the lac operator site within the lac operon is an example of a prokaryotic gene regulation.
the lac operator site within the lac operon is an example of a prokaryotic gene regulation.
the lac operator site within the lac operon is an example of a?
prokaryotic gene regulation
the "lac" operon (lactose operon) is an operon required for the transport and metabolism of lactose in "escherichia coli" and many other enteric bacteria. although glucose is the preferred carbon source for most bacteria, the "lac" operon allows for the effective digestion of lactose when glucose is not available through the activity of beta-galactosidase. gene regulation of the "lac" operon was the first genetic regulatory mechanism to be understood clearly, so it has become a foremost example of prokaryotic gene regulation. it is often discussed in introductory molecular and cellular biology classes for this reason. this lactose metabolism system was used by françois jacob and jacques monod to determine how a biological cell knows which enzyme to synthesize. their work on the lac operon won them the nobel prize in physiology in 1965.
lac operon
discovered in 1953 by jacques monod and colleagues, the trp operon in "e. coli" was the first repressible operon to be discovered. while the lac operon can be activated by a chemical (allolactose), the tryptophan (trp) operon is inhibited by a chemical (tryptophan). this operon contains five structural genes: trp e, trp d, trp c, trp b, and trp a, which encodes tryptophan synthetase. it also contains a promoter which binds to rna polymerase and an operator which blocks transcription when bound to the protein synthesized by the repressor gene (trp r) that binds to the operator. in the lac operon, lactose binds to the repressor protein and prevents it from repressing gene transcription, while in the trp operon, tryptophan binds to the repressor protein and enables it to repress gene transcription. also unlike the lac operon, the trp operon contains a leader peptide and an attenuator sequence which allows for graded regulation. this is an example of the corepressible model.
operon