Final answer:
The charge difference across a membrane indeed produces the membrane potential, which is essential for nerve signal transmission and cellular functions. This potential difference is maintained by the active transport of ions, requiring significant energy mostly derived from the metabolism of food.
Step-by-step explanation:
The statement that the charge difference across a membrane produces the membrane potential is true. The membrane potential is a result of the separation of charges across the plasma membrane, primarily due to the active transport of ions such as sodium (Na+) and potassium (K+). A potential difference, typically about -70 mV in the resting state, arises because of the relatively negative charge inside the cell compared to the outside. The neuron's resting potential changes during stimulation, allowing Na+ ions to enter the cell, thus momentarily reversing the membrane potential which is essential for the generation of nerve signals.
The electric field resulting from this charge separation is exceptionally strong, given the membrane's narrow thickness (approximately 7 to 10 nm). This potential difference across the cell membrane is crucial for cellular functions, especially in nerve and muscle cells, and the cell uses a significant portion of its energy to maintain it. Energy for separating these charges comes from the metabolization of food energy.
Overall, the membrane potential is key to the conduction of electrical impulses along nerve cells and plays a fundamental role in various cellular activities, influencing the cell structure and permeability.