Concept explainers
Compare and contrast the roles of a corepressor and an inducer in negative regulation of an operon.
To compare: The functions of a corepressor and an inducer in negative regulation of an operon.
Introduction: Gene regulation is the process through which the cells control the expression of genes. It controls genes that are expressed to form a specific functional protein depending on the cell type. There are mechanisms that control gene expression at different levels.
Explanation of Solution
Operon contains coding DNA sequences, regulatory DNA sequences, and the regulatory proteins. Regulatory proteins act as both activators (TURN ON) and repressors (TURN OFF) of genes.
The similarities between corepressor and an inducer in negative regulation of an operon are as follows:
- Both are small molecules that bind to the repressor protein present in an operon, causing the repressor to change its shape.
The differences between the roles of a corepressor and an inducer in negative regulation of an operon are as follows:
Characteristics | Corepressor | Inducer |
Role in negative regulation of an operon |
A corepressor binds to the repressor protein, activates it to bind to the operator, and thereby inhibits transcription. For example, tryptophan acts as a corepressor in a trp operon. |
The binding of an inducer to the repressor protein makes it inactive and allows transcription of operon genes. For example, allolactose acts as an inducer in lac operon and binds to the lac repressor; hence, it cannot bind to the operator. |
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