  We consider a randomly flashing ratchet, where the potential acting can be
switched to another at random. Using coupled Fokker-Planck equations, we
formulate the expressions of quantities measuring dynamics and thermodynamics.
Extended numerical calculations present how the potential landscapes and the
transitions affect the motility and energetics. Load-dependent velocity and
energetic efficiency of motor proteins, kinesin and dynein, further exemplify
the randomly flashing ratchet model. We also discuss the system with two
shifted sawtooth potentials.
