Nucleic acids - lub keepers ntawm kev tshuaj ntsuam genetic ntaub ntawv

Nucleic acid (nucleus - cov tub ntxhais) - organic tebchaw, uas yog txuam nrog rau lub hav zoov ntawm tag nrho cov yooj yim dab ntawm nyob teeb meem. Cov biopolymers yog thawj qhia los ntawm F. Miescher (1968) nrog leukocyte nuclei. Ib me ntsis tom qab, cov nucleic acids tau teev rau hauv tag nrho cov hlwb ntawm tib neeg, tsiaj txhu thiab nroj tsuag, microbes thiab kab mob. Yog li, nws twb muaj pov thawj hais tias cov lom tebchaw muaj nyob rau hauv tag nrho cov kab mob hlwb, yog lub ntsiab nqa khoom ntawm raws roj ntsha ntxiv, yog muab kev koom tes nyob rau hauv lub biosynthesis ntawm cov nqaijrog ntawm ib tug kab mob.

Nucleic acid kev nthuav qhia

Nucleic acids yog prosthetic pab pawg nucleoproteins. Lub kawg khoom ntawm lawv hydrolysis - purine thiab pyrimidine bases, pentose thiab phosphoric acid. Cov tshuaj nyob tus yeees paub qhov txawv deoxyribonucleic (DNA) thiab ribonucleic acid (RNA). Tus qauv ntawm DNA yog muaj monosaccharide - deoxyribose, nyob rau hauv RNA - ribose. Cov tebchaw txawv los ntawm txhua lwm yam nitrogenous bases, ntawm cov qauv ntawm cov molecules, cellular localization, raws li zoo raws li kev tso cai.

Tebchaw molecule muaj purine los yog pyrimidine puag thiab tus pentose (ribose, deoxyribose), hu ua nuklozidami. Title nuleozida txiav txim nitrogenous compound uas muaj xws li hauv nws cov qauv. Piv txwv li, ib tug nucleoside uas muaj xws li adenine hu ua adenosine, guanine - guanosine, cytosine - cytidine, uracil - uridine, thymine - thymidine. Nyob rau hauv lub carbohydrates tias ua li tus molecules paub qhov txawv rubonukleozidy thiab deoxyribonucleosides.

Dhau li yooj yim nitrogenous bases, nucleic acid   muaj ntau   thiab thiaj li hu me puag ntawm lub purine series thiab lub pyrimidine (1-methyladenine, dihydrouracil, 1-methylguanine, 3 methyluracil, pseudouridine li al.).

Nucleotides yog phosphate esters ntawm nucleosides. Cov qauv muaj ib tug nucleotide purine los yog pyrimidine bases, pentose (ribose los yog deoxyribose) thiab phosphoric acid residue uas binds mus rau lub thib tsib los yog thib peb atom Carbo pentoses.

Nucleic acid qauv thiab muaj nuj nqi.

Tus neeg nucleotides yog koom ua ke nyob rau hauv daim ntawv no di-, peb, tetra-, penta-, Hexa, hepta thiab polynucleotides, i.e. nucleic acids. Nucleic acids uas yog tsim los ntawm cov pua pua los yog txhiab ntawm ib tug neeg nucleotides uas yog koom ua ke los ntawm ib tug hydroxyl pab pawg neeg, nyob ze ntawm lub 3'-th atom Carbo pentose ntawm ib tug nucleotide nrog residual phosphoric acid uas yog nyob ze ntawm lub 5 th atom Carbo pentose ntawm lub tom ntej no nucleotide.

DNA yog thawj caj khoom siv ntawm tag nrho cov nyob lom systems. Nyob rau hauv cov kab mob tsuas yog cov kab mob thiab cov kab mob, nws yog ib ncig nyob rau hauv lub cell nucleus. Ib me ntsis nyiaj ntawm cov acid yog feeb meej nyob rau hauv lub mitochondria thiab chloroplasts.

Ribonucleic acids tau lawm tias nyob rau hauv yuav luag txhua txhua cell feem. Qhov loj tshaj npaum li cas ntawm RNA yog feeb meej nyob rau hauv ribonucleoprotein Cheebtsam - ribosomes. Nws yuav tsum tau hais tias feem ntau ntawm RNAs muaj nyob rau hauv lub cytoplasm, thiab tsuas yog 10-15% yog ib feem ntawm lub noob pob kws.

RNA raws li cellular localization, lom muaj nuj nqi, molecular yuag muab faib ua peb yam: ribosomal, thauj thiab matrix.

Ribosomal RNA laus nyob rau hauv cytoplasmic granules ribosomes qhov twg lawv muaj nrees ua txhua yam rau cov protein ntau. Lawv tsiag ntawv los ntawm high molecular ceeb thawj. Thauj RNA muaj nyob mas nyob rau hauv lub hlwb hyaloplasm, lub nuclear kua nyob rau hauv mitochondria thiab chloroplasts. Lawv muaj ib tug uas tsis muaj molecular ceeb thawj (40 txhiab. Daltons). Lawv lub ntsiab muaj nuj nqi yog cov thauj ntawm tshuab txais amino acids los ntawm cov amino acid complex - AMP enzyme mus rau lub site ntawm protein synthesis, ie, mus rau lub ribosomes. Kev tshawb fawb pom tau hais tias txhua amino acid nws muaj nws tus kheej ib tug neeg tRNA. Tam sim no, muaj ntau tshaj 60 hom ntawm hloov lwm lub tsev RNA.

Cov tub txib RNA (tub txib RNA). Txhua mRNA molecule thaum lub sij hawm synthesis nyob rau hauv lub nucleus tau txais ntaub ntawv los ntawm DNA thiab kev hloov tsheb mus rau lub ribosomes qhov twg nws yog siv nrog protein biosynthesis.