What is a primary product of transcription?

The primary product of transcription is messenger RNA (mRNA). During the process of transcription, a segment of DNA is used as a template to synthesize a complementary strand of RNA. This process takes place in the nucleus of eukaryotic cells. The enzyme RNA polymerase binds to the DNA at a specific region, unwinds the DNA strands, and synthesizes mRNA by incorporating ribonucleotides that base-pair with the DNA template.

mRNA serves as the intermediary molecule that carries the genetic information from DNA to the ribosome, where it serves as a template for protein synthesis during translation. This role of mRNA is crucial as it enables the genetic instructions encoded in DNA to be expressed as proteins, which are essential for numerous cellular functions.

In contrast, protein is the end product of the translation process, which occurs after transcription, while amino acids are the building blocks of proteins. Ribosomal RNA (rRNA) is involved in the formation of ribosomes and does not directly result from the transcription of mRNA. Thus, messenger RNA is the correct answer as it is the direct outcome of the transcription process.