The significance of gene expression in biology lies in its fundamental role in determining how genetic information is translated into functional products, primarily proteins. Gene expression is a tightly regulated process involving transcription and translation, allowing cells to respond to internal and external signals. Variations in gene expression levels can lead to differences in cell types, characteristics, and functions, thereby influencing an organism's phenotype. Understanding gene expression is crucial for comprehending developmental processes, physiological responses, and the mechanisms underlying genetic disorders and diseases, as well as for developing targeted therapies.