You are monitoring the diffusion of a molecule across a membrane. Which of the following will result in the fastest rate of diffusion?
A) An internal concentration of 5 percent and an external concentration of 60 percent
B) An internal concentration of 60 percent and an external concentration of 5 percent
C) An internal concentration of 35 percent and an external concentration of 40 percent
D) An internal concentration of 50 percent and an external concentration of 50 percent
E) Both a and b

Question

Quizplus · Accepted Answer

The rate of diffusion is proportional to the concentration gradient, which is the difference in concentration between the two sides of the membrane. The greater the concentration gradient, the faster the rate of diffusion. In choices A and B, the concentration gradient is 55 percent, which is greater than the concentration gradient in choices C and D, which is 5 percent. Therefore, the rate of diffusion will be fastest in choices A and B.

You Are Monitoring the Diffusion of a Molecule Across a Membrane