Final answer:
The hydrolysis of ATP in g-actin subunits within an actin filament plays a key role in actin polymerization and depolymerization. It leads to the destabilization of the filament and enables the growth and shrinkage of actin filaments. This process is involved in various cellular movements.
Step-by-step explanation:
The hydrolysis of ATP in g-actin subunits within an actin filament is an important process in the regulation of actin polymerization and depolymerization. When g-actin monomers bind to ATP, they join the plus end of the actin filament. Within a short period of time, ATP is hydrolyzed to form ADP, reducing the binding strength of the monomers and destabilizing the filament. This dynamic process allows for the growth and shrinkage of actin filaments, leading to cellular movements such as cytoplasmic streaming and muscle contraction.