1. Osmosis and Diffusion!

2. IMPORTANT DEFINITIONS DIFFUSION : movement of particles from higher concentration to lower concentration DIFFUSION : movement of particles from higher concentration to lower concentration

3. DIFFUSION

4. OSMOSIS : diffusion of water across a selectively permeable membrane OSMOSIS : diffusion of water across a selectively permeable membrane In a cell, water always tries to reach an equal concentration on both sides of the membrane! In a cell, water always tries to reach an equal concentration on both sides of the membrane!

5. OSMOSIS

6. Vocabulary Terms to Know Concentration = density of particles Concentration = density of particles Permeable = allows things to pass through Permeable = allows things to pass through Selectively Permeable = allows certain things only to pass through Selectively Permeable = allows certain things only to pass through Impermeable = allows nothing to pass through Impermeable = allows nothing to pass through Solute = you add Solute = you add Solvent = added to Solvent = added to

7. During osmosis, only water diffuses across the selectively permeable membrane.

8. OSMOSIS

9. Gotta love the Greeks! ISOS=equalHYPO=underHYPER=over Remember your roots!

10. Hypotonic Solution A cell is placed in pure water A cell is placed in pure water There is a lower concentration of solutes ( dissolved substances )outside the cell than inside the cell. There is a lower concentration of solutes ( dissolved substances )outside the cell than inside the cell. Water will flow into the cell. Water will flow into the cell.

11. Isotonic Solution Equal concentrations of solutes inside and outside the cell. Equal concentrations of solutes inside and outside the cell. Water will flow into and out of the cell at equal rates (dynamic equilibrium) Water will flow into and out of the cell at equal rates (dynamic equilibrium) EX: Immunizations are isotonic solutions so they do not damage the cells by gain or loss of water. EX: Immunizations are isotonic solutions so they do not damage the cells by gain or loss of water.

12. Hypertonic Solution A cell is placed in a concentrated salt solution (seawater) A cell is placed in a concentrated salt solution (seawater) There is a higher concentration of solutes outside the cell than inside the cell. There is a higher concentration of solutes outside the cell than inside the cell. Water will flow out of the cell Water will flow out of the cell

13. Note: These are animal red blood cells. The size of the arrows indicates the magnitude and direction with which water moves.

14. What about the big boys? ENDOCYTOSIS: cells surrounds and takes in material from environment by engulfing the material! YUMMY! ENDOCYTOSIS: cells surrounds and takes in material from environment by engulfing the material! YUMMY! EXOCYTOSIS: cells expel materials from cell, such as waste or indigestible particles. GROSS! EXOCYTOSIS: cells expel materials from cell, such as waste or indigestible particles. GROSS! Both endo and exocytosis are moving large masses of material and require energy (ACTIVE TRANSPORT!) Both endo and exocytosis are moving large masses of material and require energy (ACTIVE TRANSPORT!)

15. Endocytosis

16. Exocytosis

17. ISOTONIC SOLUTIONS! Concentration of dissolved substances in solution is the same as concentration of dissolved substances inside the cell. Concentration of dissolved substances in solution is the same as concentration of dissolved substances inside the cell. Water inside cell is equal to water in solution. Water inside cell is equal to water in solution. Cells in isotonic solution do not experience osmosis and retain their normal shape. Cells in isotonic solution do not experience osmosis and retain their normal shape. EX: Immunizations are isotonic solutions so they do not damage the cells by gain or loss of water. EX: Immunizations are isotonic solutions so they do not damage the cells by gain or loss of water.

18. HYPOTONIC SOLUTIONS! Concentration of dissolved substances is lower in solution outside the cell than concentration inside the cell. Concentration of dissolved substances is lower in solution outside the cell than concentration inside the cell. There is more water outside the cell than inside. There is more water outside the cell than inside. Cells in hypotonic solutions experience osmosis in which water moves through membrane into cell. Cells in hypotonic solutions experience osmosis in which water moves through membrane into cell. EX: In animal cells, the pressure inside cell increases causing the cells to swell and sometimes burst! EX: In animal cells, the pressure inside cell increases causing the cells to swell and sometimes burst! EX: In plant cells, the rigid cell wall prevents bursting, but the cells become more firm. EX: In plant cells, the rigid cell wall prevents bursting, but the cells become more firm. CUCUMBERS IN THE MIST!

19. HYPERTONIC SOLUTIONS! Concentration of dissolved substances outside cell is higher than concentration inside cell. Concentration of dissolved substances outside cell is higher than concentration inside cell. There is more water inside cell than outside. There is more water inside cell than outside. Cells in hypertonic solutions experience osmosis in which water moves through membrane to outside of cell. Cells in hypertonic solutions experience osmosis in which water moves through membrane to outside of cell. Ex: In plant cells, membrane and cytoplasm shrink away from cell wall and plant wilts. Ex: In plant cells, membrane and cytoplasm shrink away from cell wall and plant wilts. EX: In animal cells, the pressure decreases and the cells shrivel. EX: In animal cells, the pressure decreases and the cells shrivel. Don’t be so SALTY!

20. Passive Transport: Mosey on through… Passive transport is what it sounds like! Passive transport is what it sounds like! Molecules pass through the membrane by diffusion requiring no extra energy. Molecules pass through the membrane by diffusion requiring no extra energy. The molecules just mosey on through the membrane. The molecules just mosey on through the membrane. Ex: Some of the molecules that move by passive transport are: water and lipids Ex: Some of the molecules that move by passive transport are: water and lipids

21. Passive Transport

22. Facilitated Diffusion: Help them out a bit! Remember those transport proteins in the phospholipid bilayer? Here’s where they fit in! Facilitated diffusion: passive transport across membrane with help of transport proteins. Facilitated diffusion: passive transport across membrane with help of transport proteins. Ex: Facilitated diffusion is used to move sugars and amino acids across membranes. Ex: Facilitated diffusion is used to move sugars and amino acids across membranes.

23. Facilitated Transport

24. Active Transport: ENERGY REQUIRED! Active transport is the movement of materials through a membrane across a concentration gradient. Active transport is the movement of materials through a membrane across a concentration gradient. This requires energy to counteract the movement of diffusion from high to low concentrations! This requires energy to counteract the movement of diffusion from high to low concentrations!

25. How does it work? 1) Transport protein called “carrier protein” binds with particle that is going to be transported. 2) Because of its specific shape, the carrier protein can bind to the particle and with some energy, it can move through the membrane. 3) Once the particle is released, the protein returns to its original shape. Active transport allows a particle movement into or out of a cell against a concentration gradient.

26. How carrier proteins work!

27. Active Transport

29. Cellular Transport