Action Potential and Ion Channels

What is a characteristic of excitable cells?

• They are only found in plants.

• They can generate electrical signals.

• They are responsible for photosynthesis.

• They only store energy.

What is the main role of the cell membrane in relation to ions?

• To produce ions for the cell.

• To prevent all ions from entering or leaving.

• To control the movement of ions in and out of the cell.

• To convert ions into energy.

How does the sodium-potassium pump contribute to the cell's resting membrane potential?

• It moves more positive ions into the cell than out.

• It moves more negative ions out of the cell than in.

• It moves more positive ions out of the cell than in, making the inside more negative.

• It moves an equal number of positive and negative ions.

What does the "all-or-nothing" principle mean for an action potential?

• It can only be partially triggered.

• It either fires completely or not at all.

• Its strength varies depending on the stimulus.

• It can be stopped once it starts.

What happens during the rising phase of an action potential?

• Potassium ions leave the cell.

• Sodium channels close.

• Sodium ions enter the cell.

• The membrane potential becomes more negative.

Which type of ion channel opens in response to a physical stimulus like touch?

• Ligand-gated ion channel

• Voltage-gated ion channel

• Mechanically-gated ion channel

• Sodium-potassium pump

What is the main purpose of the refractory period during an action potential?

• To allow the neuron to fire continuously.

• To prevent the action potential from moving forward.

• To ensure the action potential travels in one direction.

• To increase the speed of the action potential.