Which statement defines gene expression?

• A. Gene expression is the process by which information from a gene is used to synthesize proteins.
• B. Gene expression is the location of a gene on the chromosome.
• C. Expression is the conversion of RNA into protein.
• D. Gene expression is the process by which DNA replicates.

Answer: (A)

Gene expression is the process by which information encoded in a gene is used to make a product, usually a protein. This involves two main steps: transcription, where the gene’s DNA sequence is copied into messenger RNA, and translation, where that mRNA is read by ribosomes to assemble amino acids into a protein. This definition captures how genetic information ultimately leads to a functional product. The other statements describe either where a gene sits on a chromosome, or focus only on converting RNA to protein (omitting transcription), or describe DNA replication (genetic material duplication), none of which define gene expression.