Answer:
A repressor is a regulatory protein that may bind DNA to inhibit transcription. An operator is a DNA sequence that binds a regulatory protein. A promoter is a DNA sequence that binds RNA polymerase and regulates transcription. A corepressor is a compound that interacts with another protein or compound to form an active repressor. An inducer is a compound that induces or activates transcription, such as lactose.
Explanation:
Repressor proteins bind to DNA and RNA to suppress target gene expression. A DNA repressor blocks transcription by inhibiting the attachment of RNA polymerase to the promoter sequence, while an RNA repressor bind to the mRNA to block translation of the protein. An operator is a DNA sequence required for the attachment of transcription factors. The genes that are transcribed by the binding of a transcription factor to an operator sequence are collectively referred to as an operon. Operons are generally found in prokaryotes but they also can be found in some eukaryotes including Caenorhabditis elegans and Drosophila melanogaster. An inducer is a molecule that activates gene transcription either by binding to repressors/corepressors (thereby inactivating their functions) or by binding activators. For example, the allolactose act as an inducer of the lac operon.
