Practice question

Intrinsic terminators, also called rho-independent, consist of GC-rich palindrome transcribed into RNA that folds into stable hairpin stem-loop followed by uridine-rich tract of four to eight U residues. Hairpin forms within RNA exit channel causing polymerase pausing, while weak rU-dA hybrid in active center destabilizes elongation complex without requiring additional factors. Spontaneous release of transcript and polymerase occurs due to low thermodynamic stability. Rho-dependent extrinsic terminators lack this hairpin and require Rho hexameric helicase ATPase tracking along cytosine-rich rut sites to pull RNA out.