Final answer:
A low concentration of GTP would lead to microtubule disassembly or depolymerization, as GTP is necessary for the stabilization and assembly of microtubules.
Step-by-step explanation:
A low concentration of GTP would result in microtubule disassembly or depolymerization. Microtubules are dynamic structures that switch between phases of growth and shrinkage, known as dynamic instability. They assemble at the plus end by adding α/β-tubulin dimers, which are stabilized by GTP. Hydrolysis of GTP to GDP that occurs after dimer addition leads to destabilization of the microtubule lattice, and without a sufficient concentration of GTP, the balance tips towards disassembly. The disassembly of microtubules plays a crucial role in cellular processes such as mitosis, where removal of tubulin subunits from the microtubule ends helps in chromosome segregation.