Lac operon

Concept

Lac operon

Set of bacterial genes activated to metabolize lactose when glucose is unavailable.

It is an operon, that is, a group of bacterial genes transcribed together under a single promoter, that encodes the proteins needed to import and break down lactose.

It is the classic model of gene regulation in prokaryotes: it illustrates how a bacterium switches genes on or off depending on the availability of nutrients in its environment, avoiding wasting resources on unnecessary enzymes.

The video explains that Escherichia coli releases repression of the lac operon when lactose is the only available carbon source, allowing it to produce β-galactosidase, but that it remains inactive when the medium contains glucose.

Relations

• Escherichia coli → regulates → Lac operon
  Evidence

  Sources · original ES transcript

  • The Rule Behind All Life | The Central Dogma11:56

    Escherichia coli, el organismo modelo por excelencia, es capaz de ajustar su maquinaria genética según el tipo de nutriente disponible en su entorno.

• Lactose → induces → Lac operon
  Evidence

  Sources · original ES transcript

  • The Rule Behind All Life | The Central Dogma12:06

    Cuando la única fuente de carbono es lactosa, la bacteria libera la represión del operón lac,

• Glucose → keeps inactive → Lac operon
  Evidence

  Sources · original ES transcript

  • The Rule Behind All Life | The Central Dogma12:24

    Pero si el medio contiene glucosa, la situación cambia por completo: el operón lac permanece inactivo.

• Lac operon → enables production of → β-galactosidase
  Evidence

  Sources · original ES transcript

  • The Rule Behind All Life | The Central Dogma12:13

    lo que permite la transcripción de genes clave y la producción de β-galactosidasa, una enzima especializada en descomponer la lactosa

Sources · original ES transcript

• The Rule Behind All Life | The Central Dogma12:06

  Cuando la única fuente de carbono es lactosa, la bacteria libera la represión del operón lac,

• The Rule Behind All Life | The Central Dogma12:24

  Pero si el medio contiene glucosa, la situación cambia por completo: el operón lac permanece inactivo.