Gene expression is the fundamental biological process by which the information encoded within a segment of DNA is used to synthesize a functional gene product, typically a protein. This complex mechanism involves several steps, beginning with transcription, where a specific DNA sequence is transcribed into messenger RNA (mRNA). Subsequently, translation occurs, wherein the sequence of nucleotides on the mRNA serves as the template to direct the assembly of a polypeptide chain composed of amino acids. The regulation of gene expression is critical to life, as it allows specialized cells within a multicellular organism to perform diverse functions by controlling which genes are transcribed and translated, thereby determining the cell's phenotype.