Final answer:
Dynein is the motor protein responsible for the bending motion of cilia and flagella, using ATP to slide microtubules against each other within the axoneme.
Step-by-step explanation:
The motor protein that drives the bending movements of cilia and flagella is known as dynein. Dynein uses the energy from ATP hydrolysis to walk along the B tubules of an adjacent doublet in microtubule structures. This action causes the sliding of microtubules against one another resulting in the bending and motion of the axoneme, which is fundamental to the movement of cilia and flagella. It's important to note that this movement is regulated by the flexible nexin and radial spoke attachments that make sure the microtubule sliding translates into bending rather than completely sliding apart. Furthermore, motor proteins such as kinesin also play roles in intracellular transport along microtubules, but dynein is specifically key for the bending motions of cilia and flagella.