1. Cell Boundaries
Biology
Ms. Lew

2. Vocabulary Hypertonic Active Transport Hypotonic Diffusion Isotonic
Osmosis
Phagocytosis
Phospholipid
Pinocytosis
Semipermeable
Active Transport
Diffusion
Endocytosis
Exocytosis
Facilitated Diffusion
Hydrophilic
Hydrophobic

3. to regulate movement of molecules into/out of a cell
Cell Membranes
One of the most important functions of a cell membrane:
to regulate movement of molecules into/out of a cell

4. A cell membrane is said to be
__________________________
Which means only specific kinds of molecules can get through the membrane
Another word for it is ______________________
Selectively Permeable
Semipermeable

9. Label the diagram of a cell membrane shown below:
Outside
of cell
Carbohydrate
chains
Proteins
Cell
membrane
Inside
of cell
(cytoplasm)
Protein
channel
Lipid bilayer

10. 3. Selectively Permeable
Cell membranes let some molecules enter a cell, but prevents other molecules from getting in.
Can Enter Can Not Enter
- Water
- Small Molecules (O2 & CO2)
- Non-polar lipids
- Macromolecules
- Ions (Na+,Cl-)
- Hydrophilic molecules (glucose)

11. The more solute per volume equals a greater concentration.
The concentration of a solution is:
The mass of the SOLUTE divided by the volume of the SOLUTION
For example: 10g/1L
The more solute per volume equals a greater concentration.

12. 6. Diffusion
The movement of molecules from an area of high concentration to an area of lower concentration
Spray and food color demo

13. Example of Diffusion: Beaker of water. Add salt to the water.
Will all of the water be salty or just the side of the beaker that you dumped the salt into?
When you add salt the salt will diffuse to all of the water.

14. Figure 7-15 Osmosis

15. Figure 7-15 Osmosis

16. Example of Diffusion: The smell of popcorn after it’s been popped.
Does the smell of popcorn stay where the popcorn was popped? Why or why not?

17. Diffusion

18. Osmosis
The diffusion of water. The movement of water from a high water concentration to a low water concentration.

19. Osmosis

20. 3 types of solutions
- Hypertonic
- Hypotonic
- Isotonic

21. Hypertonic
Solution has a higher solute concentration than the cell. There’s more water concentration inside cell…
SO,
- Water leaves the cell
- Animal cells shrink

22. Hypotonic
Solution has a lower solute concentration than the cell. There’s more water concentration outside the cell…
SO,
Water enters the cell
Animal cells expand and possibly burst

23. c. Isotonic
The concentration of the solutes is the same inside and outside the cell.
Water goes in and out at the same rate and pressure doesn’t change

24. Types of Diffusion
across a membrane

25. Facilitated Diffusion
The movement of specific molecules across cell membranes through protein channels.

26. Facilitated Diffusion

27. Active Transport
Energy requiring process that moves material across a cell membrane against a concentration difference.

28. Active Transport

29. Facilitated diffusion
20. Complete the following chart to compare types of movement through a cell membrane:
Types of molecules transported
Special channel required?
Energy reguired?
Diffusion
Osmosis
Facilitated diffusion
Active transport no no
Small molecules
water no no
ions, sugars (glucose), salts
yes no
ions (H+, K+, Na+, Ca2+)
yes
yes

30. Overview

31. Movement of materials
to/from membrane

32. Endocytosis: Taking material in to the cell through cell membrane pockets
ie. Phagocytosis: Solids or large molecules moved
ie. Pinocytosis: Liquids moved

33. Exocytosis: Releasing material from the cell