3.11_Diffusion and Osmosis
1. A membrane that allows all molecules in the solution to pass through is called what type of
membrane?
2. A membrane that allows some molecules in the solution, but not others, to pass through is called
what type of membrane?
3. A membrane that does not allow any molecules in the solution to pass through is called what type
of membrane?
4. Look at the diagram below. Describe what will happen over time. Sketch the situation at a much
later time after equilibrium has been reached.
5. Consider the container below which has two separate compartments separated by a permeable
membrane. Describe what will happen over time. Sketch the situation at a much later time. What
will be the concentrations of salt and sugar on each half of the container?
6. What is the percentage of water in each half at the beginning?
7. What is the percentage of water in each half at the end?
8. Did the water move across the membrane? Which direction.
9. Consider the drawing. What will happen over time?
10. Consider the drawing. The membrane is permeable to salt and water, but not to sugar.
a. What is this type of membrane called?
b. In what direction will the salt move?
c. In what direction with the sugar move?
d. In what direction will the water move?
e. In which compartment will the water rise?
11. Label the three images below as isotonic/ hypertonic/ hypotonic (with regard to the solution the
cell is placed in)
12. Movement across the cell membrane that does not require energy is called
[active / passive] transport.
13. The difference in the concentration of a substance across a space is called a concentration
[equilibrium / gradient].
14. If there is a concentration gradient, substances will move from an area of high concentration to an
area of [equal / low] concentration.
15. The cell membrane is [selectively permeable / impermeable].
16. [Equilibrium / Diffusion] is the simplest type of passive transport.
17. The diffusion of water through a selectively permeable membrane is called [osmosis / diffusion].
18. The direction of water movement across the cell membrane depends on the concentration of free
water [molecules / solutions].
19. A solution that causes a cell to swell is called a [hypertonic / hypotonic] solution.
20. Organelles that collect excess water inside the cell and force water out are called
[diffusion organelles / contractile vacuoles]
21. The process of taking material into the cell by infolding the cell membrane is called
[endocytosis / exocytosis]
22. In [facilitated / molecular] diffusion, membrane proteins help molecules across the membrane.
23. In diffusion, molecules [spread out / condense]
24. The lipid bilayer describes [a type of transport / the cell membrane]
25. Facilitated diffusion moves substances down their concentration gradient [with / without] using
the cell's energy.
26. What are the parts of a solution?
27. Label a cell membrane (bilayer, proteins)
28. Explain what will happen to cells when placed in isotonic, hypertonic, and hypotonic solutions.
29. Definition the following:
Diffusion Equilibrium Osmosis Isotonic Hypertonic Hypotonic Facilitated diffusion Endocytosis Phagocytosis Pinocytosis Exocytosis 30. Explain what happens when you place a bag full of starch (solution) into a solution of iodine.