Discuss different components of prokaryotic gene regulation
The DNA of prokaryotes is organized into a circular chromosome supercoiled in the nucleoid region of the cell cytoplasm. Proteins that are needed for a specific function are encoded together in blocks called operons. For example, all of the genes needed to use lactose as an energy source are coded next to each other in the lactose (or lac) operon.
In prokaryotic cells, there are three types of regulatory molecules that can affect the expression of operons: repressors, activators, and inducers. Repressors are proteins that suppress transcription of a gene in response to an external stimulus, whereas activators are proteins that increase the transcription of a gene in response to an external stimulus. Finally, inducers are small molecules that either activate or repress transcription depending on the needs of the cell and the availability of substrate.
What You’ll Learn to Do
- Understand the basic steps in gene regulation in prokaryotic cells
- Explain the roles of repressors in negative gene regulation
- Explain the role of activators and inducers in positive gene regulation
The learning activities for this section include the following:
- Gene Regulation in Prokaryotes
- Activators and Inducers
- Self Check: Prokaryotic Gene Regulation