Question

Polycistronic mRNAs encode

A) one product that is alternatively spliced.
B) more than one protein.
C) multiple cis elements.
D) exclusively eukaryotic proteins.
E) None of these.

Answer 1

Polycistronic mRNAs encode more than one protein and are commonly found in prokaryotes, allowing the translation of multiple proteins from a single RNA molecule.

Step-by-step explanation:

Polycistronic mRNAs are known to encode more than one protein. These kinds of mRNA molecules are typically found in prokaryotes, where genes encoding proteins of related functions can often be transcribed together under the control of a single promoter. The result is the formation of a polycistronic mRNA molecule that sequentially encodes multiple polypeptides, allowing a single RNA transcript to be translated into different protein products.

This is in contrast to eukaryotic cells, where most mRNA molecules are monocistronic, meaning each mRNA encodes only a single polypeptide. Alternative splicing is a process found in eukaryotes where a single pre-mRNA can be processed in different ways to produce multiple mature mRNA variants, encoding different proteins, but this is different from the concept of polycistronic mRNAs.