Membranes in living cells, including those in humans, are characterized by a separation of charge across the membrane. effectively, the membranes are thus charged capacitors with important functions related to the potential difference across the membrane. is energy required to separate these charges in living membranes and, if so, is its source the metabolization of food energy or some other source?

Yes, energy is required to separate the charges. Mostly, the inner of the cell membrane is negatively charged compared to the outside. When the cell becomes depolarized, ions, especially, Sodium ions, are pumped out by active transportation to restore resting potential. Active transport requires energy from ATP powered by food metabolism.

it has one origin of replication, but it proceeds in two directions - d)