The lactose (lac) operon in E. coli is an example of a gene that is repressed when lactose is not available in a cell. In 3-5 sentences, explain what this means in a high school student tone, using correct terminology.
The lactose (lac) operon in E. coli is a group of genes that help the bacteria break down lactose, a sugar found in milk. When lactose is not available in the cell, these genes are "repressed," meaning they are turned off and not actively working. This is because it would be a waste of energy for the cell to produce the proteins needed to break down lactose if there is none around. However, when lactose is present, it acts as a "inducer" and switches on the lac operon, allowing the genes to be transcribed and the necessary proteins to be made.
