1. Getting In & Out of a Cell Osmosis & Diffusion Getting In & Out of a Cell Osmosis & Diffusion

2. Cell Membrane Remember Remember: The Cell Membrane is SEMI- PERMEABLE – It doesn’t let EVERYTHING inside the cell Cells do this to maintain homeostasis – Stable internal environment Remember Remember: The Cell Membrane is SEMI- PERMEABLE – It doesn’t let EVERYTHING inside the cell Cells do this to maintain homeostasis – Stable internal environment

3. PASSIVE TRANSPORT Substances that cross the cell membrane without taking energy from the cell

4. DIFFUSION The movement of molecules from an area of high concentration to low concentration – Concentration gradient = difference in concentration! equilibrium Eventually this leads to equilibrium – Equal concentration throughout space The movement of molecules from an area of high concentration to low concentration – Concentration gradient = difference in concentration! equilibrium Eventually this leads to equilibrium – Equal concentration throughout space

5. O HH O H H O H H O H H O HH O HH O HH O H H O H H O HH O HH O H H O HH O Sugar Molecules

6. O HH O H H O H H O H H O HH O HH O HH O H H O H H O HH O HH O H H O HH O H H

7. O HH O H H O H H O H H O HH O HH O HH O H H O H H O HH O HH O H H O HH O HH

8. O HH O H H O H H O H H O HH O HH O HH O H H O H H O HH O HH O H H O HH O H H O HH O H H

9. OSMOSIS Process of WATER diffusing across a cell membrane from an area of higher concentration to an area of lower concentration

10. Directions of Osmosis The net direction of osmosis depends on the concentration of solutes outside & inside the cell – Hypotonic – Hypertonic – Isotonic The net direction of osmosis depends on the concentration of solutes outside & inside the cell – Hypotonic – Hypertonic – Isotonic

11. HYPOTONIC Concentration of molecules are lower on OUTSIDE of cell Water Water diffuses INTO the cell

12. HYPERTONIC Concentration of molecules are lower on the INSIDE of the cell WATER WATER diffuses OUT of the cell Concentration of molecules are lower on the INSIDE of the cell WATER WATER diffuses OUT of the cell

13. ISOTONIC Concentration of molecules is equal inside & outside the cell – At equilibrium Water diffuses equally into and out of the cell – No NET movement of water

14. Examples

15. FACILITATED DIFFUSION ION CHANNELS – FACILITATED DIFFUSION Membrane proteins Membrane proteins that allow ions to enter the cell Ions must go through channels because they can’t dissolve through lipid bilayer Membrane proteins Membrane proteins that allow ions to enter the cell Ions must go through channels because they can’t dissolve through lipid bilayer

16. ACTIVE TRANSPORT Movement of materials against the concentration gradient Requires energy Called “pumps”

17. ENDOCYTOSIS Process of cells ingesting external fluid, macromolecules, other cells, etc. Cells do this for substances that are too BIG to pass through the cell membrane Process of cells ingesting external fluid, macromolecules, other cells, etc. Cells do this for substances that are too BIG to pass through the cell membrane

18. ENDOCYTOSIS CONT… External materials are enclosed in a membrane- bound organelle called a VESICLE These can fuse with lysosomes to be digested

19. PINOCYTOSIS & PHAGOCYTOSIS Pinocytosis – Solutes or fluid Phagocytosis – Large particles or whole cells Pinocytosis – Solutes or fluid Phagocytosis – Large particles or whole cells

20. EXOCYTOSIS Vesicles in the cell fuse with the cell membrane and release the contents

21. EXAMPLES