What is the primary role of structural genes in gene expression?

Structural genes play a crucial role in gene expression by coding for amino acid sequences that make up proteins. These proteins can function as enzymes, structural components of cells, or signaling molecules, among other roles. When a structural gene is expressed, it undergoes transcription to produce messenger RNA (mRNA), which is then translated into a specific sequence of amino acids. This sequence determines the protein's structure and function.

By producing the actual proteins that perform various functions within the cell, structural genes are essential for the overall biological activity, growth, and development of organisms. Unlike regulatory genes, which focus on controlling the expression of other genes, structural genes are directly linked to the synthesis of proteins that execute the cellular functions needed for life.