Question

What provides the energy for ATP synthase? a. the movement of electrons. b. the movement of hydrogen atoms c. the movement of hydrogen ions d. the movement of glucose e. the movement of carbon dioxide

Short answer

Answer: The movement of hydrogen ions (protons).

Step-by-step solution

Understanding ATP synthase

ATP synthase is an enzyme that plays a vital role in the synthesis of ATP (Adenosine Triphosphate). It is responsible for generating ATP from ADP (Adenosine Diphosphate) and inorganic phosphate (Pi) by utilizing energy from a proton gradient across the mitochondrial membrane.

Option A: The movement of electrons

Electrons flow through the electron transport chain, which is coupled to the transport of protons across the mitochondrial membrane. This movement of electrons is essential for creating the proton gradient used to drive ATP synthesis, but it does not directly provide the energy for ATP synthase.

Option B: The movement of hydrogen atoms

Hydrogen atoms consist of a single proton and electron. It is the movement of hydrogen ions (protons) that are involved in ATP synthesis, not the movement of entire atoms.

Option C: The movement of hydrogen ions

This is the correct answer. As electrons pass through the electron transport chain, energy is released, pumping protons (hydrogen ions) from the mitochondrial matrix to the intermembrane space. This creates a proton gradient, and when protons flow back down the gradient through ATP synthase, they provide the energy necessary for ATP synthesis.

Option D: The movement of glucose

Glucose is broken down into pyruvate during glycolysis, and later converted to Acetyl-CoA, which enters the citric acid cycle. Although glucose is crucial for cellular respiration and ATP synthesis, it does not directly provide energy for ATP synthase.

Option E: The movement of carbon dioxide

Carbon dioxide is a product of cellular respiration and is expelled when it is no longer needed. It does not provide energy for ATP synthesis or any related processes.

Conclusion

The correct answer is option C: the movement of hydrogen ions (protons) provides the energy for ATP synthase. The proton gradient established across the mitochondrial membrane is essential to driving ATP synthesis and producing cellular energy.