Activa JavaScript para disfrutar de los vídeos de la Mediateca.
Operon Lac
Ajuste de pantallaEl ajuste de pantalla se aprecia al ver el vídeo en pantalla completa. Elige la presentación que más te guste:
Regulacion expresion procariotas
The E. coli lac operon is an example of an inducible set of genes.
00:00:09
These genes are responsible for the breakdown of lactose into sugars used for cellular metabolism.
00:00:24
This inducible system also involves bacterial DNA, a repressor, mRNA, and the sugar molecule lactose.
00:00:30
This animation will only focus on two of the three proteins encoded by the lac operon,
00:00:47
beta-galactosidase and permease.
00:00:54
Gene expression can be induced or turned on when a specific inducer molecule appears in a cell.
00:01:00
For inducible systems, a repressor molecule prevents gene expression
00:01:14
by binding to the upstream controlling region.
00:01:18
Lactose is the lac operon inducer molecule.
00:01:23
After first appearing in the cellular environment,
00:01:26
Lactose passively enters the E. coli cell and binds to the repressor molecule.
00:01:29
This binding releases the repressor from the controlling region.
00:01:34
At this point, RNA polymerase can begin transcription of the operon.
00:01:38
Here we show two of the three lac operon genes being transcribed into mRNA.
00:01:43
Ribosomes then bind to the mRNA and the two proteins are translated.
00:01:49
The first protein is beta-galactosidase, which breaks down lactose into two simple sugars.
00:01:57
The second protein is permease, a membrane-bound protein.
00:02:04
When embedded in the cell membrane, permease functions to provide a direct route for the lactose outside the cell to be imported into the cell.
00:02:08
This import occurs at a much greater rate than the passive transfer we first observed.
00:02:16
Because translation continues inside the cell, other permease proteins become embedded in the membrane.
00:02:21
This further increases the rate at which lactose enters the cell.
00:02:28
Beta-galactosidase breaks the cellular lactose into the simple sugars glucose and galactose.
00:02:32
Once its concentration is greatly reduced, the lactose bound to the repressor are released.
00:02:38
At this point, the repressor again binds to the controlling region and gene expression is halted.
00:02:44
For all inducible systems like the lac operon,
00:02:53
it is the interaction of the repressor and inducer molecules that mediate gene expression.
00:02:56
Thank you.
00:03:01
- Valoración:
- Eres el primero. Inicia sesión para valorar el vídeo.
- 1
- 2
- 3
- 4
- 5
- Idioma/s:
- Autor/es:
- Virtual Cell
- Subido por:
- Benito H.
- Licencia:
- Reconocimiento - No comercial - Compartir igual
- Visualizaciones:
- 951
- Fecha:
- 10 de septiembre de 2010 - 9:22
- Visibilidad:
- Público
- Enlace Relacionado:
- Benito Hernández Giménez
- Centro:
- IES MORATALAZ
- Descripción ampliada:
- El operón lac es un operón requerido para el transporte y metabolismo de la lactosa en la bacteria Escherichia coli, así como en algunas otras bacterias entéricas. Presenta tres genes estructurales adyacentes, un promotor, un terminador y un operador.El operón lacglucosa y de lactosa. La regulación génica del operón lac fue el primer mecanismo regulatorio de la expresión genética en ser elucidado, y es utilizado a menudo como un ejemplo clásico de la regulación génica en procariotas. es regulado por varios factores, incluyendo la disponibilidad de
- Duración:
- 03′ 24″
- Relación de aspecto:
- 1.31:1
- Resolución:
- 1024x780 píxeles
- Tamaño:
- 20.54 MBytes