Video: Meselson thiab Stahl nrhiav tau dab tsi?
2024 Tus sau: Miles Stephen | [email protected]. Kawg hloov kho: 2023-12-15 23:36
Cov Meselson thiab Stahl Kev sim piav qhia
Meselson thiab Stahl kuaj lub hypothesis ntawm DNA replication. Lawv coj cov kab mob hauv 15N nruab nrab. Qhov tshwm sim no yog raws nraim li tus qauv semiconservative kwv yees: ib nrab yuav tsum yog 15N-14N nruab nrab ntom ntom DNA thiab ib nrab yuav tsum yog 14N-14N lub teeb ntom ntom DNA
Hauv qhov no, qhov kev sim Meselson Stahl tau qhia dab tsi?
Cov kev sim ua los ntawm Meselson thiab Stahl pom tau hais tias DNA replicated semi-conservatively, txhais tau hais tias txhua strand nyob rau hauv ib tug DNA molecule ua hauj lwm raws li ib tug qauv rau synthesis ntawm ib tug tshiab, complementary strand. Txawm tias Meselson thiab Stahl ua lawv kev sim hauv cov kab mob E.
Tom qab ntawd, lo lus nug yog, Meselson thiab Stahl ua li cas qhov txawv ntawm cov qub thiab tshiab tsim DNA? Cov txoj kev Meselson thiab Stahl tsim tau tso cai rau lawv paub qhov txawv uas twb muaj lawm DNA los ntawm tshiab synthesized DNA thiab taug qab tshiab thiab qub DNA dhau ntau lub voj voog ntawm rov ua dua. Cov 15N thiab 14N daim ntawv lo DNA yog ces taug qab siv kev kub ceev centrifugation thiab ceev * gradient tsim nrog cesium chloride (CsCl).
Tsuas yog li ntawd, Meselson thiab Stahl tau koom nrog DNA li cas?
Meselson thiab Stahl incorporated non-radioactive isotopes ntawm nitrogen nrog hnyav sib txawv rau hauv DNA ntawm E. coli. Raws li DNA muaj nitrogen ntau, tsuav yog cov kab mob loj hlob hauv nruab nrab uas muaj nitrogen ntawm ib qho isotope, cov kab mob yuav siv cov nitrogen no los tsim. DNA.
Tus qauv ntawm kev rov ua dua tshiab twg tau ua tiav qhov txiaj ntsig ntawm Meselson Stahl kev sim txhawb nqa?
Cov Cov txiaj ntsig ntawm Meselson - Stahl kev sim tau txhawb nqa ib tug semiconservative qauv ntawm DNA rov ua dua . Thawj rov ua dua nyob rau hauv 14 N nruab nrab tsim ib pawg ntawm hybrid (14N thiab 15N) DNA. Qhov no tshwm sim tshem tawm cov conservative qauv ntawm replication.
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