A motif described by this word consists of two antiparallel beta strands linked by a two to five residue loop.
This structure can be generated by reverse Hoogsteen bonding between two long, polypurine domains. In a form of next-gen sequencing, one of these structures containing a sequence of interest is stretched open by a magnetic field. A nucleic acid whose name mentions this structure is delivered by a vector into a cell in which it is processed by Drosha and Dicer, before being loaded onto the RISC. A motif described by this word consists of two antiparallel beta strands linked by a two to five residue loop. The minus strand of the tobacco ringspot virus was where a (*) ribozyme with this structure was first discovered. Either a small, interfering RNA or a short, this type of RNA can be designed to block expression of a specific gene. It's not "stem," but this word denotes a "loop" consisting of unpaired nucleotides on a single stranded RNA or DNA molecule that base-pairs to itself. For 10 points, all of these biological structures share a resemblance to what metal U-shaped object worn in the hair? 
This structure can be generated by reverse Hoogsteen bonding between two long, polypurine domains.
hairpin [or ribbon] 