Control of Gene Expression in Prokaryotes and Eukaryotes

Group of structural genes plus sequences that control transcription

Encodes the regulator protein or RNA, product has regulatory role. helps to control the transcription of the structural genes of the operon. NOT part of the operon

Genes whose products, RNA or Proteins, interact with other sequences and affect the transcription or translation of those sequences

DNA sequence that is not transcribed, sequence has regulatory role (serves as binding site) they affect the expression of sequences to which they are physically linked.

Gene that is not regulated and is continually expressed

Encode the proteins used in metabolism or biosynthesis--non regulatory

Single bacterial RNA molecule that encodes more than one polypeptide chain, uncommon in euks. MANY GENES/transcript that share a pathway and are all terminated by the same terminator sequence-EFFICIENT

Regulatory protein is a repressor (Regulatory element effects the expression of sequences to which they are physically linked)

Regulatory protein is an activator

Transcription is normally off and something must happen to induce transcription to turn it on.

Transcription is normally on and something must happen to repress transcription, to turn it off

In the absence of inducers, Transcription and translation of the regulator gene produce an active regulator protein (repressor) that readily binds to the operator and prevents transcription of the structural genes.
If an inducer is present, the inducer binds to the active regulator protein and alters the shape of this repressor (allosteric protein) which is then unable to bind to the operator, transcription will take place because RNA polymerase binds to the operator.

Operator site overlaps the promoter site and the biding of the regulator protein to the operator physically blocks the binding of the RNA polymerase to the promoter and prevents transcription

Small molecule that binds to the repressor and makes it capable of binding to the operator

Small molecule that binds to the repressor and turns transcription on by altering the shape of the active regulator protein(repressor) thereby making the regulator unable to bind to the operator so RNA polymerase binds, thus, inducer increases transcription