The inside of the neuron has a lower concentration of positive ions than the outside of the neuron. Is the membrane potential positive or negative?

Verified step by step guidance

1. Understand the concept of membrane potential: Membrane potential is the electrical potential difference across a cell's plasma membrane, resulting from the distribution of ions (charged particles) on either side of the membrane.
2. Identify the key ions involved: In neurons, the key ions include sodium (Na+), potassium (K+), and chloride (Cl-). Sodium and potassium ions are positively charged, while chloride ions are negatively charged.
3. Recognize the distribution of ions: Typically, there is a higher concentration of Na+ outside the neuron and a higher concentration of K+ inside the neuron. This difference in ion concentration contributes to the membrane potential.
4. Relate ion concentration to membrane potential: Since the inside of the neuron has a lower concentration of positive ions (Na+ and K+) compared to the outside, this creates an electrical gradient. More positive charges outside the neuron make the inside relatively negative.
5. Determine the sign of the membrane potential: Given the higher concentration of positive ions outside and a lower concentration inside, the inside of the neuron is negatively charged relative to the outside. Thus, the membrane potential is negative.

Key Concepts

Membrane Potential

Membrane potential refers to the electrical potential difference across a cell membrane, primarily due to the distribution of ions. In neurons, this potential is crucial for transmitting signals. A negative membrane potential indicates that the inside of the neuron is more negatively charged compared to the outside, which is typically the case at rest.

Ion Concentration Gradient

An ion concentration gradient exists when there is a difference in the concentration of ions across a membrane. In neurons, the inside has a lower concentration of positive ions (like sodium) compared to the outside. This gradient is essential for the generation of action potentials and influences the overall membrane potential.

Resting Membrane Potential

The resting membrane potential is the baseline electrical charge of a neuron when it is not actively transmitting signals, typically around -70 mV. This negative value results from the higher concentration of negatively charged ions and proteins inside the neuron, along with the selective permeability of the membrane to different ions, particularly potassium.