Components of lac operon
Inducer-repressor complex
A molecular complex consisting of repressor protein and a bound inducer molecule
Operon
A set of adjacent genes that are transcribed in a polycistronic mRNA and thus are coordinately regulated
Activator protein
A transcription factor that binds to regulatory sequences associated with a gene
Inducer
Accessory molecule that binds to a protein that leads to the activation of gene expression; can bind to a repressor protein and prevent its function or to an activator protein and stimulate its function
Lac operon
An inducible operon system under both negative and positive control
Polycistronic
Describes a type of mRNA that can encode for more than one polypeptide separately within the same RNA molecule
Attenuation
Fine tuning of the rate of transcription in response to the needs of the cell
CAP-cAMP complex
Formed by joining CAP to cAMP; the complex binds to the CAP binding site of the bacterial lac promoter to regulate gene expression
Transcription factor
Protein that binds promoters and is functional in transcription
Promoter
Regulatory DNA sequence near 5' end of a gene that acts as the binding site for RNA polymerase and directs RNA polymerase to the start of transcription
Operator
Regulatory DNA sequence that a repressor or activator binds to
Anabolic pathway
Synthesizes a needed compound
RNA polymerase
The enzyme that catalyzes the synthesis of RNA
Repressor protein
Transcription factor that binds to regulatory sequences associated with a gene and represses that gene's expression
CAP binding site
Where positive control of lac operon occurs