Lactose operon ua haujlwm li cas?
Lactose operon ua haujlwm li cas?

Video: Lactose operon ua haujlwm li cas?

Video: Lactose operon ua haujlwm li cas?
Video: Lecture on overview of Gene expression (lac and trp operons) 2024, Kaum ib hlis
Anonim

Cov lac , los yog lactose , ua haujlwm muaj nyob rau hauv E. coli thiab lwm yam kab mob enteric. Qhov no ua haujlwm muaj gene coding rau cov proteins nyob rau hauv tus nqi thauj lactose mus rau cytosol thiab zom nws mus rau hauv qabzib. Cov piam thaj no tom qab ntawd siv los ua kom muaj zog.

Tsis tas li ntawd, lactose tig rau lub lac operon li cas?

Cov lac operon ua ntawm E. coli muaj cov gene koom nrog lactose metabolism. Nws yog qhia tsuas yog thaum lactose tam sim no thiab qabzib tsis muaj. Ob tug regulators tig tus ua haujlwm "on" thiab "off" nyob rau hauv teb rau lactose thiab qib qabzib: cov lac repressor thiab catabolite activator protein (CAP).

Tsis tas li ntawd, dab tsi tshwm sim rau lac operon thaum muaj cov piam thaj thiab lactose? Thaum ob leeg muaj cov piam thaj thiab lactose , cov noob rau lactose metabolism yog transcribed mus rau ib qho me me. Maximal transcription ntawm lub lac operon tshwm sim tsuas yog thaum qabzib yog tsis tuaj thiab lactose yog tam sim no . Qhov kev txiav txim ntawm cyclic AMP thiab catabolite activator protein tsim cov nyhuv no.

Kuj nug, yuav ua li cas yog tias qib lactose qis?

Yog tus qib ntawm inducer lactose yog qis ces tus neeg teb xov tooj yog rov thaiv los ntawm repressor kom cov txheej txheem genes repressed ib zaug dua; txhawm rau txhawm rau tsim cov enzymes.

Yuav ua li cas yog ib qho operon koom?

Prokaryotic structural genes ntawm cov haujlwm muaj feem xyuam feem ntau koom rau hauv cov neeg ua haujlwm , txhua yam tswj los ntawm kev sau los ntawm ib tus neeg txhawb nqa. Kev tswj hwm cheeb tsam ntawm ib ua haujlwm suav nrog tus neeg txhawb nqa nws tus kheej thiab thaj av ib puag ncig tus txhawb nqa uas cuam tshuam txog kev hloov pauv tuaj yeem cuam tshuam rau kev hloov pauv.

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