1. Exploring the Cellular Basis of Life

7. Cells are small

8. Small cells are more efficient Surface area to volume ratio must remain high

10. Features Common to All Cells

12. Prokaryotic Cell

27. Crossing the Membrane Cell Membrane Structure and Transport

29. Fluid Mosaic Model of Membranes

30. Membrane Proteins

31. Membrane Fluidity

34. The diffusion of water molecules through a selectively permeable membrane Osmosis will continue as long as there are more water molecules on one side of the membrane (“osmotic pressure”) Water will continue to diffuse until there are equal numbers of molecules inside and outside the cell (“osmotic balance”) Osmosis

35. 60% H 2 O 90% H 2 O

36. Water will move out of to the left across the membrane until osmotic balance has been reached

37. 100% H 2 O 80% H 2 O

38. 90% H 2 O 90% H 2 O

39. 75% H 2 O 90% H 2 O Water leaves the cell and it shrinks. This is called plasmolysis in plant cells