The Living World 6th Edition by George Johnson, Jonathan Losos,William Ober,Claire Garrison

Exercise 15

Figure 5.33 In the lungs, there are steep concentration gradients for oxygen and carbon dioxide molecules such that large numbers of these molecules move across the plasma membrane of the cells that line the lungs. These molecules pass through the plasma membranes by simple diffusion. This process is fast and efficient. Would this process be just as efficient if the oxygen and carbon dioxide molecules passed through the membranes by facilitated diffusion Why or why not