What is the best reason why oxygen (O₂)can cross the plasma membrane by simple diffusion,but glucose must be transported across the barrier by facilitated diffusion?
A)Oxygen is a much smaller molecule,making it easier to pass through the molecules of the plasma membrane.
B)Oxygen is a nonpolar molecule,easily passing through the nonpolar middle area of the plasma membrane.
C)Oxygen can be burned/consumed as it crosses the membrane,providing the energy needed for its passage.
D)Glucose is nonpolar,making it very difficult for it to cross the polar portions of the plasma membrane structure.

Question

Quizplus · Accepted Answer

Oxygen is a much smaller molecule than glucose, which makes its movement across the plasma membrane by simple diffusion much easier. Size plays a crucial role in determining the ability of the molecule to cross the membrane. The smaller the molecule, the easier it is for it to pass through the molecules of the plasma membrane.

What Is the Best Reason Why Oxygen (O₂)can Cross the Plasma