What must be present for transcription to occur?

Transcription is the process by which the genetic information in DNA is copied into messenger RNA (mRNA). For transcription to occur, RNA nucleotides are essential because they are the building blocks that will form the RNA strand complementary to the DNA template strand. During this process, the enzyme RNA polymerase binds to the promoter region of the DNA and catalyzes the assembly of RNA nucleotides into a strand of mRNA corresponding to the sequence of the template DNA strand.

While DNA nucleotides are required to provide the template for transcription and proteins, particularly RNA polymerase, play a crucial role in facilitating the reaction, the direct incorporation of the RNA nucleotides is what enables the formation of the mRNA molecule. Therefore, the presence of RNA nucleotides is critical for the successful transcription of DNA.