Name: ラックオペロン (Lac Operon)
Uploaded: 2021-01-14T06:48:04.000Z
Duration: 3 min 26 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

This animation will only focus on two of the three proteins encoded by the lac operon,

Gene expression can be induced (or turned on)

when a specific inducer molecule appears in a cell.

a repressor molecule prevents gene expression

by binding to the upstream controlling region.

Lactose is the lac operon inducer molecule.

After first appearing in the cellular environment,

lactose passively enters the E. coli cell

This binding releases the repressor from the controlling region.

RNA polymerase can begin transcription of the operon.

Here we show two of the three lac operon genes

which breaks down lactose into two simple sugars.

permease functions to provide a direct route

for the lactose outside the cell to be imported into the cell.

This import occurs at a much greater rate

than the passive transfer we first observed.

Because translation continues inside the cell,

other permease proteins become embedded in the membrane.

This further increases the rate at which lactose enters the cell.

ß-galactosidase breaks the cellular lactose into the simple sugars glucose and galactose.

Once its concentration is greatly reduced,

the lactose bound to the repressor are released.

At this point, the repressor again binds to the controlling region and gene expression is halted.

For all inducible systems, like the lac operon,

it is the interaction of the repressor and inducer molecules that mediate gene expression.