Question

Bacteria and eukaryotes have many molecular differences due to life history differences. Describe the molecular processes of transcription and the control and regulation of transcription for bacteria and eukaryotes. Explain which differences may be due to life history and why.

Answer 1

The main differences between bacterial and eukaryotic transcriptions are:

• In bacteria, transcription and translation are continous process, but in eukaryotes these are two sepearte process.
• Initiation of transcription is simple in bacteria, but complex in eukaryotes.
• In bacteria, one type of RNA polymerase enzyme but in eukaryotes, three types of enzymes are present for transcription.
• In bacteria, RNA polymerase can recognise but in eukaryotes, it cannot recognize the promoter region.
• In bacteria, termination of transcription by rho independant or dependant mechanisms. In eukaryotes, the mechanism is unknown but possibly due to poly A signal or termination sequence.
• In bacteria, RNA transcript does not undergo post transcriptional modification, but in eukaryotes, RNA trascript undergoes RNA editing or post transcriptional modification.
• Poly-A tail, introns, RNA cap is absent in bacteria, but present in eukaryotes.

The main diffrenece due to life history is the evolution in the promoter region and post transcriptional modifications. The promoter region of the eukaryotes have evolved and thus RNA polymerase cannot recognize the region. In bacteria, translation is comparitively not a complex process, thus it does not require post transcriptional modifications. But, in eukaryotes post transcriptional modifications of RNA transcript helps it to get prepared for translation.