Tus qauv ntawm DNA muaj ... tshuaj nyob tus yeees ntawm DNA

Muaj coob tus neeg tau yeej ib txwm xav yog vim li cas tej yam tshwm sim muaj rau cov niam txiv muab tus me nyuam (piv txwv li, lub qhov muag xim, plaub hau, lub ntsej muag zoo, thiab lwm tus). Science tau qhov tseeb hais tias cov hloov mus rau cov yam ntxwv nyob rau hauv lub caj khoom, los yog DNA.

Yuav ua li cas yog DNA?

Tam sim no, nyob rau hauv lub deoxyribonucleic acid to taub txoj compound uas yog lub luag hauj lwm rau cov kis ntawm cov roj ntsha yam ntxwv. Qhov no molecule nyob rau hauv txhua txhua cell ntawm peb lub cev. Nws programmed lub ntsiab nta ntawm peb lub cev (rau txoj kev loj hlob ntawm ib tug kev zoo losis phem raws li ib tug protein).

Ua li cas nws muaj? Tus qauv ntawm DNA muaj txoj tebchaw - nucleotides. By thaiv yog meant nucleotide los yog mini compound muaj nyob rau hauv nws cov qauv lub nitrogenous puag, lub qhov seem ntawm phosphoric acid thiab ib tug qab zib (nyob rau hauv cov ntaub ntawv no - deoxyribose).

DNA yog ib tug muab ob npaug rau tso tseg molecule, nyob rau txhua lub circuits kev cob cog rua rau lwm los ntawm cov nitrogen bases ntawm lub hauv paus ntsiab lus ntawm complementarity.

Tsis tas li ntawd, nws yuav lam xav tias nyob rau hauv lub DNA muaj xws li cov noob - kev nucleotide sequences lub luag hauj lwm rau cov protein ntau synthesis. Yuav ua li cas yog cov tshuaj thaj chaw ntawm cov qauv ntawm cov deoxyribonucleic acid yog?

nucleotide

Raws li hais, qhov yooj yim ntxwv tsev ntawm deoxyribonucleic acid yog ib tug nucleotide. Qhov no yog ib tug complex chaw. Muaj pes tsawg leeg cov nram qab no DNA nucleotide.

Nyob rau hauv lub center yog tsib-tivthaiv nucleotide qab zib (deoxyribose nyob rau hauv DNA yog nyob rau hauv sib piv rau RNA, uas muaj ribose). Yuav kom nws yog tuaj koom lub nitrogenous puag, uas yog cais 5 hom: adenine, guanine, thymine, uracil thiab cytosine. Tsis tas li ntawd, txhua nucleotide yog muaj li ntawm thiab cov residue phosphoric acid.

Tus qauv ntawm DNA muaj tsuas yog cov nucleotides uas muaj cov qhia cov yam ntxwv tsev.

Tag nrho cov nucleotides cov txheej txheem ntawm nyob rau hauv ib cov saw thiab ua raws li txhua lwm yam. Grouping ntawm triplets (peb nucleotides), lawv tsim ib tug ib theem zuj zus nyob rau hauv uas txhua triplet coj mus rau ib tug kev amino acid. Cov no ib tug saw.

Lawv tuaj koom ua ke los ntawm kev sib txuas ntawm nitrogen bases. Cov yooj yim kev sib raug zoo ntawm nucleotides thaum uas tig mus circuits - hydrogen.

Nucleotide sequences yog lub hauv paus ntawm noob. Kev ua txhaum nyob rau hauv lawv cov qauv, ua rau tsis ua hauj lwm nyob rau hauv lub synthesis ntawm cov nqaijrog thiab manifestation ntawm change. Tus qauv ntawm DNA muaj tib lub noob uas txiav txim zoo tag nrho cov neeg thiab paub qhov txawv lawv los ntawm lwm yam kab mob.

kev hloov kho ntawm ib tug nucleotide

Nyob rau hauv tej rooj plaub, rau ib tug ruaj khov kev hloov ntawm ib tug kev zoo losis phem kev hloov kho ntawm nitrogenous puag yog siv. Cov tshuaj nyob tus yeees ntawm cov DNA yog hloov los ntawm Symptoms ntawm ib tug methyl pab pawg neeg (CH3). Tej kev hloov kho (ib nucleotide) tso cai rau mus rau stabilize noob qhia thiab hloov mus rau lwm cov yam ntxwv tus ntxhais lub hlwb.

Qhov no "txoj kev txhim kho" ntawm lub molecular qauv tsis cuam tshuam rau lub koom haum ntawm nitrogenous bases.

Qhov no kev hloov kho yog siv nrog X-chromosome inactivation. Raws li ib tug tshwm sim, tsim Barr lub cev.

Nyob rau hauv cov ntaub ntawv uas muaj zog carcinogenesis DNA tsom qhia tau hais tias lub saw ntawm nucleotides twb raug mus rau methylation nyob rau ntau substrates. Nyob rau hauv observational kev tshawb fawb, nws twb pom hais tias lub hauv paus ntawm lub hloov no feem ntau yog ib tug methylated cytosine. Feem ntau thaum lub sij hawm mob demethylation txheej txheem yuav txhawb lub tsheb, tab sis vim nws tsis yooj, tshuaj tiv thaiv no yog tsis nqa tawm.

DNA qauv

Nyob rau hauv cov qauv ntawm cov molecule yog ob hom lug. Tus thawj hom - ib tug linear ib theem zuj zus ntawm nucleotides tsim. Lawv siv yog kev kawm mus rau tej yam kev cai. Ntaubntawv povthawj siv rau ntawm lub nucleotide DNA molecule pib nrog lub 5'-terminus thiab 3'-terminus xaus. Qhov thib ob Circuit Court nyob rau hauv tsis tooj, yuav ua lub tsev nyob rau hauv tib yam, tsuas yog nyob rau hauv molecules yog spatially opposite ib leeg, nyob rau lub 5'-terminus ntawm ib saw yog nyob yam txawv tus 3'-end ntawm lub thib ob.

helix - DNA theem nrab qauv. Tshwm sim los ntawm lub xub ntiag ntawm hydrogen bonds xws li ntawm tawm tsam nucleotides. Lub hydrogen daim ntawv cog lus yog tsim (tsuas thymine, guanine thiab sib piv yuav ua tau rau Piv txwv li, yam txawv lub thawj strand adenine - uracil los yog cytosine) ntawm complementary nitrogenous bases. Tej cov neeg yog vim lub fact tias cov kev tsim kho ntawm lub thib ob Circuit Court yuav siv sij hawm qhov chaw nyob rau hauv lub hauv paus ntawm cov thawj, yog li ntawm cov nitrogenous bases muaj lub caij nyoog match.

Lub synthesis ntawm cov molecule

Yuav ua li cas yog tus DNA molecule tsim?

Nyob rau hauv lub voj voog ntawm nws tsim yog peb theem:

• Disconnection circuits.
• Accession synthesizing units rau ib qho ntawm lub chains.
• Extension ntawm tus thib ob Circuit Court raws li lub hauv paus ntsiab lus ntawm complementarity.

Nyob rau theem ntawm kev sib cais ntawm molecules yog yeej los ntawm enzymes - DNA gyrase. Cov enzymes muaj teem nyob rau kev puas tsuaj ntawm hydrogen bonds ntawm lub chains.

Tom qab divergence chains los nyob rau hauv yooj yim synthesizing enzyme - DNA polymerase. Nws ua raws li yog pom nyob rau ib qhov chaw 5 '. Tom ntej no, lub enzyme yog tsiv mus rau lub 3'-end, ib txhij attaching lub yuav tsum tau nucleotides nrog tsim nyog nitrogenous bases. Tom qab ncav qhov predetermined ntau (Terminator) nyob rau hauv lub 3 'kawg, polymerase chain yog kaw los ntawm lub hauv paus.

Thaum tsim subsidiary Circuit Court ntawm lub bases tsim hydrogen bonds, thiab cov uas tuav lub tshiab khiv tsim DNA molecule.

Kuv yuav nrhiav tau qhov no molecule?

Yog hais tias koj delve rau hauv tus qauv ntawm lub hlwb thiab ntaub so ntswg, nws yuav pom tias cov DNA yog tsuas yog nyob rau hauv lub cell nucleus. Cov ntsiav yog lub luag hauj lwm rau cov tsim ntawm tshiab subsidiaries, hlwb los yog lawv clones. Yog li kev tshuaj ntsuam genetic ntaub ntawv pov nyob rau ntawd, yog muab faib nruab nrab ntawm tus tshiab khiv tsim hlwb uniformly (generated clones) los yog cov (feem ntau muaj cai xws li ib tug tshwm sim thaum lub sij hawm meiosis). Lub yeej ntawm cov tub ntxhais tau nyob rau hauv ib tug ua txhaum ntawm lub tsim ntawm tshiab cov ntaub so ntswg, uas ua rau yus change.

Nyob rau hauv tas li ntawd, ib tug tshwj xeeb ntawm roj ntsha khoom muaj nyob rau hauv lub mitochondria. Lawv DNA sib txawv dog dig los ntawm hais tias nyob rau hauv lub nucleus (mitochondrial deoxyribonucleic acid muaj ib tug annular zoo thiab ua ob peb lwm zog).

Molecule nws tus kheej muaj peev xwm yuav cais los ntawm tej cell ntawm lub cev (rau txoj kev tshawb no ntawm feem ntau siv kua ntswg los ntawm lub sab hauv ntawm lub sab plhu los yog cov ntshav). Tsis genetic khoom xwb nyob rau hauv lub epithelium exfoliates thiab tej ntshav (erythrocytes).

zog

Muaj pes tsawg leeg ntawm lub DNA molecule txiav txim qhov kev kawm ntawm nws cov ntaub ntawv kis tau tus mob muaj nuj nqi los ntawm tiam mus rau tiam. Qhov no yog vim lub synthesis ntawm tej yam proteins uas ua rau lub manifestation ntawm ib tug genotype (internal) los yog phenotypic (lwm - piv txwv li, cov xim ntawm lub qhov muag los yog cov plaub hau) feature.

Cov kis tau tus mob ntawm cov ntaub ntawv yog nqa tawm los ntawm qhov kev siv ntawm nws caj code. Nyob rau lub hauv paus ntawm cov ntaub ntawv encrypted nyob rau hauv lub caj code, muaj ib tug kev loj hlob ntawm tej lus, ribosomal thiab hloov RNA. Txhua tus ntawm lawv yog lub luag hauj lwm rau ib lub txiav txim - tub txib RNA yog siv coj los ua ke cov nqaijrog muab kev koom tes nyob rau hauv ribosomal protein molecules los ua ke, thiab ntaub ntawv ib tug coj thauj proteins.

Tej tsis ua hauj lwm nyob rau hauv lawv lub lag luam los yog cov qauv kev hloov ua rau muaj kev cuam tshuam ntawm cov nuj nqi ua, thiab cov tsos ntawm atypical nta (change).

DNA leej txiv xeem los mus txiav txim hauv lub xub ntiag yam tsos mob ntawm cov neeg.

kev tshuaj ntsuam genetic kev ntsuam xyuas

Yuav ua li cas tam sim no yuav siv tau los ntawm cov kev kawm txog cov kev tshuaj ntsuam genetic khoom?

DNA tsom xam yog siv los mus txiav txim ib tug xov tooj ntawm lwm yam los yog hloov nyob rau hauv tus kab mob.

Tus thawj txoj kev tshawb no los mus txiav txim hauv lub xub ntiag ntawm congenital, pub kab mob. Tej cov kab mob xws li Down syndrome, tsi txawj has lug, Marfan syndrome.

Yuav kom txiav txim kinship DNA kuj yuav kawm. Leej Txiv xeem tau ntev lawm coob leej ntau tus nyob rau hauv ntau, feem ntau raws li txoj cai, cov txheej txheem. Txoj kev tshawb no yog tshuaj rau kev txiav txim lub caj kev sib raug zoo ntawm tsaub me nyuam. Feem ntau qhov no kuaj neeg thov kev pab dhau rau lub qub txeeg qub teg nyob rau hauv cov kev tshwm sim ntawm teeb meem nrog cov tub ceev xwm.