Answer:
A. ATP
B. Yes, protons move with the concentration gradient
C. proton gradient across mitochondrial and chloroplast membrane.
Step-by-step explanation:
A. During cellular respiration and photosynthesis, the free energy produced by the flow of electrons across the mitochondrial membrane and stroma lamellae leads to the formation of ATP molecule.
B. Due to the movement of electron down the reducing equivalent causes the flow of protons across the membrane. This leads to the formation of a concentration gradient.
C. The energy which drives the formation of ATP from ADP comes from the kinetic energy provided by the movement of protons across ATP synthase.
D. The back-flow of protons from intermembrane space of mitochondria to the matrix through ATP synthase and backflow from thylakoid lumen to stroma through ATP synthase add Pi to ADP and form ATP.