Final answer:
The statement that the TPP riboswitch is less susceptible to cleavage by ribonuclease when bound to thiamine pyrophosphate is true. Riboswitches change conformation upon binding to specific molecules, which can protect the mRNA from degradation and regulate gene expression.
Step-by-step explanation:
The TPP riboswitch is less susceptible to cleavage by ribonuclease only when bound to thiamine pyrophosphate. This statement is true. Riboswitches are regulatory segments of RNA that can influence gene expression in response to specific molecular signals, such as the presence of a metabolite like thiamine pyrophosphate (TPP). When bound to TPP, the riboswitch assumes a conformation that is protective against enzymatic degradation by ribonucleases. This change in structure often results in the stabilization of the mRNA molecule, preventing its premature breakdown and therefore, allowing the subsequent translation process to occur properly.
Understanding the riboswitch mechanism is critical as it highlights the sophisticated methods of genetic regulation in prokaryotic organisms. Moreover, this insight can have implications in the development of new antibiotics or synthetic biology tools by targeting specific riboswitches to modulate gene expression.