Final answer:
At steady state, the concentration of unpolymerized G-actin indeed equals the critical concentration of polymerization. This dynamic equilibrium is a result of ATP-regulated polymerization and depolymerization processes of actin, facilitating a treadmilling effect.
Step-by-step explanation:
The statement that at steady state, the concentration of unpolymerized G-actin equals to the critical concentration of polymerization is true. At steady state, a dynamic equilibrium is reached where the rate of actin monomers (G-actin) adding to the plus end of actin filaments equals the rate of monomers dissociating from the minus end.
The process of actin polymerization is regulated by ATP hydrolysis. G-actin monomers bound to ATP polymerize faster at the plus end in comparison to the minus end. Once the ATP on the actin monomer is hydrolyzed to ADP, the binding strength and stability of the monomer in the polymer decrease, leading eventually to its dissociation from the filament, especially at the minus end.
The actin cytoskeleton's dynamic nature, involving both polymerization and depolymerization, gives rise to behaviors such as treadmilling, where the polymer appears to move as it adds monomers at the plus end and loses them at the minus end while maintaining overall constant length.