1. OPERON: An OPERON is a stretch of DNA consisting of an operator, a promoter and genes for a related set of proteins usually making up an entire metabolic pathway.
2. 2. GENES OF AN OPERON: The GENES OF AN OPERON are arranged sequentially after the promoter.
3. PROMOTER: A PROMOTER is a specific nucleotide sequence in DNA that binds RNA polymerase, positioning it to start transcribing RNA at the appropriate place.
4. REGULATORY GENE: A REGULATORY GENE codes for a protein, such as a repressor that controls the transcription of another gene or group of genes.
5. OPERATOR: Regulatory protein binds to the OPERATOR to control the expression of the operon.
6. REPRESSOR: A REPRESSOR is a protein that inhibits gene transcription. In prokaryotes, this protein binds to the DNA in or near the promoter.
7. INDUCER: AN INDUCER is a specific small molecule that binds to a bacterial regulatory protein and changes its shape so that it cannot bind to an operator, thus switching an operon on.
An operon refers to a unit of DNA which is made up of connected genes that regulate a particular protein synthesis. Operons are found in prokaryotes, eukaryotes and viruses. Operon allows the protein synthesis in these organisms to be controlled coordinately in response to the needs of the cell. Proteins are produced only when they are needed, thus the operon helps the cell to conserve energy. An example of a well studied operon is the Lac operon of E. coli.
