Final answer:
5' prime capping occurs during the transcription phase of mRNA synthesis, involving the addition of a protective cap that aids in mRNA stability and translation initiation.
Step-by-step explanation:
5' Prime Capping in mRNA Synthesis
The process of 5' prime capping occurs early in the synthesis of mRNA, specifically during the transcription phase when the pre-mRNA is still being synthesized. An enzyme known as capping enzyme adds a 7-methylguanosine cap to the 5' end of the nascent RNA transcript through a 5'-5' triphosphate linkage. This cap functions as a crucial protective group, protecting the mRNA from enzymatic degradation in the cytoplasm.
Furthermore, the cap is recognized by key protein factors that assist in initiating translation by the ribosome, ensuring the correct processing and expression of the genetic information. In summary, the 5' cap is vital for mRNA stability and efficient protein synthesis.