Biochemistry Notes > Queen Mary, University Of London Biochemistry Notes > Genes and Bioinformatics Notes

The Lac Operon Notes

This is a sample of our (approximately) 3 page long The Lac Operon notes, which we sell as part of the Genes and Bioinformatics Notes collection, a First (78%) package written at Queen Mary, University Of London in 2013 that contains (approximately) 37 pages of notes across 19 different documents.

Learn more about our Genes and Bioinformatics Notes

The Lac Operon Revision

The following is a plain text extract of the PDF sample above, taken from our Genes and Bioinformatics Notes. This text version has had its formatting removed so pay attention to its contents alone rather than its presentation. The version you download will have its original formatting intact and so will be much prettier to look at.

Operons: Bacterial genes coding for proteins whose functions are related may be organised in a cluster that is transcribed into a polycistronic mRNA from a single promoter. Control of this promoter regulates all the genes. Unit of regulation (contains structural genes and cis-acting elements) called the operon.

The Lac Operon: Lactose pathway in E. coli enables bacteria to take up and metabolise β-galactoside sugars (e.g. lactose). 3 lac structural genes:

• lacZ encodes the enzyme β-galactosidase (breaks down β-galactosides).

• lacY encodes permease (transports β-galactosides into cell).

• lacA encodes transacetylase (transfers acetyl groups). 3 genes regulated by single promoter and operator, which overlap. LacI is upstream and codes for lac operon repressor. It is on a separate gene and has its own promoter. Lac operon has 3 operators. Tetramer can bind 2 operators. Full repression requires binding to primary operator (lacO1) and one additional (lacO2/O3).

****************************End Of Sample*****************************

Buy the full version of these notes or essay plans and more in our Genes and Bioinformatics Notes.