Gene expression regulation differences between prokaryotes and eukaryotes; which is a prokaryotic example?

Gene expression regulation differences between prokaryotes and eukaryotes; which is a prokaryotic example?

• A. Enhancers and chromatin remodeling.
• B. Transcription factors.
• C. Lac operon.
• D. RNA interference.

Answer: (C)

In prokaryotes, gene expression is often organized into operons—clusters of genes with a single promoter that are transcribed together, so related functions are turned on or off as a unit. The Lac operon is the classic prokaryotic example. It groups the genes needed to metabolize lactose under one promoter and regulatory region. A repressor can bind to the operator to block transcription, but when lactose is present it is converted to a molecule that inactivates the repressor, allowing transcription to proceed. There’s also an activator system (CAP and cAMP) that helps boost transcription when glucose is scarce. This setup—coordinate control of multiple genes in one transcriptional unit—embodies how prokaryotes regulate gene expression. In contrast, enhancers and chromatin remodeling, general transcription factors, and RNA interference are features more associated with eukaryotic regulation, which relies on chromatin structure and post-transcriptional steps.

In prokaryotes, gene expression is often organized into operons—clusters of genes with a single promoter that are transcribed together, so related functions are turned on or off as a unit. The Lac operon is the classic prokaryotic example. It groups the genes needed to metabolize lactose under one promoter and regulatory region. A repressor can bind to the operator to block transcription, but when lactose is present it is converted to a molecule that inactivates the repressor, allowing transcription to proceed. There’s also an activator system (CAP and cAMP) that helps boost transcription when glucose is scarce. This setup—coordinate control of multiple genes in one transcriptional unit—embodies how prokaryotes regulate gene expression. In contrast, enhancers and chromatin remodeling, general transcription factors, and RNA interference are features more associated with eukaryotic regulation, which relies on chromatin structure and post-transcriptional steps.