Final answer:
Transcription involves three stages: initiation, elongation, and termination, with RNA polymerase being the key protein involved. Promoters direct the binding of RNA polymerase, which then creates an mRNA molecule carrying the genetic code.
Step-by-step explanation:
The three stages of transcription include: initiation, elongation, and termination. The main protein responsible for transcription is RNA polymerase. During initiation, RNA polymerase binds to a specific sequence on DNA known as the promoter. The DNA strands unwind, allowing RNA polymerase to align nucleotides to create a complementary RNA strand.
During elongation, the RNA polymerase moves along the DNA template strand, adding nucleotides to the growing RNA strand. In termination, signals on the DNA prompt the RNA polymerase to release the completed RNA molecule, which then undergoes processing to become mature mRNA.
Promoters are key to the transcription process because they determine the exact location where RNA polymerase should bind to initiate transcription. The final product of transcription is mRNA (messenger RNA), which carries the genetic code from DNA to the ribosome where protein synthesis takes place.