What is the main function of RNA polymerase II?

The primary function of RNA polymerase II is to transcribe mRNA (messenger RNA) from DNA. mRNA is essential because it serves as the template that carries genetic information from the DNA in the nucleus to the ribosomes in the cytoplasm, where proteins are synthesized. During transcription, RNA polymerase II binds to specific promoter regions of DNA, unwinds the double helix, and synthesizes a complementary strand of RNA, effectively creating a copy of the gene that can be translated into a protein.

The role of RNA polymerase II is fundamental to the expression of genes, allowing the information coded in DNA to be converted into functional products, such as proteins, that perform various roles in the cell. This makes it a key player in the central dogma of molecular biology, where DNA is transcribed to RNA, which is then translated into proteins.