 The process of adding or removing monomers depends on the concentration of αβ-tubulin dimers in solution in relation to the critical concentration, which is the steady state concentration of dimers at which there is no longer any net assembly or disassembly at the end of the microtubule.If the dimer concentration is greater than the critical concentration, the microtubule will polymerize and grow.If the concentration is less than the critical concentration, the length of the microtubule will decrease.