Question

Oxygen diffuses from blood into cells down its concentration gradient. As cells become more active and oxidative phosphorylation increases in the cell, which of the following occurs?

A) The concentration gradient for oxygen increases and oxygen movement into the cell decreases.

B) The concentration gradient for oxygen and its rate of movement into the cell do not change.

C) The concentration gradient for oxygen increases and oxygen movement into the cell increases.

D) The concentration gradient for oxygen decreases and oxygen movement into the cell decreases.

E) The concentration gradient for oxygen decreases and oxygen movement into the cell increases.

Answer 1

When cells increase oxidative phosphorylation, they use up oxygen more quickly, thereby reducing the concentration of oxygen within the cells. This results in an increased diffusion of oxygen from the blood into the cells because of the enhanced concentration gradient.

The correct option is E) The concentration gradient for oxygen decreases and oxygen movement into the cell increases.

Step-by-step explanation:

As cells become more active and oxidative phosphorylation increases in the cell, the rate at which they utilize oxygen increases. This activity results in a decrease in the intracellular concentration of oxygen because it is being consumed at a high rate.

Since oxygen diffuses from areas of higher concentration to areas of lower concentration, there will be a stronger concentration gradient, meaning there will be a greater difference between the oxygen concentration in the blood and in the cell. Therefore, this drives more oxygen to diffuse from the blood into the cells.

The correct option that reflects this process is E) The concentration gradient for oxygen decreases and oxygen movement into the cell increases.