When blood supplies oxygen and food to a cell surface and these molecules diffuse across,we might expect some "resting time." However,if we inspected most cell membranes in a living human body,we would find a nearly continuous flow of substances back-and-forth across the plasma membrane.Which of the following is not a reason why?
A)Cell metabolism is constantly using up oxygen and raw materials; this lowers their concentration so more will diffuse into the cell.
B)Cell metabolism is constantly producing waste molecules; this increases their concentration so more will diffuse out of the cell.
C)Cells produce useful secretions; this increases their concentration and more will diffuse out of the cell.
D)Cell metabolism constantly produces carbon dioxide in respiration; this increases its concentration so more will diffuse out of the cell.
E)Cells are living entities and in order to live can never "rest."

Question

Quizplus · Accepted Answer

Cells can have periods of low activity or rest, but the continuous flow of substances is due to ongoing metabolic processes, not because cells can never rest.

When Blood Supplies Oxygen and Food to a Cell Surface