Nucleotide - yintoni na le nto? Ekwakhiweni, isakhiwo, inani nolandelelwano nucleotides kwikhonkco DNA

Zonke ukuphila emhlabeni ubunjwe iiseli ezininzi ezixhasa-odolwa kweencwadi nezinto umbutho ngendleko equlethwe ngumongo ulwazi yemfuza. It isekhona, imiliselwe kwaye idluliselwe khompawundi ezintsonkothileyo macromolecular - into nucleic acid eyenziwa iiyunithi monomer - nucleotides. akunakwenzeka ukuba zazi indima asidi acid. Stability kwezakhiwo zabo emiselwe eqhelekileyo yokusebenza ephilayo, kwaye naziphi na izinto ezinxaxhileyo kubume uya ekugqibeleni kukhokelela utshintsho kwintlangano zeselula, umsebenzi nokomzimba kunye nokufaneleka leseli jikelele.

Ingcamango a nucleotide kunye neempawu zayo

Nganye molecule ye DNA okanye RNA sakhiwe iikhompawundi ezincinci monomeric - nucleotide. Ngamanye amazwi, le nucleotides - kwiibloko zokwakha nucleic, intsebenziswano-enzyme kunye nezinye iikhompawundi ezininzi eziphilayo, nto leyo ebaluleke kakhulu ukuba iseli ngexesha ebomini bayo.

Iimpawu eziphambili zezi zinto eziyimfuneko zibandakanya:

• yokugcina ulwazi malunga ngesakhiwo iiproteins kunye neempawu ilifa;
• Lawula phezu ukukhula kunye nokuzala;
• inxaxheba ukutya kunye nezinye iinkqubo ezininzi komzimba kwiseli.

Indlela ezakhiwe ngayo nucleotides

Ethetha nucleotides, asinakukwazi kuhlala ngomba ezibalulekileyo ezifana nesakhiwo kunye nokwakheka.

nucleotide ngalinye lenziwa:

• abaseleyo sugar;
• isisekelo nitrogen;
• Iqela phosphate okanye amasalela abantu phosphoric acid.

Sinokuthi ukuba nucleotide - a organic ezimbaxa nezintsonkothileyo. Kuxhomekeka ekwakhiweni ethile kunye nohlobo neziseko nitrogen kwi nucleotide pentose isakhiwo nucleic acid nohlulwe:

• deoxyribonucleic acid okanye DNA;
• ribonucleic acid, okanye RNA.

Ukudalwa nucleic acid

Le asidi-pentose iswekile nucleic ufundwa. Le iswekile carbon ezintlanu-kwi DNA ibizwa ngokuba deoxyribose, xa RNA - ribose. molecule ngalinye pentoses athom ezintlanu carbon, ezine apho kunye ne-atom oxygen zenze isangqa-membered ezintlanu, kwaye isahlulo sesihlanu zeqela komeho-CH2.

Isikhundla atom carbon ngalinye molecule pentose zibonakaliswe yesi Arabic kunye awona (1C ', 2C', 3C ', 4C', 5c '). Ekubeni zonke iinkqubo zokufunda ulwazi zofuzo iimolekyuli acid nucleic abe directivity engqongqo, inqubo ye atom carbon kunye nelungiselelo zabo umsesane kusebenza isalathisi ukuya kwicala elichanekileyo.

Le hydroxyl Iqela le athom icarbon lesithathu kwaye sesihlanu (okanye abeBanga 3 '5') acid phosphoric eqhotyoshelweyo abaseleyo. Ulobala yesazisi eekhemikhali DNA kunye RNA iqela asidi.

I-atom carbon yokuqala (1) isiseko nitrogen eziqhotyoshelwe molecule neswekile.

Species esekela ukwakheka nitrogen

Nucleotides ye DNA iziseko nitrogen zimelwe ntlobo ezine:

• adenine (A);
• guanine (G);
• cytosine (C);
• thymine (T).

I ezimbini zokuqala kwakucingwa ukuba udidi purines, ezimbini zokugqibela - pyrimidine. Ezinto ubunzima purine pyrimidine usoloko nzima.

Nucleotides RNA iziseko nitrogen zimelwe:

• adenine (A);
• guanine (G);
• cytosine (C);
• uracil (U).

Uracil kwakunye thymine, kwisiseko pyrimidine.

Kule ncwadi zenzululwazi yaye ngokufuthi uyakwazi ukufumana ezinye iziseko leligama nitrogen - Latin (A, T, C, G, U).

iinkcukacha Greater isakhiwo eekhemikhali purines kunye pyrimidines.

Pyrimidines, oko kukuthi, cytosine, thymine kunye uracil, kubume bafanekiselwa initrogen ezimbini athom ezine carbon oyinxalenye umsesane ezintandathu membered. Wonke atom unenani wayo ukusuka ku-1 ukuya ku-6.

Purines (adenine kunye guanine) ibandakanya pyrimidine kunye imidazole okanye heterocycles ezimbini. iziseko purine molecule zimelwe initrogen ezine athom ezintlanu carbon. ingaphezulu nganye ukusuka ku-1 ukuya 9.

kwisiphumo umchiza babangenagama nitrogen kunye namasalela pentose kwakheka analogue. Nucleotide - inamehlo analogue kunye neqela phosphate.

Ukwenziwa iibhondi phosphodiester

Kubalulekile ukuqonda umbuzo ukudibanisa indlela nucleotides kwikhonkco polypeptide ukwenza acid molecule nucleic. Oku kwenzeka ngenxa imixokelelwane ebizwa ngokuba yi-phosphodiester.

Intsebenziswano ye nucleotides ezimbini unika dinucleotide. Formation of iikhompawundi ezintsha kwenzeka amafu njengoko phakathi amasalela phosphate of monomer omnye kunye nomnye pentose bond phosphodiester hydroxy kwenzeka.

Polynucleotide yokuqaphela - kuphinda phindaphindo lwesi reaction (amaxesha kwesigidi ezimbalwa). A chain polynucleotide yakhiwe ngokwenza imixokelelwane phosphodiester phakathi carbons iswekile lesithathu kwaye sesihlanu (3 'kwaye 5').

Wahlanganisa polynucleotide - yinkqubo entsonkothileyo ukuba ithatha indawo xa i-enzayim ye DNA polymerase, enika kuphela ukukhula chain kwelinye icala (3 ') kunye neqela free hydroxy.

Ubume kwemolekyuli DNA

Molecule DNA kwakunye kwiproteni kunokuba isakhiwo lokuqala, lesibini nelesithathu.

Ngokulandelelana nucleotides kwikhonkco DNA uchaza yayo ephambili isakhiwo. isakhiwo Secondary ukhandwa ngenxa imixokelelwane hydrogen, isiseko apho ukwenzeka wabeka complementarity siseko. Ngamanye amazwi, xa Yindibanisela DNA kweleli kabini izenzo njalo ethile: adenine, thymine uhambelana kwisiphaluka enye, guanine - cytosine vice versa. Izibini adenine kunye thymine okanye guanine kunye cytosine akhiwa ezimbini zokuqala kwaye ndisezintanjeni hydrogen yetyala emithathu yokugqibela. Loo compound inika amatyathanga bond nucleotide eqinileyo kunye umgama ngokulinganayo phakathi kwabo.

Ukwazi ukulandelelana nucleotides kwikhonkco DNA yi -siseko complementarity ungadluliselwa yesibini okanye supplement.

Isakhiwo neliphezulu zakhiwo DNA ukhandwa neentambo-ntathu, leyo molecule iyenza compact nabanako ngakumbi zibekwe kwisisele encinane umthamo. Umzekelo, E. ubude DNA coli mkhulu kuno-1 mm, ngoxa ubude iseli - of microns ngaphantsi kwe-5.

Inani nucleotides kwi-DNA, yaye ulwalamano lwabo oluninzi kuxhomekeke ulawulo Chergaffa (inani neziseko purine zisoloko elingana nesixa pyrimidine). Umgama phakathi nucleotides - alingana rhoqo ukuya 0,34 NM, kunye nobunzima babo eziphilayo.

Ulwakhiwo molecule RNA

RNA imelwe kwitsheyini polynucleotide enye, lisekwa iibhondi covalent phakathi pentose (ribose kulo mzekelo) kunye moiety phosphate. Ubude oko DNA elifutshane kakhulu. Ukubunjwa kweentlobo zeenqwelwana nitrogen kwi nucleotide kwaye kukho umahluko. I-RNA pyrimidine isiseko thymine endaweni uracil esetyenzisiweyo. Kuxhomekeka imisebenzi eyenziwa emzimbeni, RNA ezinokuba ndidi zintathu.

• Ribosomal (rRNA) - uya kuba ngokubanzi ukususela 3,000 5,000 nucleotides. Njengoko icandelo eyimfuneko kulwakhiwo obandakanyeka nokusekwa kweziko ebonakalayo ribosomes, iindawo omnye iinkqubo ibalulekileyo kwiseli - biosynthesis protein.
• Transport (tRNA) - iqulethe-avareji ye-75 - 95 nucleotides, wenza ukudluliselwa kwindawo ofisa acid acid polypeptide amagama in ribosome. uhlobo ngalunye tRNA (ubuncinane 40) sele ikhona kuphela kuyo ukulandelelana nucleotides okanye monomers.
• Ulwazi (RNAi) - xa nucleotide yokuqamba zahlukahlukene kakhulu. Ukudluliselwa kwenkcazelo yemfuza ukusuka DNA ribosomes, izenzo njenge template ezwi kwemolekyuli protini.

Indima nucleotides emzimbeni

Nucleotides esiseleni ukwenza iqela lemisebenzi ebalulekileyo:

• zisetyenziswa iibhloko zokwakha nucleic (nucleotide purine kunye pyrimidine series);
• inxaxheba kwiinkqubo ezininzi pathways kwelo gumbi lentolongo;
• inxalenye ATP - umthombo wamandla eziphambili iiseli;
• isenzo njengezazisi zokunciphisa nokulingana esiseleni (nad +, NADP +, isininzi, FMN);
• babe bioregulators;
• kungenziwa ingqalelo njengabathunywa yesibini extracellular kuyondelelaniswe rhoqo (umz, eminqubeni okanye cGMP).

Nucleotide - unit monomer ebumba iikhompawundi ezintsonkothileyo - asidi acid, ngaphandle apho ukutshintshwa yemfuza, ukugcinwa yayo kanye ukudlalwa. Free nucleotides zezona amacandelo aphambili inxaxheba kwiinkqubo zamandla uphawu kunye neeseli axhasayo eqhelekileyo yokusebenza yonke eziphilayo.