Diffusion + Dynamic Equilibrium

What is diffusion?

Does simple diffusion require energy?

Molecules diffuse from areas of ______ concentration to ______ concentration.

What does dynamic equilibrium mean?

If two compartments reach equilibrium, does movement stop completely?

Why does O2 diffuse across the membrane more easily than Na+?

What kind of molecules pass through the phospholipid bilayer most easily?

Why do ions have trouble crossing the membrane?

What is the difference between concentration and gradient?

What would happen to diffusion if the concentration difference became larger?