Final answer:
An active neuron during an action potential has a positive charge, resulting from the influx of sodium ions that change the membrane potential from approximately -70 mV to +30 mV.
Step-by-step explanation:
The active neuron, during an action potential, has a positive charge. This occurs when the neuron receives a signal and sodium ions (Na+) enter the cell, changing the inside charge of the neuron to be more positive compared to the outside. The resting membrane potential of a neuron is approximately -70 mV, indicating a negative charge inside the neuron. However, during the action potential, this charge rapidly reverses to about +30 mV, as the Na+ channels open, allowing the influx of positively charged sodium ions. Following this depolarization, potassium ions (K+) flow out of the cell, which repolarizes the neuron and brings its charge back towards the resting membrane potential. The process of an action potential is akin to a wave that travels down the axon of the neuron. This change in charge is essential for neurons to send signals throughout the nervous system, enabling communication between neurons and the activation of various physiological processes.