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B. ATP synthase. The purpose of the hydrogen gradient is to take advantage of molecules' tendency to move from areas of higher concentration to areas of lower concentration. ATP synthase lets hydrogen ions flow through it to the matrix, and the energy from this flow is used by ATP synthase to synthesize ATP.
Answer:
They both have cell membranes.
Explanation:
The prokaryotes and eukaryotes have cell membranes that enclose the cell organelles. The prokaryotes lack nuclear membrane, membrane bound organelles like the chloroplasts and also golgi apparatus.