The Nucleus and its Functional Domains

ID #2026

which is more efficient in terms of time and energy: polycistronism or monocistronism? It seems like prokaryotes waste time in transcribing untranslated regions which appear between regions which will be translated, but then, eukaryotes must transcribe separate strands of DNA for each protein, which costs more energy. Do the costs balance out? Why don't cells just create RNA strands that can be transcribed from the beginning to the end?


It has to do with availability and timing rather than which is more efficient overall. For bacteria, which don't process their mRNAs or send them to a different compartment, ribosomes begin translating protein before the RNA polymerase is even finished transcribing the mRNA.

So it's more efficient for a bacteria to do polycistronic protein synthesis because of this and also regulatory reasons that we'll dive headfirst into later. In eukaryotes, being monocistronic might seem like a hindrance, but remember what we were able to do with those mRNAs before they even got to the nucleus. As it turns out, this is a very efficient way for eukaryotes to make their proteins as well. It's all about making the most of the situation you have, and each type of cell has done the best they can.

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