Final answer:
Cell activities often depend on the conformational changes of motor proteins like myosin, dynein, and kinesin, which are ATPases using energy from ATP hydrolysis to move within the cell.
Step-by-step explanation:
Activities in cells are based on dynamic, mechanical changes within cells, many of which are initiated by changes in the conformation of "motor" proteins such as myosin, dynein, and kinesin. These motor proteins are ATPases that harness the free energy from ATP hydrolysis to provoke structural changes resulting in movement along cellular structures like microtubules and microfilaments. This energized interaction between actin and motor proteins, as well as the ATP-dependent mechanism by which myosin operates, are essential for processes such as cell motility, cargo transport, and the cell's mechanical response to its environment. These dynamic changes within cells distinguish them from static entities and are crucial for diverse cellular functions.