For each of the following atoms or molecules, determine whether they will cross a plasma membrane (if following their concentration gradient) by simple diffusion or by facilitated diffusion. Then, briefly explain your reasoning.
O2 (oxygen gas) crosses the plasma membrane by ______________________ diffusion,
because ________________________________________________________________
Glucose crosses the plasma membrane by ______________________ diffusion,
because ________________________________________________________________
Water crosses the plasma membrane by ______________________ diffusion,
because ________________________________________________________________
Na+ (sodium ion) crosses the plasma membrane by ______________________diffusion,
because _________________________________________________________________
Cholesterol crosses the plasma membrane by ______________________ diffusion,
because _________________________________________________________________
Which of these atoms or molecules require facilitated diffusion to cross a plasma membrane, but are able to simply diffuse across a dialysis tubing membrane?
?