Final answer:
Eukaryotic mRNA undergoes processing, including the addition of a 5' cap and a poly-A tail to protect against degradation and aid in translation and transport. Prokaryotes don't require these modifications because they have no nucleus, and their mRNA is translated immediately without the need for transport.
Step-by-step explanation:
Eukaryotic cells have different requirements than prokaryotic cells when it comes to mRNA processing. In eukaryotes, the primary transcripts undergo several processing steps, whereas prokaryotic RNA is often ready to be translated as soon as it is transcribed. For eukaryotes, both the 5' cap and the poly-A tail play crucial roles in protecting the mRNA from degradation and assisting in the transport of the mRNA from the nucleus to the cytoplasm where it can be translated.
The 5' cap is added to the 5' end of the pre-mRNA during transcription and is composed of a 7-methylguanosine moiety. This cap is recognized by proteins involved in the initiation of translation and helps to protect the mRNA from degradation. The poly-A tail is added to the 3' end after transcription and typically consists of around 200 adenine residues. This modification not only increases mRNA stability but also facilitates its export from the nucleus and assists in the initiation of translation.
Prokaryotes do not require these modifications because their mRNA does not have to be transported out of a nucleus, and their cellular processes allow for immediate translation of the transcribed RNA. Therefore, prokaryotic mRNA does not have introns to be spliced out and does not typically feature a 5' Cap or poly-A tail.