1. Catalyst 1. What are the 3 parts of the Cell Theory? The smallest…
All life is made…
All cells come…
2. What is the function of the:
Cell membrane
Ribosomes
Cytoplasm

2. Cell Membrane Part 1

3. Today’s Objectives
SWBAT explain the purpose of the plasma membrane and selective permeability. SWBAT describe the structure of a phospholipid. SWBAT explain how the arrangement of phospholipids lead to the formation of a lipid bilayer SWBAT identify the various components of the plasma membrane

4. Agenda Coffee Filter Intro Iodine bag set up Plasma Membrane Lecture
Oil/Water demo during notes
HW: plasma membrane coloring
copyright cmassengale

5. Homeostasis Balanced internal condition of cells
The Plasma Membrane
5/23/2018
Homeostasis
Balanced internal condition of cells
Also called equilibrium
Maintained by plasma or cell membrane controlling what enters & leaves the cell
G. Podgorski, Biol. 1010

6. Why do houses need walls?
Protect it from the environment
Decide what can come in and go out

7. Coffee Filter Demo

8. Plasma Membrane
The plasma membrane is the flexible outer layer of cells.
(inside of cell wall if present)
Has three main jobs:
Separate cells from the outside
Protect cells from the environment
Decides what can enter (or exit) the cell

9. Selective permeability: the ability that allows some molecules to pass into the cell while keeping others out

10. >> Check for Understanding
How does a window screen show selective permeability?

11. What are membranes made of?
Membranes are made up of molecules called phospholipids.
Phosphate and glycerol

12. What are membranes made of?
 Mixes w/ water
“HATES” water 

13. What are membranes made of?
To keep their non-polar tails away from water, phospholipids form a two-sided layer called a bilayer.
Water
No Water
Water

14. Cell Membrane Polar heads are hydrophilic “water loving”
The Plasma Membrane
5/23/2018
Polar heads are hydrophilic “water loving”
Nonpolar tails are hydrophobic “water fearing”
Makes membrane “Selective” in what crosses
G. Podgorski, Biol. 1010

15. Cell Membrane Part 2

17. What are membranes made of?

18. Guided Practice: A-B-C-D Cards
For each question, hold up the card for whatever letter you think is correct

19. Question 1
What term means that membranes are made up of two back-to-back layers? a) selective permeability b) non-polar tails c) bilayer d) phophate

20. Question 2
Which part of the diagram below is polar? a) A b) B c) Both A and B d) Neither A nor B A B

21. Question 3
Which part of the diagram below would not mix well with water? a) A b) B c) Both A and B d) Neither A nor B A B

22. Question 4
Which part below will end up in the middle of a bilayer? a) A b) B c) Both A and B d) Neither A nor B A B

23. Question 5
In what types of organisms are cell membranes found? a) prokaryotes b) eukaryotes c) bacteria d) all of the above

24. Question 6
Which of the following are components of a phospholipid? (hold up all that apply) a) fatty acids b) glycerol c) monosaccharides d) phosphate

25. Oil and Water Demo What kinds of items do you think will pass through?
For the items that can’t pass through, what can we do to help them get through?

26. Think and answer on your notes
1. In your own words, explain how a pasta strainer shows “selective permeability.” How is this similar to cell membranes? 2. Why do phospholipids form bilayers? 3. How does the oil and water demo relate to the cell membrane?

27. Other Membrane Components
Turns out that the cell membrane is NOT this simple: X

28. Play video Mrs. G

29. Other Membrane Components
There are other parts to the membrane, including cholesterol, proteins, and carbohydrates

30. Cholesterol: Holding it Together
Cholesterol is mixed in with the phospholipids to keep the tails from sticking together. This gives the cells more stability

31. Transport Proteins: The Doors to the Cell
Some molecules have trouble crossing the membrane… Why??? Transport proteins help molecules enter or exit the cell.

33. Other Parts: Sending Signals
Other proteins and carbohydrates stick out from the cell; they act as signals for other cells to read.

34. The Fluid Mosaic Model
The parts of the cell membrane are not held in place; they flow around the cell like boats in water. This is called the fluid mosaic model.

35. Exit Ticket

36. Plasma Membrane Worksheet/Coloring
Homework
Plasma Membrane Worksheet/Coloring