Transcription is the first step of gene expression that involves the formation of RNA molecules from DNA.
Transcription in prokaryotes:
Initiation – In this step, RNA polymerase enzyme and initiation factor binds at the promoter of DNA sequence and begin transcription.
Elongation – In this step RNA polymerase, enzyme nucleoside triphosphate behaves as a substrate and polymerises the nucleotides of templates as a complementary strand.
Termination – In this step rho, a terminator factor replaces the initiation factor at the DNA sequence termination point. At this stage RNA and RNA polymerase, an enzyme is separated with rho factor.
The difference in the process of transcription in prokaryotes and eukaryotes:
- Transcription occurs in the nucleus in eukaryotes while it occurs in the cytoplasm in the prokaryotes.
- RNA processing is required in eukaryotes as its structural gene is monocistronic whereas it is not required in prokaryotes because its structural gene is polycistronic in nature.