Final answer:
The conversion of a riboswitch from one conformation to another is triggered by the binding of a small molecule to it. This structural alteration can regulate gene expression by influencing mRNA synthesis and protein synthesis.
Step-by-step explanation:
The conversion of a riboswitch from one conformation to another is due to binding of a small molecule. A riboswitch is a segment of mRNA that can change its structural formation when a small metabolite binds to it. This binding alters the RNA structure, which can influence gene expression by either allowing or preventing the completion of mRNA synthesis and protein synthesis. Riboswitches are found primarily in prokaryotes and play a role in regulating the response to intracellular conditions. When the cell has a sufficient amount of a product, like guanine, the riboswitch can bind the excess product. This causes a change in the mRNA structure leading to the prevention of further transcription or translation of the mRNA, minimizing the production of that metabolite.