Final answer:
Polycistronic mRNA transcribed from an operon in prokaryotes is translated by multiple ribosomes simultaneously through polysomes, allowing for rapid synthesis of proteins. This efficient system ensures proteins can be quickly produced and accumulated to high concentrations within the cell, responding promptly to cellular needs.
Step-by-step explanation:
Once transcribed from the operon, the single polycistronic mRNA carries the information required to synthesize multiple polypeptides. In prokaryotic cells, these mRNAs can be translated by multiple ribosomes simultaneously, a process facilitated by structures known as polysomes. Each ribosome moves along the mRNA, translating it into a polypeptide chain. This highly efficient process allows the cell to rapidly produce high concentrations of the proteins encoded by the operon genes.
Since the life span of mRNA in prokaryotes is very short, usually only a few minutes, the use of polysomes ensures a continual and high-rate of protein synthesis, as needed by the cell. As soon as transcription begins, ribosomes can attach to the 5' end and start translating even before the entire mRNA strand has been synthesized. This concurrent transcription and translation are unique to prokaryotes, as eukaryotic mRNA undergoes processing in the nucleus before being translated in the cytoplasm.