Nws paub zoo tias txhua yam kev muaj sia nyob, los ntawm cov kab mob mus rau cov tsiaj uas muaj kev sib koom siab (xws li tib neeg), muaj cov cuab yeej cuab tam tshwj xeeb. Nws yog sawv cev los ntawm molecules ntawm ob hom nucleic acids: deoxyribonucleic thiab ribonucleic. Nyob rau hauv cov organic tshuaj, cov ntaub ntawv yog encoded uas kis tau los ntawm niam txiv cov neeg mus rau cov xeeb leej xeeb ntxwv thaum yug me nyuam. Hauv kev ua haujlwm no, peb yuav kawm txog cov qauv thiab kev ua haujlwm ntawm DNA thiab RNA hauv lub cell, thiab tseem xav txog cov txheej txheem hauv qab ntawm cov txheej txheem ntawm kev hloov cov khoom qub ntawm cov khoom muaj sia.
Raws li nws tau muab tawm, cov khoom ntawm nucleic acids, txawm hais tias lawv muaj qee qhov zoo sib xws, txawm li cas los xij txawv ntau txoj hauv kev. Yog li, peb yuav sib piv cov haujlwm ntawm DNA thiab RNA ua los ntawm cov biopolymers hauv cov hlwb ntawm ntau pawg kab mob. Cov lus qhia hauv kev ua haujlwm yuav pab kom nkag siab tias lawv qhov txawv ntawm qhov tseem ceeb.
Nucleic acids -complex biopolymers
Tshawb nrhiav hauv thaj chaw ntawm molecular biology uas tshwm sim thaum pib ntawm lub xyoo pua 20th, tshwj xeeb, kev txiav txim siab ntawm cov qauv ntawm deoxyribonucleic acid, tau txais kev txhawb nqa rau kev txhim kho niaj hnub cytology, noob caj noob ces, biotechnology thiab noob caj noob ces. engineering. Los ntawm qhov pom ntawm cov organic chemistry, DNA thiab RNA yog cov tshuaj macromolecular uas muaj qhov rov ua dua tshiab - monomers, tseem hu ua nucleotides. Nws paub tias lawv muaj kev sib tshuam, tsim cov chains muaj peev xwm ntawm kev sib koom ua ke ntawm tus kheej.
Cov DNA macromolecules feem ntau khi rau cov protein tshwj xeeb nrog cov khoom tshwj xeeb hu ua histones. Nucleoprotein complexes tsim cov qauv tshwj xeeb - nucleosomes, uas, dhau los, yog ib feem ntawm chromosomes. Nucleic acids tuaj yeem pom ob qho tib si hauv lub nucleus thiab hauv cytoplasm ntawm lub cell, muaj nyob rau hauv qee yam ntawm nws cov organelles, xws li mitochondria lossis chloroplasts.
Spatial qauv ntawm cov khoom ntawm heredity
Txhawm rau nkag siab txog cov haujlwm ntawm DNA thiab RNA, koj yuav tsum nkag siab meej txog cov yam ntxwv ntawm lawv cov qauv. Zoo li cov proteins, nucleic acids muaj ob peb theem ntawm lub koom haum ntawm macromolecules. Lub hauv paus qauv yog sawv cev los ntawm polynucleotide chains, qhov thib ob thiab tertiary configurations yog nws tus kheej-txhawj xeeb vim hais tias ntawm qhov tshwm sim covalent hom ntawm daim ntawv cog lus. Lub luag haujlwm tshwj xeeb hauv kev tswj xyuas qhov sib txawv ntawm cov molecules belongs rau hydrogen bonds, nrog rau van der Waals rog ntawm kev sib cuam tshuam. Qhov tshwm sim yog compacttus qauv ntawm DNA, hu ua supercoil.
Nucleic acid monomers
Cov qauv thiab kev ua haujlwm ntawm DNA, RNA, cov proteins thiab lwm cov organic polymers nyob ntawm ob qho tib si zoo thiab muaj pes tsawg leeg ntawm lawv cov macromolecules. Ob hom nucleic acids yog tsim los ntawm lub tsev thaiv hu ua nucleotides. Raws li paub los ntawm cov chav kawm ntawm chemistry, cov qauv ntawm cov khoom tsim nyog cuam tshuam rau nws txoj haujlwm. DNA thiab RNA tsis muaj kev zam. Nws hloov tawm hais tias hom kua qaub nws tus kheej thiab nws lub luag hauj lwm nyob rau hauv lub cell nyob ntawm seb muaj pes tsawg leeg nucleotide. Txhua monomer muaj peb ntu: nitrogenous puag, carbohydrate, thiab phosphoric acid residue. Muaj plaub hom nitrogenous hauv paus rau DNA: adenine, guanine, thymine thiab cytosine. Hauv RNA molecules, lawv yuav yog, raws li, adenine, guanine, cytosine thiab uracil. Carbohydrate yog sawv cev los ntawm ntau hom pentose. Ribonucleic acid muaj ribose, thaum DNA muaj nws daim ntawv deoxygenated, hu ua deoxyribose.
Ntawm ntawm deoxyribonucleic acid
Ua ntej, peb yuav saib cov qauv thiab kev ua haujlwm ntawm DNA. RNA, uas muaj qhov yooj yim spatial configuration, yuav tau kawm los ntawm peb nyob rau hauv nqe lus tom ntej. Yog li, ob lub polynucleotide strands tau tuav ua ke los ntawm kev rov ua dua hydrogen bonds tsim ntawm nitrogenous bases. Hauv cov khub "adenine - thymine" muaj ob, thiab hauv khub "guanine - cytosine" muaj peb daim ntawv cog lus hydrogen.
Cov lus sau tseg ntawm purine thiab pyrimidine hauv paus yognrhiav tau los ntawm E. Chargaff thiab raug hu ua lub hauv paus ntsiab lus ntawm complementarity. Nyob rau hauv ib qho kev sib txuas, cov nucleotides txuas ua ke los ntawm phosphodiester bonds tsim ntawm pentose thiab orthophosphoric acid residue ntawm nucleotides uas nyob ib sab. Daim ntawv helical ntawm ob txoj saw yog tswj los ntawm hydrogen bonds uas tshwm sim ntawm hydrogen thiab oxygen atoms uas yog ib feem ntawm cov nucleotides. Qhov siab dua - tertiary qauv (supercoil) - yog yam ntxwv ntawm cov DNA ntawm cov hlwb eukaryotic. Hauv daim ntawv no, nws muaj nyob hauv chromatin. Txawm li cas los xij, cov kab mob thiab cov kab mob DNA muaj cov deoxyribonucleic acid uas tsis cuam tshuam nrog cov proteins. Nws yog sawv cev los ntawm lub nplhaib-zoo li daim ntawv thiab hu ua plasmid.
DNA ntawm mitochondria thiab chloroplasts, organelles ntawm cov nroj tsuag thiab tsiaj hlwb, muaj tib yam zoo li. Tom ntej no, peb yuav pom tias cov haujlwm ntawm DNA thiab RNA txawv li cas. Cov lus hauv qab no yuav qhia peb qhov sib txawv ntawm cov qauv thiab cov khoom ntawm nucleic acids.
YRibonucleic acid
RNA molecule muaj ib tug polynucleotide strand (tshwj xeeb yog ob-stranded qauv ntawm qee cov kab mob), uas tuaj yeem nyob hauv ob qho tib si hauv lub nucleus thiab hauv cell cytoplasm. Muaj ntau ntau hom ribonucleic acids, uas txawv ntawm cov qauv thiab cov khoom. Yog li, tus tub txib RNA muaj qhov hnyav tshaj plaws molecular. Nws yog synthesized nyob rau hauv lub cell nucleus ntawm ib tug ntawm cov noob. Lub luag haujlwm ntawm mRNA yog txhawm rau hloov cov ntaub ntawv hais txog qhov muaj pes tsawg leeg ntawm cov protein los ntawm cov nucleus mus rau cytoplasm. Kev thauj mus los ntawm nucleic acid txuas cov protein monomers- amino acids - thiab xa lawv mus rau qhov chaw ntawm biosynthesis.
Thaum kawg, ribosomal RNA yog tsim nyob rau hauv lub nucleolus thiab koom nrog cov protein synthesis. Raws li koj tuaj yeem pom, cov haujlwm ntawm DNA thiab RNA hauv cellular metabolism yog ntau haiv neeg thiab tseem ceeb heev. Lawv yuav nyob ntawm seb, ua ntej ntawm tag nrho cov, nyob rau hauv lub hlwb ntawm cov kab mob uas muaj cov molecules ntawm cov tshuaj ntawm heredity. Yog li, nyob rau hauv cov kab mob, ribonucleic acid tuaj yeem ua tus nqa ntawm cov ntaub ntawv keeb kwm, thaum nyob hauv cov hlwb ntawm cov kab mob eukaryotic, tsuas yog deoxyribonucleic acid muaj peev xwm.
Kev ua haujlwm ntawm DNA thiab RNA hauv lub cev
Raws li lawv qhov tseem ceeb, nucleic acids, nrog rau cov proteins, yog cov organic tebchaw tseem ceeb tshaj plaws. Lawv khaws cia thiab xa cov cuab yeej cuab tam thiab cov yam ntxwv ntawm niam txiv mus rau cov xeeb ntxwv. Cia peb txhais qhov txawv ntawm cov haujlwm ntawm DNA thiab RNA. Cov lus hauv qab no yuav qhia cov kev sib txawv no kom ntxaws ntxiv.
| View | Nyob hauv tawb | Kev teeb tsa | Function |
| DNA | core | superspiral | preservation and transmission of hereditary information Ntxawm |
| DNA |
mitochondria chloroplasts |
circular (plasmid) | loj kis ntawm cov ntaub ntawv keeb kwm yav dhau los |
| iRNA | cytoplasm | linear | tshem tawm cov ntaub ntawv ntawm cov noob |
| tRNA | cytoplasm | secondary | thauj cov amino acids |
| rRNA | core thiabcytoplasm | linear | tsim ntawm ribosomes |
Tus yam ntxwv ntawm cov tshuaj ntawm cov kab mob tshwm sim yog dab tsi?
Nucleic acids ntawm cov kab mob tuaj yeem ua rau hauv daim ntawv ntawm ob qho tib si-stranded thiab ob-stranded helices lossis nplhaib. Raws li D. B altimore qhov kev faib tawm, cov khoom ntawm microcosm no muaj DNA molecules uas muaj ib lossis ob txoj hlua. Thawj pab pawg suav nrog herpes pathogens thiab adenoviruses, thiab thib ob suav nrog, piv txwv li, parvoviruses.
Lub luag haujlwm ntawm DNA thiab RNA cov kab mob yog nkag mus rau lawv tus kheej cov ntaub ntawv keeb kwm yav dhau los rau hauv lub xovtooj ntawm tes, ua cov kev hloov pauv ntawm cov kab mob nucleic acid molecules thiab sib sau cov protein ntau hauv cov ribosomes ntawm lub cell. Yog li ntawd, tag nrho cov cellular metabolism yog kiag li subordinated mus rau parasites, uas, sai heev multiplying, coj cell mus rau tuag.
RNA viruses
Nyob rau hauv virology, nws yog kev cai los faib cov kab mob no ua ob peb pawg. Yog li, thawj suav nrog cov tsiaj uas hu ua single-stranded (+) RNA. Lawv cov nucleic acid ua haujlwm tib yam li tus xa xov RNA ntawm eukaryotic hlwb. Lwm pab pawg muaj xws li ib leeg-stranded (-) RNAs. Ua ntej, kev hloov pauv tshwm sim nrog lawv cov molecules, ua rau cov tsos ntawm (+) RNA molecules, thiab cov, tig mus, ua tus qauv rau kev sib sau cov kab mob sib kis.
Raws li cov lus hais saum toj no, rau txhua yam kab mob, suav nrog cov kab mob, kev ua haujlwm ntawm DNA thiab RNA yog cov yam ntxwv luv luv raws li hauv qab no: khaws cia cov yam ntxwv ntawm cov kab mob thiab cov khoom ntawm cov kab mob thiab lawv txuas ntxiv mus rau cov xeeb ntxwv.
