Question 1: Do most polar molecules freely cross the lipid cells membrane? Name two groups of polar molecules.
Question 2: What is the name for the special case of diffusion that involves the movement of water molecules across a membrane?
Question 3: Why is a molecule of urea unable to diffuse across the membrane?
Question 4: How does a urea molecule interact with water molecules? Why?
Question 5: Why is there now a net movement of water molecules? Which direction do they move?
Questtion 6: What happens to the water level on the side of the beaker why the water molecules are moving into?