RNA is a structural molecule whose three-dimensional architecture stores biological information, interacts with cellular proteins, catalyzes chemical reactions, and coordinates an infectious life cycle. It carries out these actions through precise three-dimensional structures capable of recognizing and binding other molecules with high specificity. What is less widely appreciated is that RNA achieves this wide range of interactions not despite its constant movement, but becau

A viroid is smaller than a virus. It is a strand of RNA with 246 to 467 nucleotides in length. It is single-stranded, with extensive self-bonding between bases and forms into a fluctuating rod-like or branched structure. It does not produce proteins, has no capsid or membrane, and hijacks cell enzymes to copy itself with a circular rolling mechanism. Thus far, viroids are only found in plants. Also, they can contain ribozymes, which are RNA regions that are able to accuratel