Yini ehlanganisiwe ushukela DNA? lezisekelo Chemical isakhiwo DNA

Yeka ukuthi kujabulisa kanjani ukubukela efanayo nendlela nomunye kukhona abazali nezingane. Noma, kunalokho, ihluke kakhulu, futhi kwafika abafowethu nodade, futhi kusukela umama nobaba. Bubangelwa yini futhi yini sithembele kuyo? Yini izakhiwo banesibopho kulondolozwe, ukuhlanganisa, ukudluliswa kanye ukubonakaliswa izimpawu inzalo kubazali babo?

Lokho indima kungokwalabo acid nucleic akha chromosome. Lokho abayikho molecule imisebenzi zonke izinqubo ezihlobene ufuzo futhi ukushintshashintsha. kungumsebenzi okubalulekile Yilokhu okungokwakho molecule e-DNA.

Umlando kwatholakala acid nucleic

Kwaphela isikhathi eside mayelana la mangqamuzana alwaziwa. Nokho, ngo-1869, usosayensi kusuka ucwaningo Miescher wathola nenye i-DNA ne-RNA, bese wakwazi ukuthi kuqinisekiswe basonta acid. Wakwenza lokhu ngokutadisha zamangqamuzana amhlophe egazi ubomvu.

Kusukela ngaleso sikhathi waqala isifundo kakhulu lezi zakhi. Ososayensi abaningi baye bazama ukunquma Ukwakheka kwamakhemikhali of DNA ne-RNA. Ukuze uqonde ubuntu babo, isakhiwo kanye nohlobo indima begazi. A umnikelo omkhulu lokhu eyenziwe abantu ezifana:

• A. N. Belozersky.
• Thomas Morgan.
• K. Bridges.
• A. Meller.
• G. de Vries.
• A. Sturtevant.
• A. Nadson.
• A. S. Serebrovsky.
• NP Dubinin.
• TS Filippov nabanye.

Esikhathini kusuka ngo-1900 kuya namuhla ke siye sacacisa ubunjalo acid nucleic, amakhemikhali elisekela isakhiwo DNA, izici zayo futhi ukubaluleka kwezinto eziphilayo. okutholakele Kuye kwenziwa, okuvumela ukuba sicabangele le isisekelo-molecule jikelele wakho konke ukuphila.

Ucwaningo emkhakheni wokusebenza kwezakhi zofuzo baye bavumela ukusungula ubuhlobo phakathi kwe-DNA futhi chromosome ufuzo, wokufunda isimiso sezakhi zofuzo izidalwa eziningi eziphilayo. Kwakubalulekile ngokuba ukuqonda iyunithi izilwane zasendle, izindlela zayo zokusebenza.

Futhi, ukwakheka amakhemikhali-chromosome sekutholakale. Kwatholakala ukuthi ngesisekelo - a nucleic acid-molecule kokuba isakhiwo esithile.

DNA: izici jikelele

Okulotshiweyo igama isifinyezo Okugcwele - deoxyribonucleic acid. Njengoba sihambisana nale acid RNA libhekisela eziningi nucleic. Wathola igama layo ngoba i-DNA engena ushukela. Igama layo - deoxyribose.

Ukwakheka kwamakhemikhali of DNA ne-RNA zifana kakhulu, umehluko njengoba isikhathi ikakhulukazi carbohydrate ukwakha i-molecule. Ngo-RNA kuyinto ribose.

Ngokuvamile, i-deoxyribonucleic acid molecule a double balahleke macromolecule eziyinkimbinkimbi kokuba isisindo yamangqamuzana Ukwakheka omkhulu futhi zihlukahlukene. Ngakho-ke, iningi compounds yesithombe ingcaca ine uhlobo imicu emibili, lohlanganisiwe izinyathelo transverse - izibopho.

Ngo-1953, Chargaff nozakwabo ukwazile ukwambula ngokugcwele Sakhiwo sangekhatsi kanye nokwakheka kwe-molecule, okuyinto kwakubaluleke kakhulu lonke we-molecular biology nesayensi bebonke. Kwacaca ukuthi ushukela ezinhlanu-carbon abandakanya i-DNA elisekela (pentose), purine futhi pyrimidine elisekela futhi orthophosphoric acid izinsalela.

Kungenzeka ukuba ningabi nje kuphela okunye wokufunda kakhulu isakhiwo enkompolo, kodwa futhi ukutadisha izakhiwo, ngokomzimba futhi amakhemikhali. Iqhaza begazi futhi sibalulekile umzimba yathathwa njengoba ayisisekelo, jikelele kanye ethize impahla ngayinye.

amakhemikhali ukwakheka

Uma elichaza kwangaphakathi Ukwakheka atomic yamangqamuzana we nucleic acid amangqamuzana, kungenzeka ukuhlonza izinhlobo eziningana eziyisisekelo ezibangela:

• pentose - deoxyribose (carbohydrate kuyinto monosaccharide);
• lezisekelo organic - purine (i-adenine futhi guanine) pyrimidine (cytosine ne thymine);
• wali band acid izinsalela ngezibopho khulula.

Lokhu, ngokuvamile, zonke chemical izisekelo isakhiwo DNA. Enye into ukuthi inhlanganisela yazo zonke lezi zingxenye akulula, kodwa kuyinqubo eyinkimbinkimbi futhi eyingqayizivele. Ngakho, oxhumene deoxyribose, isizinda kanye wezinto ezingaphili acid ezisalayo ndawonye bakha nucleotide. Kuyinto omunye ukulandelanisa nucleotide, futhi ithuthukisa lonke isakhiwo engqamuzaneni iyonke.

Abahlukile ezilandelana ngayo base organic uzobe elise elilodwa ngemuva nezinye futhi maqondana uchungechunge eduze. Ukulandelana nucleotide kwakhiwa ngezimiso ezithile, eyisikhulu phakathi okuyinto complementarity (esiqinile nesikhathi purine futhi izingxenye pyrimidine). Lokhu kuvumela wonke umuntu ukuba zaso zofuzo, ehlukile, isegazini futhi ijulile eqondene.

Phenotype kubonakala ngesimo ukulandelana nezakhi ezihlukene ngokuphelele, ukuthi abekho abantu ezimbili ezifanayo (ngaphandle kwamawele afana ncimishi), timphawu letehlukene yokubukeka.

Isakhiwo DNA kuhlanganisa noma iyiphi ushukela?

Isisekelo sanoma ibuphi udaba eziphilayo - a ama-athomu carbon chain. Molecule ye-DNA akuyona ngaphandle. Phela i-DNA ingena ushukela, okungukuthi, it siqukethe ukulandelana kwama-atom ezinhlanu carbon, ezihlanganiswe isakhiwo eyindilinga. Lokhu-molecule efanayo uphazamiseka i ibhuloho omoya-mpilo angaphakathi umjikelezo jikelele.

Ukwakheka kwamakhemikhali ushukela uwukubonakaliswa le ndlela elandelayo enokwehla: C ₅ H ₁₀ O _4. Lokhu-molecule - aldopentoza ehlanganisa ama-athomu carbon ezinhlanu, basonta ku-loop. Ngaphezu kwalokho, omunye athomu esikuziphathimandla esikhundleni iqembu hydroxyl iqukethe hydrogen nje, ngalokho kwaba khona isiqalo ezifana "deoxy" esihlokweni ushukela, okungukuthi, ngaphandle oksijini.

Ukwakheka kwamakhemikhali ushukela watholwa futhi wafunda Fibusom Lieven, abavule isakhiwo sonke nemvelo amakhemikhali kwakwakhe 1929.

Base-molecule

lezisekelo Organic kuthiwa ingxenye DNA nucleic acid zingahlukaniswa ngamaqembu amabili main.

1. Purine - izakhiwo eziyinkimbinkimbi ezakhiwe ezimbili lomjikelezo carbon - ezinhlanu-membered futhi ayisithupha membered. Lezi zihlanganisa i-adenine futhi guanine, okuyizinto ongumphelelisi isisekelo pyrimidine sakhiwa deoxyribonucleic acid.
2. Pyrimidine - eziyisithupha-membered carbon izindandatho. Lokhu kuhlanganisa ne-thymine ne-cytosine.

Ngakho, kubonakala sengathi ingxenye ushukela DNA futhi isisekelo axhumene futhi zixhunywe ihlangane ne olukhulu of wali band acid. Zonke ndawonye uphendulela nucleotide. Isakhiwo jikelele kabili balahleke DNA nucleotide uxhumano nomsebenzisi bodwa ngokusho kokubusa complementarity: metal adenine ihambisane ne-thymine oluhambisana, i-guanine ne futhi - cytosine.

Izinhlobo isibopho phakathi izinhlayiya

Izinhlobo ezinkulu ubudlelwano phakathi ingxenye izakhiwo DNA kanje:

• hydrogen;
• covalent polar;
• amabutho aphakathi okudonsa;
• UVahan der Waals nokuxhumana.

Lokhu kukuvumela ukuba kabili balahleke isakhiwo khona conformations ezintathu:

• eyinhloko - ukulandelanisa komugqa nucleotide;
• yesibili - ngamunye lokuluhlaza helically olusontekile futhi ezimbili eceleni komunye;
• ephakeme - eziyinkimbinkimbi globule conformational kakhulu engqamuzaneni Helical.

Ngakho yokuthi ingxenye DNA engena izinsalela ushukela, isizinda, futhi acid ngesisekelo isimo sawo futhi inhlabathi ukuze kuqalise ukusebenza eziningi ekusebenzisaneni kanye kumiswa izibopho zamakhemikhali.

Inani DNA eziphilayo

Zikhona amaphuzu abaluleke kakhulu eziningana:

1. Ama-molecule kubhekwe acid afakiwe ukwakheka kwamakhemikhali chromosome ukuthi ukuthola zonke izinto eziphilayo.
2. DNA - ngesisekelo synthesis eziyinkimbinkimbi polypeptide amaketanga obhekene esephepheni kanye ne-transmission zezici sitholwa njengefa.
3. Deoxyribonucleic acid - isisekelo umbhalo, okuyi primary RNA zamagama, amaprotheni kamuva.

izinqubo ezinjalo zenzeka zonke izinto eziphilayo. Lokhu kuvumela le sakhiwo ngokuthi iyunithi jikelele wazo zonke izinto eziphilayo.

ukuzandisa molecule

Le nqubo simele kabili molecule ye-DNA, okwenzeka angesabi nge bachitha amandla ezintweni eziphilayo. Isakhi esiyinhloko kulokhu - DNA polymerase, i catalyzing enzyme kanye nokulawula wonke zamagama.

Ukufanisana Iphuzu liwukuthi ngamunye imicu engqamuzaneni ihlukaniswe futhi liye laphindeka kabili ukulandelana yayo eqondile. Inqubo okuholela ukhiqiza amangqamuzana omoya ezimbili ezintsha DNA ngamunye equkethe olulodwa polypeptide uchungechunge ubudala, kanye nesesibili nhlobo entsha, zakhiwe ngokwemigomo isimiso complementarity.

Inqubo Value - ukuhlinzeka nenzalo ukwaziswa kwezakhi zofuzo lilonke.