Which of the following is true about the movement of ions across excitable living membranes?
A) Ions always move actively across membranes through leakage channels.
B) Sodium gates in the membrane can open in response to electrical potential changes.
C) Ions always move from an area of higher concentration to an area of lower concentration.
D) Ions always move passively across membranes.

Question

Quizplus · Accepted Answer

The movement of ions across excitable living membranes involves the opening and closing of specific channels in response to electrical and chemical signals. Sodium gates are an example of such channels, which can open in response to depolarization of the membrane. This allows sodium ions to move from an area of higher concentration (outside the cell) to an area of lower concentration (inside the cell). This movement is not always active or passive, as various channels and pumps may be involved in regulating ion movement.

Which of the Following Is True About the Movement of Ions