What is the role of RNA polymerase in gene expression?

• A. It synthesizes RNA from a DNA template.
• B. It translates RNA into protein.
• C. It replicates DNA.
• D. It modifies histones during chromatin remodeling.

Answer: (A)

RNA polymerase is the enzyme that carries out transcription, converting the information in a DNA sequence into an RNA molecule. It binds to a gene’s promoter, unwinds the DNA, and uses ribonucleotides to synthesize RNA in the 5' to 3' direction, producing the transcript that will guide protein production or function as RNA itself. This step is the bridge between DNA and gene expression, turning genetic instructions into an RNA product that can be used for protein synthesis or other cellular roles. The other activities are carried out by different components: translating RNA into protein is done by the ribosome during translation, DNA replication is performed by DNA polymerase and associated enzymes, and histone modification during chromatin remodeling is part of epigenetic regulation, not RNA polymerase activity.