Final answer:
The assertion is true; Proton-Motive Force (PMF) is indeed the electrochemical gradient across the inner membrane of mitochondria, created by the pumping of hydrogen ions during oxidative phosphorylation.
Step-by-step explanation:
The statement that Proton-Motive Force or PMF is the electrochemical gradient across the inner membrane of mitochondria is A. True. PMF is generated during the process known as oxidative phosphorylation, which is part of cellular respiration. As electrons are transferred through the electron transport chain (ETC), energy is used to pump hydrogen ions (protons) across the inner mitochondrial membrane, from the matrix into the intermembrane space. This creates two gradients: a chemical gradient due to the difference in proton concentration, and an electrical gradient due to the separation of charge.
Together, they form the electrochemical gradient known as the proton-motive force. This force drives protons back through the membrane via ATP synthase, facilitating the production of ATP from ADP and inorganic phosphate.