When the interior of a cell is in equilibrium with its environment, which of the following statements best describes the relative movement of molecules that can diffuse through the plasma membrane?
A) There is directed movement of molecules into or out of the cell.
B) There is random movement of molecules into and out of the cell.
C) There is no movement of molecules into or out of the cell.
D) All movement of molecules across the plasma membrane occurs by active transport.

Question

Quizplus · Accepted Answer

When a cell is in equilibrium with its environment, molecules that can diffuse through the plasma membrane continue to move randomly into and out of the cell, but there is no net movement in either direction. This means that the rate of molecules entering the cell is equal to the rate of molecules exiting the cell.

When the Interior of a Cell Is in Equilibrium with Its