Video: DNA ob lub helix nrhiav tau li cas?
2024 Tus sau: Miles Stephen | [email protected]. Kawg hloov kho: 2023-12-15 23:36
Cov Discovery ntawm DNA cov Qauv. Tsim los ntawm Rosalind Franklin siv cov txheej txheem hu ua X-ray crystallography, nws tau nthuav tawm helical puab ntawm DNA molecule. Watson thiab Crick paub qhov ntawd DNA tau tsim los ntawm ob txoj hlua ntawm nucleotide khub uas encode cov ntaub ntawv caj ces rau txhua yam muaj sia.
Kuj nug, ob lub helix nrhiav tau li cas?
Nws feem ntau ntseeg tias James Watson thiab Francis Crick nrhiav pom ob lub helix zoo li DNA. Tab sis qhov tseeb, lawv ua raws lawv txoj haujlwm ntawm ib tus ntawm lawv cov npoj yaig ntawm King's College hauv London - Rosalind Franklin, tus kws tshaj lij x-ray diffraction uas nws cov duab ntawm DNA proteins thaum ntxov xyoo 1950 tau nthuav tawm cov duab helix.
Tsis tas li ntawd, leej twg xub pom DNA? Ntau tus neeg ntseeg tias American biologist James Watson thiab English physicist Francis Crick nrhiav pom DNA hauv xyoo 1950. Qhov tseeb, qhov no tsis yog li ntawd. Hloov chaw, DNA tau pom thawj zaug hauv 1860s lig los ntawm Swiss chemist Friedrich Miescher.
Hauv qhov no, thaum twg DNA ob lub helix nrhiav tau?
1953, Leej twg nrhiav tau ob helical qauv ntawm DNA thiab thaum twg?
Francis Crick
Pom zoo:
Ua li cas koj thiaj nrhiav tau lub ntiajteb txawj nqus ntawm cov kua sib tov?
Tam sim no faib tag nrho qhov ceev los ntawm qhov ceev ntawm cov dej thiab koj tau txais SG ntawm qhov sib tov. Dab tsi yog cov kua uas muaj qhov ceev tshaj plaws? Thaum sib npaug ntawm ob yam khoom sib xyaw, qhov tshwj xeeb ntawm qhov sib tov yog 4. Ib qho loj ntawm cov kua ntawm qhov ntom ntom p yog tov nrog qhov sib npaug ntawm lwm cov kua ntawm qhov ntom ntom 3p
Yuav ua li cas koj nrhiav tau lub subSet ntawm ib lub teeb?
Number of Subsets ntawm ib tug muab Set: Yog hais tias ib tug set muaj 'n' ntsiab, ces tus naj npawb ntawm subsets ntawm lub teeb yog 22. Yog hais tias ib tug set muaj 'n' ntsiab, ces tus naj npawb ntawm subsets tsim nyog ntawm lub teeb yog 2n - 1 ⇒ Tus naj npawb ntawm cov subsets ntawm A yog 3 = 22 - 1 = 4 - 1
Yuav ua li cas koj thiaj nrhiav tau tus nqi ntawm tus qauv txhais tau tias?
Qhov xav tau tus nqi ntawm tus qauv txhais tau tias yog cov pej xeem txhais tau tias, thiab SE ntawm tus qauv txhais tau tias yog SD ntawm cov pej xeem, muab faib los ntawm lub hauv paus square ntawm tus qauv loj
Henri Becquerel nrhiav tau dab tsi uas ua rau nws tau txais 1903 Nobel nqi zog Nws nrhiav tau dab tsi txog lub caij uranium?
Teb: Henri Becquerel tau txais ib nrab ntawm qhov khoom plig rau nws qhov kev tshawb pom ntawm cov hluav taws xob tsis zoo. Teb: Marie Curie tau kawm txog cov hluav taws xob ntawm tag nrho cov tebchaw uas muaj cov xov tooj cua paub, suav nrog uranium thiab thorium, uas nws tom qab pom kuj tseem muaj xov tooj cua
Yuav ua li cas koj nrhiav tau lub coordinates ntawm lub midpoint ntawm lub laij lej?
Yuav ua li cas thiaj nrhiav tau ib qho chaw nruab nrab Sau cov kev tswj hwm (x1,y1) thiab (x2,y2). Muab cov nqi rau hauv cov qauv. Ntxiv qhov tseem ceeb hauv kab lus thiab faib txhua qhov tshwm sim los ntawm 2. Cov txiaj ntsig tshiab tsim cov kev tswj hwm tshiab ntawm qhov nruab nrab. Tshawb xyuas koj cov txiaj ntsig siv lub laij lej nruab nrab