DNA History, Replication, and Protein Synthesis Practice Test

Transcription termination in bacteria happens via two distinct pathways. In the rho-dependent route, the Rho protein binds the growing RNA and uses its helicase activity to catch up to RNA polymerase, triggering dissociation of the transcription complex. No specific hairpin structure is required here.

In the rho-independent (intrinsic) route, termination relies on the RNA itself forming a hairpin loop followed by a short, uracil-rich tail. The hairpin pauses RNA polymerase, and the weak RNA-DNA hybrid in the U-rich region promotes release of the transcript.

So the statement that correctly matches these mechanisms is that rho-dependent termination uses the Rho helicase, while rho-independent termination uses a hairpin loop and terminator. The other options misassign the roles—rho-independent does not depend on Rho, and rho-dependent is not driven by RNase or solely by polymerase pausing without Rho.