What would most likely occur if the repressor protein could not bind to the operator?

What would most likely occur if the repressor protein could not bind to the operator?

• A. Gene transcription would be inhibited.
• B. Gene transcription would be activated.
• C. No effect on gene transcription.
• D. Only certain genes would be expressed.

Answer: (B)

If the repressor protein is unable to bind to the operator, it means that the mechanism normally preventing transcription of the associated gene is disrupted. In typical gene regulation scenarios, a repressor protein binds to the operator region of DNA, blocking RNA polymerase from transcribing the gene into mRNA. When the repressor cannot attach to the operator, this blockage is removed, allowing RNA polymerase access to the promoter and facilitating the transcription of the gene. This situation usually results in an increase in gene expression because the absence of the repressor means that the gene is no longer being suppressed. Consequently, the transcription of that gene would be activated, leading to higher levels of mRNA and subsequently increased production of the corresponding protein. Therefore, the inability of the repressor to bind effectively activates the gene, allowing for its expression.

If the repressor protein is unable to bind to the operator, it means that the mechanism normally preventing transcription of the associated gene is disrupted. In typical gene regulation scenarios, a repressor protein binds to the operator region of DNA, blocking RNA polymerase from transcribing the gene into mRNA. When the repressor cannot attach to the operator, this blockage is removed, allowing RNA polymerase access to the promoter and facilitating the transcription of the gene.

This situation usually results in an increase in gene expression because the absence of the repressor means that the gene is no longer being suppressed. Consequently, the transcription of that gene would be activated, leading to higher levels of mRNA and subsequently increased production of the corresponding protein. Therefore, the inability of the repressor to bind effectively activates the gene, allowing for its expression.