Question

How do prokaryotes use operons to control genes?

Answer 1

Gene regulation in prokaryotes:

1. Many bacterial genes are grouped into operons, which are groups of related genes that are translated into a single mRNA that codes for two or more proteins.
2. The ability to control the activity of an operon (rather than numerous single genes producing single proteins) allows for better coordination of the synthesis of several proteins at the same time.
3. The controlled lac operon in E. coli encodes three enzymes involved in lactose metabolism (an alternative nutrient to glucose).
4. An operon (or a single gene) can be regulated by either repression or induction.
5. When a tiny metabolite binds to a regulatory repressor or inducer protein in a cell, the protein undergoes an allosteric change that permits it to bind to or unbind from a regulatory DNA sequence.
6. Such regulation will be shown in the lac and trp operons. Lac operon gene regulation exemplifies both gene repression and activation.