Namuhla sizokhuluma ngakho izisekelo ze-nitrogen. Yilezo eziqukethe imininingwane yezofuzo futhi zakhiwe ngama-purines amabili nama-pyrimidine amabili. Ama-purines aziwa ngegama le-adenine ne-guanine, kuyilapho ama-pyrimidine aziwa ngegama le-thymine ne-cytosine. ITroj kuma-fairies ibaluleke kakhulu kwi-DNA yomuntu.
Ngakho-ke, sizonikezela le ndatshana ukukutshela konke odinga ukukwazi mayelana nezisekelo ze-nitrogen, izici zazo nokubaluleka kwazo.
Ama-acid enucleic
Uma sikhuluma ngama-nucleic acid sibhekisa kuma-biomolecule ayi lezo eziqukethe imininingwane yezofuzo. Zingama-biopolymers anesisindo esiphakeme ngokwanele samangqamuzana futhi akhiwa ngamanye amayunithi amancane akhiwe futhi aziwa njengama-nucleotide. Uma siyihlaziya ngokubuka komtholampilo, ama-nucleic acid angama-molecule amakhulu akhiwa ngama-polymers alandelanayo ama-nucleotide. Wonke ama-polymers axhunywe yizibopho ze-phosphate ester ngaphandle kwesikhathi.
Kulokhu, ama-acid e-nucleic ahlukaniswe nge-deoxyribonucleic acid etholakala ihlala ku-nucleus yamaseli nakwezinye i-organelles ne-ribonucleic acid etholakala ku-cytoplasm. Akhiwe ngamaketanga amade ama-nucleotide axhumene namaqembu e-phosphate. Alukho uhlobo lwesikhathi olutholakele phakathi kwalezi zixhumanisi. Ama-molecule amakhulu kakhulu akhiwe ngamakhulu ezigidi zama-nucleotide esakhiweni esisodwa se-covalent. Lokhu kungenxa ye- izinga le-polymerization phakathi kwama-nucleotide lingaphakama kakhulu.
Ngendlela efanayo, amaprotheni esiwadlayo ekudleni nawo angama-polymer aqondaniswe nama-amino acid. Lokhu kushoda kwezikhathi ezithile kubangela ukuba khona kolwazi. Ososayensi bakutholile lokho ama-nucleic acid ayindawo yokugcina imininingwane yawo wonke ama-amino acid ukulandelana kwawo wonke amaprotheni weseli. Kuyaziwa ukuthi kunokuhlobana phakathi kokulandelana kokubili, okuvezwa ngokusho ukuthi ama-nucleic acid kanye namaprotheni angama-collinear. Incazelo yakho konke lokhu kuhlangana yaziwa njengekhodi yofuzo. Ikhodi yezofuzo iyona ebeka ukulandelana kwama-nucleotide ngaphakathi kwe-nucleic acid ehambelana ne-amino acid ephrotheni.
Kumele kukhunjulwe ukuthi yizinhlayiya ezinokwaziswa kofuzo kwezinto eziphilayo futhi ezibhekene nokudluliswa kwazo njengefa.
Izisekelo ze-nitrogen
Ukwazi ukwakheka kwama-nucleic acid kusivumele ukuthi sifunde kabanzi ngekhodi yezakhi zofuzo yomuntu. Ngenxa yalokhu, siyayazi indlela nokulawulwa kwamaprotheni synthesis futhi indlela yokudluliswa kolwazi lofuzo kusuka kuma-stem cells kuya kumaseli endodakazi.
Yilapho ukubaluleka kwezisekelo ze-nitrogenous kuqala ukungena khona. Futhi kunezinhlobo ezimbili zama-nucleic acid, njengoba sishilo ngenhla. Zivele zehluke phakathi kwazo ngoshukela eziwuphethe. Ngakolunye uhlangothi sine-deoxyribose futhi ngakolunye uhlangothi i-ribose. Zihlukaniswa futhi nezisekelo ze-nitrogen ezikuzo. Endabeni ye-DNA, sinefayela le- i-adenine, i-guanine, i-cytosine, ne-thymine. Ngakolunye uhlangothi, ku-RNA sinefayela le- i-adenine, i-guanine, i-cytosine, ne-uracil. Umehluko ukuthi ukwakheka kwamaketanga ezisekelo ze-nitrogen kuhlukile kwi-DNA ne-RNA. Ngenkathi ikwi-DNA ziyimicu ephindwe kabili, kwi-RNA iyicu elilodwa.
Incazelo kanye nezinhlobo zezisekelo ezine-nitrogen
Siyazi ukuthi izisekelo ze-nitrogen yizo eziqukethe imininingwane yezofuzo. Ngenkathi izisekelo ze-puric ne-pyrimidine zinamakha futhi ziyisicaba. Lokhu kubalulekile uma sibheka ukwakheka kwama-nucleic acid. Futhi kufanele ngikhumbule ukuthi izisekelo ze-nitrogen azincibiliki emanzini futhi zingasungula ukuhlangana okuthile kwe-hydrophobic phakathi kwazo. Lokho wukuthi, azikwazi ukuhlanganiswa ndawonye.
Lezi zici izisekelo ze-nitrogen ezisebenzele ukuzinzisa ukwakheka okuyizinhlangothi ezintathu kwama-nucleic acid akha i-DNA. Izisekelo ze-nitrogen zihlala zimunca ukukhanya futhi lapho zikububanzi be-ultraviolet spectrum ye-electromagnetic phakathi kwamanani we-250-280nm. Le mpahla isetshenzisiwe selokhu yatholwa ososayensi ukufundelwa nokwenza i-quantification.
Izisekelo ze-puric zisekelwe kwindandatho yePurine. Ziyakwazi ukubonwa njengoba ziyi-kite system enama-athomu ayi-9, ama-5 awo ayi-carbon kanti ama-4 awo angama-nitrogen. I- I-Adenine neGuanine zakheka nge-purine. Izisekelo ze-Pyrimidine nitrogenous zisekelwe kwindandatho ye-pyrimidine. Luhlelo oluyisicaba olunama-athomu ayisithupha, ama-6 awo angamakhaboni kanti amanye ama-4 angama-nitrogen.
Izisekelo eziguquliwe nama-nucleosides
Izisekelo ze-pyrimidine zonakaliswe ngokuphelele emanzini, isikhutha kanye ne-urea. Ngaphezu kwezisekelo ze-purine ne-pyrimidine esixoxe ngazo, singathola nezisekelo eziguquliwe. Izisekelo eziguqulwe kakhulu yi-5-methylcytosine, 5-hydroxymethylcytosine, ne-6-methyladenine, exhunywe ekulawulweni kwenkulumo ye-DNA. Ngakolunye uhlangothi, nathi sinakho I-7-methylguanine ne-dihydrouracil eyingxenye yesakhiwo se-RNA, ngoba zine-uracil.
Ezinye izisekelo eziguqulwa njalo yiHypoxanthine neXanthine. Bangama-metabolic intermediates angumkhiqizo wokuphendula kwe-DNA ngezinto ze-mutagenic.
Njengama-nucleoside, ayinyunyana yesisekelo sepentose esenzeka ngesibopho se-glycosidic phakathi kwekhabhoni yelinye le-ribose noma i-deoxyribose ne-nitrogen yesisekelo se-nitrogen. Endabeni yama-pyrimidine abopha nge-nitrogen 1, ngenkathi kuma-purines abopha nge-nitrogen 9. Kumele kucatshangwe ukuthi kule nyunyana i-molecule yamanzi ilahlekile.
Ososayensi bazama ukugwema ukudideka esiqeshini segama lama-nucleosides nama-nucleosides ngakho-ke, Izinombolo ezilandelwa i-apostrophe ziqokwa lapho kukhulunywa ngama-athomu epentose. Ngale ndlela, ingahlukaniswa kuleso se-nitrogenous base.
Ngiyethemba ukuthi ngalolu lwazi ungafunda kabanzi ngezisekelo ze-nitrogenous kanye nezici zazo.