Question

True/False: Normal polycistronic RNA's can be terminated by either intrinsic or factor-dependent terminators located downstream of the last coding region (in the 3'-untranslated region; 3'-UTR).

A. True
B. False

Answer 1

The statement is True. Normal polycistronic RNA's can be terminated by rho-dependent and rho-independent mechanisms located downstream of the last coding region in the 3'-UTR, affecting the mRNA stability and translation.

Step-by-step explanation:

The statement Normal polycistronic RNA's can be terminated by either intrinsic or factor-dependent terminators located downstream of the last coding region (in the 3'-untranslated region; 3'-UTR) is True. In bacteria, polycistronic RNAs can end transcription through two main mechanisms: rho-dependent termination and rho-independent termination, also known as intrinsic termination.

Rho-dependent termination is controlled by the rho protein, which unwinds the RNA-DNA hybrid near the end of a gene after polymerase pauses at a run of G nucleotides on the DNA template. In rho-independent termination, a hairpin loop is formed in the RNA when a GC-rich region is transcribed, followed by a series of uracil residues, causing the RNA polymerase to stall and dissociate from the DNA.

The 3'-untranslated region (3'-UTR) is a part of an mRNA that is not translated into protein, but can play a role in regulation of mRNA localization, stability, and protein translation. RNA-binding proteins, or RBPs, can bind to these untranslated regions, affecting the stability of the RNA molecule.