Final answer:
Gene expression is the process of synthesizing a protein or functional RNA from a gene. It involves transcription and translation and is crucial for cells to function properly.
Step-by-step explanation:
Gene expression is the process by which a gene is used to synthesize a protein or functional RNA. It involves two main steps: transcription, where the DNA is transcribed into RNA, and translation, where the mRNA is used as a template to synthesize a protein. This process is essential for cells to function properly and control the production of proteins at the right time and in the right amount.