[Campbell Biology P.224] Based on Figure 9.13, which of the following sequences accurately d... | Practice Question
Based on Figure 9.13, which of the following sequences accurately describes the process by which ATP synthase produces ATP?
A: H+ ions enter the catalytic knob, causing the rotor to spin, which then activates the stator to produce ATP.
B: H+ ions bind to binding sites within a rotor, causing it to spin, which in turn causes the internal rod to spin and activate catalytic sites in the knob.
C: The stator spins due to H+ flow, which then rotates the internal rod, activating the catalytic knob to synthesize ATP.
D: H+ ions flow directly into the mitochondrial matrix through the internal rod, leading to ATP synthesis.
Explanation
Figure 9.13 details the steps: H+ ions flow down their gradient, enter a channel in a stator, then enter binding sites within a rotor, changing its shape and causing it to spin. This spinning of the rotor causes an internal rod to spin, which then activates catalytic sites in the knob to produce ATP.