Yuav ua li cas yog muaj nyob rau hauv lub DNA qab zib? Tshuaj bases ntawm cov DNA qauv

Yuav ua li cas amazing mus saib yuav ua li cas zoo ib yam li txhua lwm yam yog cov niam txiv thiab cov me nyuam. Los yog, on qhov tsis tooj, txawv heev los ntawm, thiab cov kwv tij thiab cov muam, thiab los ntawm niam thiab txiv. Vim li cas nws tshwm sim thiab hais li cas rau nws nyob ntawm seb? Yuav ua li cas lug yog lub luag hauj lwm rau lub preservation, consolidation, hloov thiab qhia cov tsos mob tshwm nyob rau hauv lub zag ntawm lawv niam lawv txiv?

Hais tias lub luag hauj lwm yog rau cov nucleic acids uas tsim chromosomes. Hais tias lawv yog molecules uas ua lub zog ntawm tag nrho cov dab muaj feem xyuam rau caj thiab variation. Tshwj xeeb prerogative rau no belongs rau DNA molecules.

Keeb kwm ntawm lub foundations ntawm nucleic acids

Rau ib ntev lub sij hawm txog cov kev molecules yog tsis paub. Txawm li cas los, nyob rau hauv 1869, ib tus paub txog los ntawm kev tshawb fawb Miescher pom ib tug sib tov ntawm DNA thiab RNA, thiab ces twb tau tsim kom muaj hais tias lawv yuav mus rau acids. Nws tau ua qhov no los ntawm kev kawm cov ntshav dawb nyob rau hauv paug.

Txij thaum ntawd los pib intensive kev tshawb ntawm cov tebchaw. Muaj ntau zaum tau sim los mus txiav txim cov tshuaj muaj pes tsawg leeg ntawm DNA thiab RNA. Yuav kom to taub lawv qhov, qauv thiab qhov xwm ntawm tus lom lub luag hauj lwm. Ib tug zoo pab rau qhov no los ntawm cov neeg zoo li raws li:

• A. N. Belozersky.
• Thomas Morgan.
• K. txuas hniav.
• A. Meller.
• G. de Vries.
• A. Sturtevant.
• G. A. Nadson.
• A. S. Serebrovsky.
• NP Dubinin.
• TS Filippov thiab lwm tus neeg.

Nyob rau hauv lub sij hawm ntawm 1900 rau hnub no nws tau clarified qhov xwm ntawm nucleic acids, tshuaj bases ntawm DNA qauv, nws cov nta thiab lom tseem ceeb. discoveries tau ua, uas peb xav txog qhov no molecule universal lub hauv paus ntawm tag nrho lub neej.

Kev tshawb fawb nyob rau hauv lub teb ntawm noob caj noob ces tau tso cai los tsim kom muaj txoj kev sib raug ntawm cov DNA thiab cov genome chromosomes, rau decipher lub caj code ntawm ntau nyob creatures. Nws yog ib qho tseem ceeb rau qhov kev nkag ntawm cov tsiaj qus chav tsev, nws ua hauj lwm mechanisms.

Tsis tas li ntawd, cov tshuaj nyob tus yeees ntawm cov chromosome tau lawm tias. Nws twb pom tias lub hauv paus ntawm - ib tug nucleic acid molecule muaj ib lub qauv.

DNA: general yam ntxwv

Tag nrho cov ntawv tseem ceeb tsiaj ntawv lub npe - deoxyribonucleic acid. Nrog rau qhov no RNA acid yog hais txog ib tug xov tooj ntawm nucleic. Txais nws lub npe vim hais tias ntawm cov DNA nkag mus rau hauv qab zib. Nws lub npe - deoxyribose.

Cov tshuaj nyob tus yeees ntawm DNA thiab RNA yog heev uas zoo sib xws, qhov txawv li lub sij hawm feem ntau nyob rau hauv carbohydrate txoj kev molecule. Nyob rau hauv RNA yog ribose.

Nyob rau hauv dav dav, lub deoxyribonucleic acid molecule yog ib tug muab ob npaug rau tso tseg txoj macromolecule muaj ib tug molecular ceeb thawj los ntawm enormous thiab varied muaj pes tsawg leeg. Yog li ntawd, feem ntau ntawm cov sib txuas ntawm cov duab duab muaj rau hauv daim ntawm ob strands, lub neej coj transverse kauj ruam - bonds.

Nyob rau hauv 1953, Chargaff thiab nws cov npoj yaig muaj peev xwm ua siab qhia lub internal qauv thiab muaj pes tsawg leeg ntawm lub molecule, uas yog ntawm kuj zoo kawg tseem ceeb rau tag nrho ntawm molecular biology uas thiab science nyob rau hauv feem ntau. Nws los ua khees tias nyob rau hauv lub tsib-carbon qab zib xws li DNA bases (pentose), purine thiab pyrimidine bases thiab orthophosphoric acid residues.

Nws yog ua tau tsis tsuas mus rau ntxiv decipher lub heev tus qauv ntawm lub compound, tab sis kuj yuav kawm txog cov khoom, lub cev thiab tshuaj. Lub lom lub luag hauj lwm thiab tseem ceeb rau tus kab mob twb khaws raws li ib tug yuav tsum muaj, universal thiab ib qho rau txhua substance.

tshuaj nyob tus yeees

Yog hais tias tuab puab atomic thiab molecular muaj pes tsawg leeg ntawm lub nucleic acid molecules, nws tseem tau mus qhia ob peb theem pib hom ntawm lub tebchaw:

• pentose - deoxyribose (carbohydrate yog ib tug monosaccharide);
• organic bases - purine (adenine thiab guanine) pyrimidine (cytosine thiab thymine);
• phosphoric acid residues nrog dawb bonds.

Qhov no, nyob rau hauv Feem ntau, tag nrho cov tshuaj bases ntawm cov DNA qauv. Ib qho ntxiv uas yog hais tias ib tug ua ke ntawm tag nrho cov Cheebtsam yog tsis yooj yim, tiam sis yog ib txoj thiab cim txheej txheem. Yog li, interconnected deoxyribose, puag thiab inorganic acid residue ua ke tsim tau ib nucleotide. Nws yog ib tug ntawm cov nucleotide sequences, thiab muaj tag nrho cov qauv ntawm cov molecule raws li ib tug tag nrho.

Cim yog ib theem zuj zus nyob rau hauv uas lub organic puag yuav tau nyob ib qab rau lwm yam thiab nyob rau hauv relation mus nyob ib sab saw. Lub nucleotide ib theem zuj zus twb ua tau lub tsev raws li cov ntsiab cai, Hmoob cov uas yog complementarity (nruj conformity purine thiab pyrimidine Cheebtsam). Qhov no pub rau txhua tus tib neeg muaj nws caj code, ib tug tshwj xeeb, tseem ceeb thiab sib sib zog nqus-meej.

Phenotype yog manifested nyob rau hauv daim ntawv ntawm ib tug succession ntawm txawv kiag li yam ntxwv, nyob rau hauv hais tias muaj yog tsis muaj ob tug zoo tib neeg (tshwj tsis yog zoo tib yam cov menyuam ntxaib), cov txawv nta ntawm tsos.

Tus qauv ntawm DNA muaj xws li tej qab zib?

Lub hauv paus ntawm tej organic teeb meem - ib tug carbon saw atoms. Cov DNA molecule tsis yog ib qho kev zam. Tom qab tag nrho cov DNA nkag mus rau qab zib, namely, nws muaj ib tug sib lawv liag ntawm tsib carbon atoms, ua ke nyob rau hauv ib tug cyclic qauv. Qhov no tib molecule yog tu ncua los ntawm ib tug oxygen choj nyob rau hauv lub zuag qhia tag nrho kev voj voog.

Cov tshuaj nyob tus yeees ntawm lub qab zib yog qhia los ntawm cov nram qab no empirical mis: C ₅ H ₁₀ O _4. Qhov no molecule - aldopentoza muaj tsib carbon atoms, cov mus rau hauv lub voj. Nyob rau hauv tas li ntawd, yog ib lub atoms nyob rau hauv cov saw hlau es tsis txhob ntawm lub hydroxyl pab pawg neeg tsuas muaj hydrogen, yog li ntawd muaj yog ib tug prefix xws li "deoxy" nyob rau hauv lub qab zib title, i.e., tsis muaj oxygen.

Cov tshuaj nyob tus yeees ntawm qab zib twb tshwm sim thiab kawm Fibusom Lieven, uas qhib rau tag nrho cov qauv thiab tshuaj xwm ntawm lub compound nyob rau hauv 1929.

Base nyob rau hauv lub molecule

Organic bases yog ib feem ntawm cov DNA nucleic acid yuav tsum tau muab faib mus rau hauv ob lub ntsiab pawg.

1. Purine - complex lug tsim los ntawm ob tug ntawm cov pa roj carbon voj voog - ib tug tsib-membered thiab rau-membered. Cov no muaj xws adenine thiab guanine, uas yog complementary mus rau ib tug pyrimidine puag muaj li ntawm deoxyribonucleic acid.
2. Pyrimidine - rau-membered carbon rings. Qhov no muaj xws li thymine thiab cytosine.

Yog li, nws zoo nkaus li hais tias ib feem ntawm cov DNA qab zib thiab ib lub hauv paus kev cob cog rua rau txhua lwm yam thiab kev cob cog rua ntawm mus nrog tus radical ntawm phosphoric acid. Tag nrho ua ke nws puv nucleotide. Cov kev qauv ntawm ob-tso tseg DNA molecule nucleotides khi ntawm lawv tus kheej raws li ib tug txoj cai ntawm complementarity: adenine puag sau raws nkaus Ii thymine, guanine thiab - cytosine.

Hom bonds ntawm tus hais

Lub ntsiab yam ntawm kev sib raug zoo ntawm tivthaiv DNA lug raws li nram no:

• hydrogen;
• ncov qaumteb qabteb covalent;
• intermolecular rog ntawm attraction;
• Vahan der Waals sis raug zoo.

Qhov no tso cai rau koj mus muab ob npaug rau-tso tseg qauv nyob rau hauv peb conformations:

• thawj - linear sequences ntawm nucleotides;
• theem nrab - txhua helically cov yarns thiab ob tom ntej no mus rau txhua lwm yam;
• tertiary - complex conformational globule xav lub helical molecule.

Yog li qhov tseeb hais tias ib feem ntawm cov DNA nkag mus rau hauv qab zib, puag, thiab acid residues yog lub hauv paus ntawm nws cov qauv thiab cov av rau qhov kev siv ntawm ib tug xov tooj ntawm cov kev sib tshuam thiab tsim cov tshuaj bonds.

DNA muaj nuj nqis rau tus kab mob no

Muaj ntau ntau heev ib qho tseem ceeb cov ntsiab lus:

1. Molecules xam tau tias yog acids uas yog muaj nyob rau hauv cov tshuaj muaj pes tsawg leeg ntawm lub chromosomes uas txiav txim tus kheej ntawm tag nrho cov uas muaj sia nyob.
2. DNA - lub hauv paus ntawm synthesis ntawm complex polypeptide chains lub luag hauj lwm rau coding thiab kis tau tus mob ntawm roj ntsha sijhawm.
3. Deoxyribonucleic acid - puag rau transcription, i.e. thawj RNA synthesis, protein tom qab.

Tej dab tshwm sim nyob rau hauv tag nrho cov kab mob. Qhov no pub rau cov qauv no hu ua universal chav tsev ntawm tag nrho cov nyob yam.

Replicating molecules

Qhov no txoj kev nruab nrab yog ib tug doubling ntawm cov DNA molecule, tshwm sim nthawv nrog lub expenditure ntawm lub zog nyob rau hauv uas muaj sia nyob. Lub ntsiab tivthaiv nyob rau hauv cov ntaub ntawv no - DNA polymerase, ib qho enzyme catalyzing thiab tswj tag nrho synthesis.

Replication point yog tias txhua tus ntawm cov strands ntawm lub molecule faib thiab tau ob npaug nws cov linear ib theem zuj zus. Cov uas ua cov txheej txheem ua ob tug tshiab DNA molecules txhua yam uas muaj ib zaug xwb polypeptide saw laus, thiab ib tug thib ob lig tshiab, ua lub tsev raws li lub hauv paus ntsiab lus ntawm complementarity.

Txheej txheem nqi - muab lub progeny ntawm kev tshuaj ntsuam genetic ntaub ntawv nyob rau hauv nws txoj kev paub.