1. Warm Up Last week, we compared the cell to a complex factory.
Why is it important for factories to get deliveries?
How do you think the cell gets “deliveries”?

2. Cell Membrane Gatekeeper Regulates what comes in and out of the cell
Main components: proteins and phospholipids
The cell membrane is selectively permeable
Allows some things through without energy, but not everything

3. Cell Wall Found only in plant cells and bacteria cells
Main function is support

4. Diffusion
The movement of molecules from an area of high concentration to an area of low concentration
Molecules tend to “spread out”
Requires no energy

5. Equilibrium
When molecules are evenly spread throughout a space

6. Osmosis The diffusion of water across a semipermeable membrane.
Water will travel to where there is a lower concentration
If you add something like salt to the solution…

7. Rule for Osmosis:
Water will get sucked to wherever there is a higher concentration of salt.
The following slides illustrate what direction water travels if a cell is placed in different solutions.

8. Why is Osmosis Important?
Osmosis is important to cell functions.
Red blood cells use osmosis to carry nutrients from plasma in the cell and wastes out of the cell.

9. Effect on living cells
Animal
Plant

10. Hypertonic Cells
There is a higher concentration of salt outside of the cell so water moves out of the cell
Why is it dangerous to drink sea water?

11. Cells In Different Solutions
Isotonic cells= There is an equal amount of salt inside and outside of the cell, so water stays in balance and cell is at equilibrium.

12. Hypotonic = less
There is a higher concentration of salt inside of the cell so water rushes into the cell.

13. Warm Up
What will happen to a houseplant if you water it with salt water (a hypertonic solution)?
True or False: Diffusion happens naturally when particles go from a lower concentration to an area of higher concentration. (Think about food coloring in water)

14. Passive Transport
The movement of substances across a cell membrane without the use of energy by the cell. Used for transporting small particles
Examples Diffusion & Osmosis

15. Active Transport
Cell uses energy to move things in and out. Example: food molecules
Cell membrane actually opens and closes.
Active Transport Video

16. Check for understanding
The prefix exo- means “out of” and the prefix endo- means “taking in”. How do these meanings relate to the meaning of exocytosis and endocytosis?

17. Exocytosis & Endocytosis
Exocytosis: large molecules “exit” the cell.
Ex: Waste products
Endocytosis larger substances “enter” the cell.
Ex: Food molecules

18. Two Types of Endocytosis
Pinocytosis: the cell takes in liquid substances
Phagocytosis- the cell takes in food particles “phood” (food)

19. Check for understanding #2

20. Endocytosis/Exocytosis
Taking “in” or letting “out” large molecules by the cell
Phagocytosis = “phood”, taking in food particles
Pinocytosis = liquid substances

21. Organelles and functions
Difference between animal and plant cells
What organelles look like

22. Exit Slip Create three scenarios in which osmosis would make water
1.Come into the cell
2. Leave the cell
3. Stay isotonic and balanced
Draw a sketch of what the resulting cell would look like