Final answer:
Eukaryotic pre-mRNA undergoes processing steps including 5' capping, poly-A tail addition, and splicing, critical for mRNA stability and protein synthesis. Prokaryotic mRNA lacks these modifications, has a shorter half-life, and does not undergo splicing due to the absence of introns.
Step-by-step explanation:
After transcription, eukaryotic pre-mRNAs require several critical processing steps before they are fully mature and can participate in protein synthesis. These steps include: adding a 5' methylguanosine cap, poly-A tail addition at the 3' end, and splicing, which involves the removal of introns and rejoining of exons. The 5' cap and poly-A tail are essential for protecting the mRNA from degradation, aiding in its export from the nucleus, and ensuring the proper initiation of translation. Introns, which do not encode protein, are removed to create a continuous coding sequence that can be correctly read by ribosomes for protein synthesis.
Eukaryotic mRNAs are extensively processed and are longer-lived, lasting several hours, compared to prokaryotic mRNAs, which may last mere seconds. This longer life span is due to the additional modifications eukaryotic mRNAs receive. Prokaryotic mRNAs lack a 5' cap and poly-A tail and are generally not spliced, as their genes do not typically contain introns. Additionally, in prokaryotes, transcription and translation can occur simultaneously, which is not the case in eukaryotes where transcription and subsequent processing occur in the nucleus, and translation takes place in the cytoplasm.