Rho independent terminators
Rho-independent termination (also known as intrinsic termination) is a process carried out in prokaryotic organisms as a mechanism for stopping transcription. The mRNA molecule has a sequence of base pairs with a high proportion of cytosine and guanine bases, these are able to strongly bond to one another with 3 hydrogen bonds forming a RNA duplex in a stable hairpin structure[1] succeeding the hairpin structure is a chain of uracil bases, which only form weak bonds with adenine. The transcription of the uracil sequence is coupled with a protein, located on the RNA polymerase, binding to the hairpin structure causing the RNA polymerase to temporarily stop[2]. The temporary lapse and weak uracil-adenine bonds cause the hairpin structure to unwind and dissociate from the RNA polymerase, thus terminating transcription.