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

Transcription in Prokaryotes: - Initiation: RNA polymerase binds to the promoter region of DNA, initiating the process of transcription. - Elongation: RNA polymerase synthesizes RNA in the 5’ to 3’ direction, creating an RNA sequence complementary to the DNA template strand. - Termination: Transcription stops when RNA polymerase reaches the terminator sequence. The newly formed RNA transcript is released. 
Differences between Prokaryotic and Eukaryotic Transcription: 
- RNA Polymerase: - Prokaryotes use a single RNA polymerase for transcription. - Eukaryotes have three distinct RNA polymerases (RNA Polymerase I, II, and III), each responsible for transcribing specific types of RNA. 
- Location: - In prokaryotes, transcription occurs in the cytoplasm, and translation begins immediately after transcription. - In eukaryotes, transcription occurs in the nucleus, and the RNA transcript must undergo processing before it is transported to the cytoplasm for translation. 
- RNA Processing: - Prokaryotic RNA does not require processing and is directly functional as mRNA. - Eukaryotic RNA undergoes capping (addition of a methylated guanosine cap at the 5’ end), tailing (addition of a poly-A tail at the 3’ end), and splicing (removal of non-coding introns and joining of coding exons) to become a mature mRNA.