Myosin II has a duty ratio of 10 percent, and its step sizeis 8 nm. In contrast, myosin V has a much higher duty ratio (about 70 percent) and takes 36-nm steps as it walks down an actin filament. What differences between myosin II and myosin V account for their different properties? How do the different structures and properties of myosin ll and myosin V reflect their different functions in cells?