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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- Describe what happens to the trp operon as the cell uses up its store of tryptophan.arrow_forwardExplain how the trp operon is regulated by trp repressor and by attenuation.arrow_forwardDefine the following in the context of operons: a. positive control b. give an example of an operon that is under positive control c. negative control d. give an example of an operon that is under negative control e. repressor f. give an example of a repressor molecule g. activator h. give an example of an activatorarrow_forward
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- Which of these BEST DESCRIBE tryptophan in the Trp Operon? A. Acts as a corepressor B. Acts as a coactivator C. Acts as an inducer D. Acts as an enhancerarrow_forwardFalsify and explain why each answer is right or wrong in detail.. How does the Trp operon work? A. Binding of Trp to a repressor protein allows the repressor to bind DNA B. Binding of a regulatory protein to the operator is required for transcription C. Binding of Trp to RNA polymerase represses transcription D. Binding of RNA polymerase to the operator is required for transcriptionarrow_forwardExplain and give examples of Inducible & Repressible Operons. Describe what types of protein products or pathways each controls, and explain why this is appropriate. ** Illustrate and EXPLAIN both Positive and Negative Control!! **arrow_forward
- Biology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage Learning