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

Question

Quizplus · Accepted Answer

Sodium gates in the membrane can open in response to electrical potential changes, allowing the movement of sodium ions across the membrane. This process is essential for the propagation of nerve impulses and muscle contractions in excitable living membranes. Therefore, choice D is the correct option. Choices A and B are incorrect because ions can move both actively and passively across membranes, depending on the type of ion and the specific conditions. Choice C is incorrect because ions can move from lower to higher concentrations if energy is provided for the transport.

Which of the Following Is True About the Movement of Ions