1. “Materials move across the cell’s membranes”
Section 2.3

2. Do Now What is the purpose of the cell membrane in a cell?
What goes in and out of our cells?
Why are our membranes important?

3. Objectives
To explain the different functions of the macromolecules in the plasma membrane.
To understand the process of diffusion.
To compare and contrast active and passive transport.

4. Membranes
“Fluid Mosaic Model”

5. Membrane Components Phospholipids:
Gives the general structure of the membrane

6. Membrane Components
Proteins: allow bigger substances to pass through, also provide structure

7. Membrane Components
Cholesterol: helps maintain structure of phospholipids, prevents them from sticking

8. Membrane Components
Carbohydrates: receptors that send and receive signals.

9. Simulation Activity
Everybody Stand up!!! Lets make a membrane out of the desks.
I need 4 volunteers (1-H2O, 3-Glucose)

10. Types of Transport Passive Transport Active Transport
Vesicular Transport

11. Passive Transport Do NOT require energy
Go from an area of high concentration to an area of low concentration
“Go with the flow”

12. 3 Types of Passive Transport
Diffusion
Facilitated Diffusion
Osmosis

13. Diffusion
Molecules move from a high concentration to a low concentration to create DYNAMIC EQUILIBRIUM.

14. Effected By… Heat- higher temp increases rate State of Matter
Solid- slow
Liquid- faster
Gas- fastest
Size and Concentration
Bigger= slower
More concentration = faster

15. Perfume Demo
Before
After

16. Food Coloring Demo
Before
After

17. Facilitated Diffusion
the molecules need a “helper” or “facilitator” to allow them to cross the membrane when they are too big.

18. Do NOW What is passive transport?
What are 2 examples of passive transport?
Explain what happens when you put a sugar cube in your tea in regards to diffusion.

19. Objectives To understand how the process of Osmosis works.
To explain the different types of solutions
To compare and contrast endocytosis vs. exocytosis.

20. Osmosis
The flow of WATER from a high concentration to a low concentration
Occurs based on the types of solutions you are working with.

21. Solution
A) a mixture in which you cannot separate the components (ex: Kool aid)
i. solute: the substance being dissolved
Ex: kool aid powder
Ii. solvent: The substance doing the dissolving
Ex: water

22. Solutions
Solutions can be…
Isotonic
Hypertonic
hypotonic

23. Isotonic Solutions
Same amount of solute inside the membrane as there is outside.
Cell in this solution: NOTHING 
Plant Cell
Blood Cell
11,397x

24. HYPERtonic Solutions More solute, less solvent
Cell in this solution:shrinks/shrivels 
“Plasmolysis”
“Crenates”

25. HYPOtonic Solutions Less solute, more solvent
Effect: cell swells or bursts! /

26. High or low Solute? Cell in ________ Solution

27. A salt water fish is put into a freshwater aquarium.
Scenario 1
A salt water fish is put into a freshwater aquarium.
What type of solution is the freshwater?
What is going to happen to the cells of the fish?

28. Scenario 2
A patient is given an IV, which contains the perfect balance of glucose
What type of solution is in the IV?
What is going to happen to the cells of the human?

29. Scenario 3
Your garden is infested with slugs so you go around pouring salt on them
What type of solution is this salt?
What is going to happen to the cells of the slug? (don’t do this to the poor slugs )

30. Practice
By yourself or with a partner (anyone), work on the diffusion problems.
First try to do this by yourself, then verify your answers with a partner. Try to help each other. If you are confused, raise your hand and I will come help you!!
If you finish early, try to answer the “Think about it” questions on my desk! If you don’t finish, please finish it for homework.