1. Transport through the Cell Membrane

3. The Cell Membrane is Semi-permeable SOME MOLECULES CAN GET THROUGH Very small or Non-charged (nonpolar)

4. Passive Transport Does not expend cellular energy for the movement to take place Ex-rolling down a hill

5. 3 types: 1.Diffusion 2.Osmosis 3.Facilitated Diffusion

6. I. DIFFUSION: Definition: Transport of molecules (in general) From an area of higher concentration to an area of lower concentration Until equal distribution of concentrations reached in all areas (EQUILIBRIUM) Due to the random movement of molecules

7. Conceptual Diagram:

9. Example: If you had glucose molecules and starch molecules, which ones do you think could get through after 24 hours and why? The membrane is permeable to both. 4% C 6 H 12 O 6 in H 2 O 15% NaCl 2% C 6 H 12 O 6 15 % NaCl 2% C 6 H 12 O 6 30% NaCl in H 2 O

10. Definitions Solute: what gets dissolved Solvent: What does the dissolving, more plentiful that solute Solution: the mixture of solutes and solvent Example: H 2 O and NaCl Solute: NaCl Solvent: H 2 O Solution: H 2 O and NaCl

12. II.OSMOSIS: Definition: Diffusion (movement) of H 2 O from to high to low concentration THROUGH A MEMBRANE until equilibrium

13. II.OSMOSIS:

17. How do you get different concentrations of water (2 ways)? **FIX IN YOUR NOTE TEMPLATE 1.Change the amount of solute or solvent. 2.Add a membrane

18. 3 Types of Solutions (outside of cell): 1.Hypertonic 2.Hypotonic 3.Isotonic

19. 1.Hypertonic: MORE More solute, less solvent (H 2 O) 90% water 80% water

21. 2. Hypotonic: LESS Less solute, more solvent

22. 3. Isotonic: EQUAL Equal amounts of solute/solvent concentrations on both sides of membrane

24. Consequences: Hypertonic  PLASMOLYSIS (cell shrinking) Examples: Drinking out of ocean when you are dying of thirst or Placing a fresh water fish in salt water… 

26. Hypotonic  Cytolysis (cell bursting) Examples: Place a salt water fish in fresh water  Red Blood Cells in pure water

27. Turgor Pressure = Osmotic Pressure As a result of osmosis, extra water molecules accumulate on one side of membrane and cause pressure on the membrane  “Turgor” Example: water

28. III. FACILITATIVE DIFFUSION: Protein Channels in the cell membrane accept only specific particles, like a lock accepts a particular key.

29. III. FACILITATIVE DIFFUSION:

30. Many of these protein channels are “two-way” and are called PORES. These transport molecules ions or molecules (solutes) through membranes in either direction

31. III. FACILITATIVE DIFFUSION: Like an open door allows you to pass into or out of a room. Different solute particles fit different pores This depends on Size Polarity Shape of molecule Ex. Glucose

32. III. FACILITATIVE DIFFUSION: When a solute that is plentiful on one side of membrane, they will pass by diffusion toward other side with the lower concentration. Until concentration becomes equal on both sides

33. DON’T FORGET, THESE WERE ALL PASSIVE TRANSPORT – SO THE CELL DID NOT NEED TO EXPEND ANY NRG TO MAKE IT HAPPEN!!!!!