1. Ch 7.2 Plasma Membrane Yesterday we talked about things all cells have. One of those things was the plasma membrane. Can you remember the other two? Lets review from yesterday

2. 9/6/12 Warm-up 1. What are the three principles of the cell theory? 2. What are three things that all cells have in common?

3. Think-Pair-Share On a sheet of paper, work with your table partner to come up with three characteristics AND one example for prokaryotic cells and eukaryotic cells.

4. Prokaryote Eukaryote contains nucleus contains organelles (membrane-bound structures within cell) mostly multicellular critters Two Basic Cell Types no nucleus no organelles mostly unicellular critters very small in size ex. bacteria, archaebacteria ex. plants, animals, yeast ALL cells have 1. plasma membrane 2. cytoplasm 3. genetic material

5. Plasma Membrane- a boundary that controls what leaves and enters the cell. Why is it important to control what leaves and enters the cell???

6. All prokaryotes and eukaryotes have a plasma membrane. It surrounds the cell, providing protection and support. It helps a cell maintain homeostasis, by regulating what enters and leaves the cell. It is selectively permeable: Only allows certain materials through.

7. The plasma membrane has 4 main components. 1.Phospholipid Bilayer 2.Transport proteins 3. Cholesterols 4.Carbohydrates

8. Structure of the Plasma Membrane The plasma membrane is composed of a phospholipid bilayer – two layers of phospholipids are arranged tail to tail.

9. Phospholipids – make up the lipid bilayer: a. Polar, hydrophilic heads (water loving) b. Nonpolar, hydrophobic tails (water fearing)

10. Hydrophilic = Water Loving Hydrophobic = Water Fearing

11. Other Components of the Plasma Membrane Within the Phospholipids there are 3 other things. Transport proteins Cholesterols Carbohydrates

12. Other Components of the Plasma Membrane Transport proteins - create tunnels through which certain substances enter and leave the cell.

13. Other Components of the Plasma Membrane Cholesterols contribute to the fluidity of the plasma membrane in that they prevent the fatty-acid tails from sticking together.

14. Other Components of the Plasma Membrane Cholesterols contribute to the fluidity of the plasma membrane in that they prevent the fatty-acid tails from sticking together.

15. It looks like this

16. Fluid Mosaic Model http://www.susanahalpine.com/anim/Life/me mb.htm http://www.susanahalpine.com/anim/Life/me mb.htm The components of the plasma membrane are in constant motion sliding past each other. The phospholipids in the bilayer create a “sea” in which other molecules can float, hence “fluid” and “mosaic” because there are many components which appear as a pattern or a mosaic.

17. Ok……what??? Fluid mosaic model - All the parts of the plasma membrane are moving all the time

18. Review/Study Questions How does the plasma membrane help maintain homeostasis? What does it mean if something is selectively permeable? What makes up the plasma membrane? Why are the phospholipids arranged like they are?

19. Plasma Membrane Poster On your BLANK PAPER complete the following: 1. Title: Plasma Membrane 2. Draw a plasma membrane in color (page 188!)) 3. Label the: * Phospholipids * Proteins * Carbohydrates * Cholestrols * Inside the cell * Hydrophobic areas in BLUE (water fearing!) * Hydrophilic areas in RED (water loving) 4. In the lower RIGHT corner, write your name

20. Questions on Back – Define plasma membrane – What is the plasma membranes function? – Tell me what the cholesterol does – Tell me what the transport protein does – Tell me what the carbohydrate does