Question

(b) Explain the process of transcription in prokaryotes. How is it different from transcription in eukaryotes?

Hint:

Transcription in prokaryotes is simpler and faster due to the absence of a nucleus and RNA processing, unlike the complex and compartmentalized transcription in eukaryotes.

Answer 1

Prokaryotic Transcription Stages: - Initiation: RNA polymerase attaches to the DNA's promoter region to start transcription. - Elongation: RNA polymerase builds an RNA strand from 5’ to 3’, creating a sequence that matches the DNA template strand. - Termination: Transcription ceases when RNA polymerase reaches the terminator sequence, releasing the completed RNA molecule.
Key Distinctions: Prokaryotic vs. Eukaryotic Transcription: 
- RNA Polymerase Type: - Prokaryotes utilize one RNA polymerase. - Eukaryotes employ three distinct RNA polymerases (I, II, and III), each transcribing different RNA types. 
- Cellular Location: - Prokaryotic transcription occurs in the cytoplasm, with translation commencing immediately. - Eukaryotic transcription takes place in the nucleus, requiring RNA processing before cytoplasmic translation. 
- RNA Modification: - Prokaryotic RNA is directly functional as mRNA without processing. - Eukaryotic RNA undergoes 5’ capping, 3’ poly-A tailing, and intron removal (splicing) to form mature mRNA.