The lac operon - Below Allolactose an isomer of lactose...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
The lac operon Lactose is a sugar found in milk. If lactose is present, E. coli (the common intestinal bacterium) needs to produce the necessary enzymes to digest it. Three different enzymes are needed. In the diagrams below, genes A, B, and C represent the genes whose products are necessary to digest lactose. In the normal condition, the genes do not function because a repressor protein is active and bound to the DNA preventing transcription. When the repressor protein is bound to the DNA, RNA polymerase cannot bind to the DNA. The protein must be removed before the genes can be transcribed.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Below: Allolactose, an isomer of lactose, binds with the repressor protein inactivating it. The repressor protein is produced by a regulator gene . The region of DNA where the repressor protein binds is the operator site. The promoter site is a region of DNA where RNA polymerase can bind. The entire unit (promoter, operator, and genes) is an operon . The operator acts like a switch that can turn several genes on or off at the same time. The lac operon is an example of an inducible operon because the structural genes are normally inactive. They are activated when lactose is present....
View Full Document

This note was uploaded on 01/04/2012 for the course BSC BSC1005 taught by Professor Orlando,rebecca during the Fall '10 term at Broward College.

Page1 / 2

The lac operon - Below Allolactose an isomer of lactose...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online