Multiple select. Choose all that apply: During the repolarization phase of an action potential, which of the following are true:
Group of answer choices
chemically-gated ion channels are open
voltage-gated potassium channels are open
sodium ions diffuse into the cell
voltage-gated sodium channels are closed
potassium ions diffuse out of the cell
- voltage-gated potassium channels are open
- voltage-gated sodium channels are closed
- potassium ions diffuse out of the cell
During the repolarization phase of an action potential, the following are true:
- Voltage-gated potassium channels are open.
- Potassium ions diffuse out of the cell.
Therefore, the correct selections are:
- Voltage-gated potassium channels are open.
- Potassium ions diffuse out of the cell.
To determine which of the statements are true during the repolarization phase of an action potential, we need to understand the changes that occur during this phase.
During the repolarization phase, the cell membrane potential is returning to its resting state after depolarization. Here are the correct statements:
1. Voltage-gated potassium channels are open: During repolarization, the voltage-gated potassium channels open, allowing the flow of potassium ions out of the cell. This outflow of positively charged potassium ions helps restore the negative charge inside the cell.
2. Voltage-gated sodium channels are closed: After depolarization, the voltage-gated sodium channels become inactivated, preventing the flow of sodium ions into the cell. This closure of sodium channels is essential for the repolarization phase.
3. Chemically-gated ion channels may or may not be open: The opening or closing of chemically-gated ion channels is not specifically associated with the repolarization phase. These channels may be involved in other processes but are not directly related to repolarization.
4. Sodium ions diffuse into the cell: This statement is incorrect. During the repolarization phase, sodium ions are not diffusing into the cell. Instead, the voltage-gated sodium channels are closed, preventing the entry of sodium ions.
5. Potassium ions diffuse out of the cell: This statement is correct. During repolarization, the voltage-gated potassium channels are open, allowing the diffusion of potassium ions out of the cell, which contributes to the restoration of the resting membrane potential.
Therefore, the correct answers are:
- Voltage-gated potassium channels are open.
- Voltage-gated sodium channels are closed.
- Potassium ions diffuse out of the cell.
Chemically-gated ion channels being open or closed and sodium ions diffusing into the cell are not characteristics specifically associated with the repolarization phase.