What does transcription refer to in the context of gene expression?

Transcription refers specifically to the process of copying DNA to RNA, which is a crucial step in gene expression. During transcription, the enzyme RNA polymerase binds to the DNA at a specific region called the promoter and synthesizes a complementary RNA strand based on the DNA template. This RNA strand is often messenger RNA (mRNA), which carries the genetic information from the DNA in the nucleus to the ribosomes in the cytoplasm, where the information can be translated to produce proteins.

This process is essential because it allows the information encoded in the DNA, which resides in the nucleus, to be expressed as functional proteins that perform various roles in the cell. By understanding transcription, it's clear how genes are expressed and regulated, which is fundamental to molecular biology and genetics.