Diagram and explain how the inducibility of a gene—for instance in response to an environmental cue—could be mediated by an activator. Then show how it could be mediated by a repressor.

Key Concepts

Gene Inducibility

Gene inducibility refers to the ability of a gene to be expressed in response to specific environmental signals or cues. This process is crucial for organisms to adapt to changing conditions, allowing them to produce necessary proteins only when needed. Inducible genes are often regulated by proteins that can enhance or inhibit their transcription.

Activator Proteins

Activator proteins are transcription factors that bind to specific DNA sequences near a gene, promoting its transcription. They enhance the recruitment of RNA polymerase to the gene's promoter, facilitating the initiation of transcription. Activators can respond to environmental signals, leading to increased gene expression when conditions are favorable.

Repressor Proteins

Repressor proteins are regulatory proteins that bind to DNA and inhibit gene transcription. They can block the binding of RNA polymerase to the promoter or recruit other proteins that compact the DNA, making it less accessible. Repressors play a critical role in gene regulation by preventing unnecessary gene expression, especially in response to unfavorable environmental conditions.