.

ukulungisa i nucleotide

Kwezinye iimeko, ukuba ukudluliselwa ezinzileyo ngakumbi a loguqulelo uphawu babangenagama nitrogen iyasetyenziswa. Ukubunjwa eekhemikhali DNA iyatshintsha kuthinjwe iqela imethyl (CH3). ukuguqulwa enjalo (enye nucleotide) ivumela ukuba ukuzinzisa gene ibinzana kunye nokudluliselwa neempawu iiseli intombi.

Oku "ukuphucula" lobume molecule aluchaphazeli umbutho iziseko nitrogen.

Le ukuguqulwa lisetyenziswa X-chromosome inactivation. Ngenxa yoko, kwasekwa umzimba Barr.

Kwimeko eyandileyo analysis DNA carcinogenesis ibonisa ukuba umqokozo nucleotides yathotyelwa kwimeko kwesipirithi kwi substrates ezininzi. Xa izifundo lokuqwalasela, wawuqhutywa ukuba umthombo uguquko idla ngokuba cytosine ethanol. ngexesha Ithumba Ngokuqhelekileyo inkqubo demethylation angakhuthaza inkqubo stop, kodwa ngenxa yokuntsonkotha yayo, indlela abasabela ngayo akwenziwanga.

isakhiwo DNA

Xa isakhiwo kwemolekyuli iintlobo ezimbini zezakhiwo. Uhlobo lokuqala - ulandelelwano ngokulandelelanayo ye nucleotides kwakhiwa. ukwakhiwa yabo ngokuxhomekeke kwimithetho ethile. Ukurekhoda kwi nucleotide yomoya iDNA uqala 5'-terminus ze-terminus 3'iphela. Isiphaluka sesibini ibekwe phezu koko, sakhiwe ngendlela efanayo, kuphela iimolekyuli omnye nendawo malunga kwenye, apho i-terminus 5'umxokelelwane enye nenye ibekwe malunga ekupheleni-3'le yesibini.

kweleli - DNA isakhiwo eziziisekondari. Olubangelwa bubukho iibhondi hydrogen ukusukela phakathi nucleotides alwayo. Iqhina hydrogen ezikhandelwa (thymine kuphela, guanine kunye umahluko ube umzekelo, malunga adenine umcu yokuqala - uracil okanye cytosine) phakathi iziseko ngokubambisana nitrogen. Ukuchaneka okunjalo ngenxa yokuba ulwakhiwo isiphaluka sesibini ithatha indawo ngokwesiseko lokuqala, ukuze phakathi iziseko nitrogen apho kungqamana ngqo.

Le Yindibanisela molecule

ntoni kwemolekyuli DNA kwakhiwa njani?

Kumjikelo wesiseko yayo nezigaba ezithathu:

• iziphaluka zidingo.
• Eqale synthesizing iiyunithi ukuya kwenye eentsontelo.
• Ukwandiswa evela isiphaluka sesibini ngokungqinelana umgaqo complementarity.

Xa nqanaba yokuzahlula neemolekyuli esilawulwa enqanda - DNA gyrase. Ezi enzyme swi kokutshatyalaliswa imixokelelwane hydrogen phakathi imixokelelwane.

Emva ngamatyathanga divergence kufika ezisisiseko enzyme synthesizing - DNA polymerase. ukubambelela kwayo waphawula kwindawo 5 '. Emva koko, i-enzayim lisiya ngasekupheleni-3', ngaxeshanye kuqhotyoshelwe nucleotides ezifunekayo kunye iziseko ezifanelekileyo nitrogen. Emva kokuba uluhlu kwangaphambili (terminator) ekupheleni 3 ', polymerase chain eso luqhawulwe ivela kumthombo.

Xa kwakhiwa yesekethe sokuncedisa phakathi iziseko ubuhlobo obuluqilima hydrogen, kwaye okwaziyo DNA elalisandul 'ukusekwa.

ndokufunela phi le molecule?

Ukuba lokumba ubume iiseli zomzimba, oko kunokubonwa ukuba iDNA kakhulu ifumaneka kwi kwiseli nucleus. I kernel unoxanduva ukuyilwa nkampani ezintsha, iiseli okanye clones zabo. Ngaloo ndlela ulwazi yemfuza khona apho, yahlulwe phakathi iiseli elalisandul 'ukusekwa ngokufanayo (eyenziwe clones) okanye inxalenye (kaninzi kubonwa ngexesha meiosis nesenzeko). Le ngokoyiswa Iziphumo ezingundoqo kwindawo yaphula ukuyilwa izihlunu ezitsha, nto leyo ekhokelela zofuzo.

Ukongeza, uhlobo olulodwa lwezinto ilifa eziqulethwe mitochondria. Bathi DNA yahlukile ukuba ngumongo (deoxyribonucleic acid ayo ine imilo thunzi kwaye eminye imisebenzi eziliqela).

Molecule kukodwa zibekwe zodwa kuyo nayiphi iseli lomzimba (kuba isifundo swab ezininzi ezisetyenziswayo ngokuqhelekileyo ukusuka ngaphakathi esidleleni okanye igazi). Akukho zofuzo kuphela epithelium exfoliates kunye neeseli igazi ethile (erythrocytes).

imisebenzi

Ukubunjwa kwemolekyuli iDNA imisela ekwenziweni komsebenzi walo ukudluliselwa data ukusuka kwisizukulwana ngesizukulwana. Oku kungenxa Yindibanisela iiproteni ezithile ezikhokelela ngokubonakala a kweejini (ngaphakathi) okanye phenotypic (lwangaphandle - umzekelo, umbala amehlo okanye iinwele) inkalo.

Ukudluliselwa kolwazi lwenziwa ngokusebenzisa ikhowudi yayo yemfuza. Ngokwesiseko idata zombhalo kwi ikhowudi yezofuzo, kukho uphuhliso iinkcukacha ezithile, ribosomal kunye transfer RNA. Ngamnye kubo abajongene inyathelo elingqalileyo - umthunywa RNA lusetyenziswa nokulungelelanisa iiproteni inxaxheba iimolekyuli leeprothini ribosomal ibandla, kwaye yenza liyahambisana iiproteni zothutho.

Naluphi na ukusilela ukusebenza okanye isakhiwo lwabo utshintsho kukhokelela uphazamiseko umsebenzi owenziwe, kunye ukubonakala iimpawu Nedlac (zofuzo).

DNA lukatata test ukufumanisa ubukho iimpawu ezinxulumene phakathi kwabantu.

iimvavanyo genetic

Yintoni ngoku kusetyenziswa isifundo zofuzo?

Uhlalutyo DNA isetyenziselwa ukugqiba eziliqela okanye utshintsho eziphilayo.

Isifundo sokuqala ukufumanisa ubukho, izifo bekhubazekile ilifa. izifo ezifana ziquka Down syndrome, Autism, yiMarfan syndrome.

Ukuze ubone DNA nomini nayo kufundwa. uvavanyo lukatata kukade icangcisiwe, yande ezininzi, ezomthetho ngokuyintloko, iinkqubo. Olu phando imiselwe yokuqingqa ubudlelwane yemfuza phakathi niyimigqakhwe. Amaxesha amaninzi olu vavanyo izicelo angaludlulisa ilifa xa kuthe iingxaki kunye nabasemagunyeni.