Lub zog ntawm DNA thiab nws cov qauv

Hauv plawv ntawm lub nyob hlwb ntawm tus kab mob no tseem ceeb heev functions yog zog lom polymers, nucleic acids, carbohydrates, cov nqaijrog thiab lipids. Biopolymers muaj monomers, hydrocarbon lug, uas kuj muaj xws li nitrogen, oxygen, sulfur thiab phosphorus.

Nyob rau hauv lub xyoo pua puv 19, txoj kev tshawb ntawm cov qauv ntawm cov tshuaj yog chiv uas roos ib tug nyob ntawm tes, tab sis cov kev ua ntawm DNA, cov nqaijrog, RNA, thiab lawv cov qauv raug thaum kawg txiav txim siab nyob rau hauv lub xyoo pua 20th.

Friedrich Miescher nyob rau hauv 1868, raug rho tawm los ntawm cell nuclei phosphorous leukocytes thiab hu ua nws nukleina. Ces Richard Altman nyob rau hauv 1889 txiav txim tias qhov no tshuaj muaj tshwj xeeb acids thiab protein. Ces rau thawj lub sij hawm thiab hnov txog lub sij hawm "nucleic acid". Txawm li cas los, rau tsim kom muaj lub muaj nuj nqi ntawm nucleic acids tseem nyob deb tawm.

DNA - deoxyribonucleic acid - yog qhov loj tshaj plaws lom polymers muaj li ntawm pua pua monomers - deoxyribonucleotides. Nyob rau hauv lawv muaj pes tsawg leeg tsuas yog qab zib (deoxyribose), muaj xws li 4 hom nucleotides: adenine - A, thymidine - T, cytosine - C, guanine - G.

Tus thawj lub sij hawm twb xam tau tias yog ib tug DNA nucleic acid ntawm cov tsiaj keeb kwm, vim nws twb cais los ntawm cov thymus ntawm cov tsiaj, thiab RNA tau cais los ntawm nplej kab - zaub. Nws twb ntseeg tau tias thaum kawg lub biochemical txawv ntawm haiv neeg hlwb twb pom teny thiab cov tsiaj. Txawm li cas los, nyob rau hauv nruab nrab ntawm lub thib nees nkaum xyoo pua lawv pom tias RNA thiab DNA yog muaj nyob rau hauv tag nrho cov hlwb.

Tam sim ntawd cov qauv pib kawm nucleic acids Erwin Chargaff, uas nyob rau hauv 1953 pom tias nucleotides uas yog ib feem ntawm lub tib lub npe acid daim ntawv officers nrog nruj regularity.

Cov kev twb kev txuas ib txwm coj ib tug pyrimidine thiab purine paus ntawm ib tug, T = C, A = T. ntawd yog, adenine uake rau thymidine thiab guanine - nrog cytosine.

Thiab rau DNA muaj nuj nqi ib qho tseem ceeb tias cov kev twb kev txuas nyob rau hauv thawj cov ntaub ntawv muab hydrogen 2 officers, thiab lub thib ob - peb.

Chargaff cov kev cai muaj pov thawj los luj rau ntawm uas Watson thiab Crick ua qauv ntawm cov DNA ob helix.

Nyob rau hauv no molecule, raws li zoo raws li nyob rau hauv protein molecules, txawv rau cov thawj, nrab thiab tertiary lug.

Lub hom qauv - ib tug linear ib theem zuj zus ntawm monomers nyob rau hauv tib lub saw.

Ntawm cov hoob kawm, nyob rau hauv qhov xwm ntawm tus DNA nyob rau hauv ib cov saw tsis tshwm sim, tiam sis ntawm no peb yuav sib tham txog cov thawj cov qauv ntawm biopolymers, uas txhais tau tias tag nrho cov ntawm nws lub zog.

Secondary qauv - ib tug spatial cov yam ntxwv ntawm cov biopolymer. Nyob rau hauv cov ntaub ntawv ntawm DNA nws yog ib tug polynucleotide ob chains, txhua tus uas yog cov nyob rau hauv ib txoj cai helix, thiab ob yog ib txhij cov nyob rau hauv ib tug clockwise kev taw qhia txog cov kev axis. Cov chains yog muaj nyob rau tom ntej no mus rau lub rog ntawm hydrogen tsevneeg. Lub tertiary qauv ntawm cov DNA helix molecules ntxiv txhais.

Ib tug giant kauj ruam rau pem hauv ntej twb tau nrog cov foundations uas cov kev ua ntawm DNA yog hloov thiab cia ntawm kev tshuaj ntsuam genetic ntaub ntawv. DNA muaj cov caj ces kev pab cuam ntawm cov qauv ntawm cov nqaijrog, hais rau txhua kab. Lawv, nrog rau cov RNA molecules qhia lub caj ces ntaub ntawv los ntawm kab mob mus kab. Cov DNA yog tseem lub luag hauj lwm rau qhov kev siv thiab kev tshuaj ntsuam genetic ntaub ntawv. Lawv muab kev koom tes nyob rau hauv transcription dab, replication thiab txhais lus, yog li kom ntseeg tau lub synthesis ntawm ntau yam proteins.