Question

the negative resting potential of a neuron is due to
diffusion of sodium ions into the cell
diffusion of potassium ions into the cell
diffusion of sodium ions out of the cell
diffusion of potassium ions out of the cell

question 12
which is a junction between two neurons?
sodium gate
node
synapse
all of the choices
schwann cell

Explanation:

• For the first question:
• Neurons have a higher concentration of \(K^{+}\) inside and \(Na^{+}\) outside at rest.
• \(K^{+}\) diffuses out (down its concentration gradient), leaving the inside more negative (since large anions are trapped inside).
• For the second question:
• A synapse is the junction between two neurons where communication occurs (e.g., chemical synapse with neurotransmitters).
• A sodium gate is related to ion flow in neuron membranes (not a junction).
• A node (of Ranvier) is part of a myelinated axon (for saltatory conduction, not a neuron - neuron junction).
• Schwann cells are glial cells that myelinate peripheral axons (not a junction).

Answer:

• First question: diffusion of potassium ions out of the cell.
• Second question: synapse.