Here's a breakdown:

* Genes are like blueprints: They contain the instructions for making proteins.

* Proteins are the workhorses of the cell: They perform a wide variety of functions, like building structures, transporting molecules, and catalyzing reactions.

* Gene expression is the process of turning a gene's instructions into a protein: It involves two main steps:

* Transcription: The DNA sequence of the gene is copied into RNA.

* Translation: The RNA is used as a template to build a protein.

* An expressed gene is one that has undergone transcription and translation, leading to the production of a functional protein.

Therefore, an expressed gene is active and contributing to the cell's function.