EVERYDAY SCIENCE

Detailed explanation-1: -A neuron at rest is negatively charged because the inside of a cell is approximately 70 millivolts more negative than the outside (−70 mV); this number varies by neuron type and by species.

Detailed explanation-2: -What happens when a neuron is at rest? In the resting state, there is no signal passing through the neuron. However, even in this state, the neuron is electrically active. Because of how ions are moving across the cell membrane, the inside of the neuron is more negative than the fluid that surrounds it.

Detailed explanation-3: -In the axon, the distribution of ions during the resting potential causes there to a difference in the amount of positively and negatively charged ions on the inside of the axon relative to the outside of the axon. This difference is measured as a voltage.

Detailed explanation-4: -At rest, a typical neuron has a resting potential (potential across the membrane) of −60 to −70 millivolts. This means that the interior of the cell is negatively charged relative to the outside.

Detailed explanation-5: -Answer: The resting membrane potential is negative because the neuron is filled with negatively charged molecules, such as proteins, that do not traverse the cell membrane through channels the way ions do.