Final answer:
The three stages of transcription are initiation, elongation, and termination. The product of transcription is mRNA. Post-transcriptional modifications occur after transcription in eukaryotes.
Step-by-step explanation:
The three stages of transcription of DNA are initiation, elongation, and termination. During initiation, RNA polymerase binds to a gene's promoter region and unwinds the DNA. Elongation involves the addition of nucleotides to the mRNA strand by RNA polymerase. Termination occurs when RNA polymerase reaches a stop sequence, detaches from the DNA, and the mRNA strand is complete.
The product of transcription is mRNA (messenger RNA), which carries the genetic code from DNA to the ribosomes for protein synthesis. After transcription, there is a fourth step known as post-transcriptional modifications, which occur in eukaryotes where the mRNA undergoes additional processing before it leaves the nucleus. This may include splicing, editing, and polyadenylation, allowing a single gene to produce multiple proteins.