[Campbell Biology P.625] According to Figure 27.7 and its description, how does the motor of... | Practice Question

According to Figure 27.7 and its description, how does the motor of a prokaryotic flagellum primarily generate the force needed for cell propulsion?

  • A: ATP hydrolysis directly powers the rotation of the filament, similar to muscle contraction.
  • B: The diffusion of protons back into the cell through a system of protein rings embedded in the cell wall and plasma membrane provides the rotational force.
  • C: Contraction and relaxation of the flagellar filament itself, powered by changes in its protein conformation, cause the cell to move.
  • D: The motor uses light energy to directly produce mechanical work for propulsion.

Explanation

Figure 27.7's description clearly states: 'The motor of a prokaryotic flagellum consists of a system of protein rings embedded in the cell wall and plasma membrane TEM . The electron transport chain pumps protons out of the cell. The diffusion of protons back into the cell provides the force that turns a curved hook and thereby causes the attached filament to rotate and propel the cell.'