Chapter 7, Problem 41A

Summary Introduction

To analyze:

How oxygen crosses the plasma membrane if the concentration of oxygen is lower inside the cell than it is outside the cell.

Introduction:

Diffusion is the net movement of particles from their higher concentration to their lower concentration.

In a solution, the dissolved particles collide with each other and moves constantly in random motion, this motion is called Brownian motion.

Explanation of Solution

In the given situation oxygen concentration is higher outside of the cell in respect of inside of the cell.

Here oxygen moves with the concentration gradient that is from its higher concentration to lower concentration. Hence diffusion of oxygen takes place from outside of the cell to inside of the cell through the plasma membrane.

Conclusion

Diffusion is a passive movement and does not require energy. The rate of diffusion depends upon the concentration, temperature, and pressure. When concentration is high, diffusion occurs more quickly because more particles collide.