1. a selectively permeable phospholipid bilayer that surrounds all cells. The Cell membrane is …

2. Selectively Permeable It chooses or selects specific substances Permeable means to pass pass through A selectively permeable membrane is selective about what it allow to pass through

3. Cell membrane diagram Inside cell Outside cell Cell membrane

4. Polarity Polar: has opposite charges at opposite ends of molecule * Example: Water Non-polar: Balanced molecule with charges evenly spaced around molecule * Example: fats and oils

5. Phospholipid diagrams

7. Outside cell Inside cell A picture of the cell membrane using a transmission election microscope T.E.M.

8. Membrane proteins are imbedded in plasma membrane. Outside cell Inside cell nucleus

9. Organelles are surrounded by membranes! Golgi Apparatus Lysosomes Mitochondria

10. Membrane proteins do the following 4 things 1)Recognition proteins: Identify the cell! (recognize the cell) 2)Receptor proteins: React to stimulation and cause cell to function (react). 3)Transport Proteins: transport substances across plasma membrane. 4)Enzymes: Catalyze reactions on membrane surface

11. Recognition Proteins

12. Passive Transport Not requiring energy or ATP When substances diffuse from a high to a low concentration When they diffuse down their concentration gradient

13. Types of Transport Proteins

14. Facilitated Diffusion: a passive form of transport using membrane proteins Before After

15. Active Transport Requires Energy or ATP When something large or difficult needs to pass through the membrane When substances have to be pushed or “pumped” backwards from a low to a high concentration. Proteins that do this are called protein pumps

16. Active transport Adapted from Campbell, Reece & Mitchell, Biology 6 th edition, 2002 with permission of Pearson Education, Inc. 1 2

17. Active transport (cont.) Adapted from Campbell, Reece & Mitchell, Biology 6 th edition, 2002 with permission of Pearson Education, Inc. 3 4

18. Active transport (cont.) Adapted from Campbell, Reece & Mitchell, Biology 6 th edition, 2002 with permission of Pearson Education, Inc. 56

19. Endocytosis: when the cell membrane must move to engulf larger substances that cannot fit through There are 3 different types that will be discussed

20. Phagocytosis: when very large substances are engulfed into the cell. (pac-man)

21. Pinocytosis Same as phagocytosis but with smaller substances and liquids “cell slurping”

22. Exocytosis When substances leave the cell (saliva, sweat, oils, digestive juices, tears)

23. The same cell is a hypertonic environment will loose water, shrivel, and probably die. A cell in a hypotonic solution will gain water, swell, and burst. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 8.12