Acid nucleic - abagcini ukwaziswa kwezakhi zofuzo

Nucleic acid (nucleus - core) - organic compounds, okuyizinto ezihlobene ukuba khona zonke izinqubo eziyisisekelo eziphilayo ndaba. Lezi biopolymers kuthiwa lokuqala likhonjwe by F. Miescher (1968) kanye leukocyte nuclei. Ngemva kwesikhashana, acid nucleic zihlonzwe wonke amaseli abantu, izilwane kanye nezitshalo, amagciwane namagciwane. Ngakho, kwakutholakala ukuthi lezi zakhi begazi eziqukethwe bonke eziphilayo amaseli, kukhona abathwali ezinkulu zolwazi ngofuzo zinengxenye biosynthesis amaprotheni i umzimba.

Nucleic acid isethulo

acid nucleic kukhona wokufakelwa amaqembu nucleoproteins. Imikhiqizo ekupheleni hydrolysis zabo - purine futhi pyrimidine lezisekelo, pentose futhi wali band acid. Ukwakheka kwamakhemikhali ukuhlukanisa deoxyribonucleic (DNA) kanye ribonucleic acid (RNA). Isakhiwo DNA ifakiwe monosaccharide - deoxyribose, e-RNA - ribose. Lezi zinto zehlela ihluke nomunye elisekela nitrogen, isakhiwo zishintshe, kwasendaweni yeselula, kanye nemisebenzi.

Compounds-molecule ehlanganisa purine noma isizinda pyrimidine kanye pentose (ribose, deoxyribose), ngokuthi nuklozidami. Isihloko nuleozida kunqunywa kwakwakhe nitrogen okuhlanganisa e oyiyo. Ngokwesibonelo, nucleoside okubandakanya i-adenine ngokuthi adenosine, i-guanine ne - guanosine, cytosine - cytidine, uracil - uridine, ne-thymine - thymidine. Kuye carbohydrate ezakha molecule ukuhlukanisa rubonukleozidy futhi deoxyribonucleosides.

Ngaphandle lezisekelo nitrogen eziyisisekelo, nucleic acid   namagama amaningi   nalokho okubizwa ngokuthi base ezincane yochungechunge purine kanye pyrimidine (1-methyladenine, dihydrouracil, 1-methylguanine, 3 methyluracil, pseudouridine et al.).

Nucleotide kukhona esters phosphate ka nucleosides. I-molecule siqukethe purine nucleotide noma pyrimidine lezisekelo, pentose (ribose noma deoxyribose) futhi wali band acid ezisalayo oluhlanganisa kuya kwelesihlanu noma wesithathu athomu Carbo pentoses.

Nucleic acid lokuphatselene nesakhiwo nemsebenti.

I-nucleotide ngamanye akuhlanganisileyo kuleli fomu likaNkulunkulu, tri-, tetra-, penta-, hexa, hepta futhi polynucleotides, isb acid nucleic. acid nucleic yakhiwa ezinkulungwaneni noma ama-nucleotide ngabanye ukuthi nempumalanga kuhlangane yiqembu hydroxyl, etholakala eduze athomu 3'-th Carbo pentose elilodwa nucleotide nge asalile wali band acid ukuthi iseduze 5 th athomu Carbo pentose we nucleotide esilandelayo.

DNA ukwaziswa okuyinhloko zofuzo zawo wonke ophilayo eziphilayo. Ezintweni eziningi eziphilayo ngaphandle lamagciwane, ke itholakala le kuyi-nucleus yengqamuzana. Inani kancane acid is bagxila kule mitochondria futhi chloroplast.

acid Ribonucleic sezihlonziwe cishe kuwo wonke ingxenyenamba cell. Inani enkulu RNA is bagxila izingxenye ribonucleoprotein - ribosomes. Kufanele ukuthi iningi RNAs eziqukethwe cytoplasm, futhi% 10-15 kuphela kuyingxenye ikhenela.

RNA esekelwe kwasendaweni yeselula, umsebenzi begazi, isisindo yamangqamuzana ihlukaniswe ezintathu izinhlobo: ribosomal, ezokuthutha kanye-matrix.

RNA Ribosomal isebenze elimbudumbudu cytoplasmic ribosomes lapho ngokuqinile nakanjani amaprotheni. Basuke izimpawu okusezingeni eliphezulu isisindo yamangqamuzana ezinto eziphilayo. Ezokuthutha RNA zitholakala ngokuyinhloko amaseli hyaloplasm, uketshezi zenuzi mitochondria futhi chloroplast. Banezinhliziyo ongaphakeme isisindo yamangqamuzana (40 eziyinkulungwane. Daltons). umsebenzi ngokuyinhloko ukuthuthwa isebenze amino acid esuka acid acid eziyinkimbinkimbi - AMP enzyme esizeni amaprotheni zamagama, okungukuthi, ukuba ribosomes. Ukucwaninga kososayensi luye lwabonisa ukuthi acid ngalinye acid inezidingo tRNA zayo ngazinye. Okwamanje, kunezinhlobo ezingaphezu kuka-60 zama-ukudluliswa RNA.

Isilayezi RNA (isithunywa RNA). Ngalinye elithwala mRNA ngesikhathi zamagama nucleus ithola imininingwane ezintweni DNA nokudluliswa kwalo kuya ribosomes lapho lwenteke amaprotheni biosynthesis.