1. Chapter 5 Membrane Dynamics

2. Outline  Cell Membranes  Movement across membranes  Distribution of water and solutes in the body  Osmosis Lab

4. Proteins: role in communication

5. Proteins act as “passageways”  Channel Proteins Open Gated*  Carrier Proteins

6. Open and Gated Channels Normally closed Normally open

7. These are types of “gates”  Chemical gates  Voltage gates  Mechanical gates Gated channels almost always closed

8. Cystic Fibrosis Trans-membrane Receptor CFTR mutation Blocks Cl- CF: autosomal recessive

9. Carrier Proteins Like a revolving door!

10. Movement across membranes  I. Passive transport: no ATP Non-carrier mediated Carrier mediated

11. Diffusion: passive Without membraneAcross membrane: no carrier Passive transport Passive diffusion

12. Passive movement can require a carrier Specific Can saturate

13. II. Active Transport  Active Transport Requires a TRANSPORTER AND Requires ENERGY

14. Primary Active Transport Is this a symport or antiport?

15. Let’s look at both primary and secondary together!

16. Figure 5-28 (insert) Na+ gradient is potential energy NOTICE

17. Distribution of water and solutes in the body

18. Osmosis  Movement of water across a semi-permeable membrane

19. Compare osmolarity of one solution to another solution.  Isosmotic  Hyperosmotic  Hyposmotic

20. Number of particles are A B A Particle # B Particle # Term Used 300 A & B are Isomotic #>300300 A Hyperosmotic to B #<300300A Hyposmotic to B AB

21. Now, look at the following terms  Isotonic  Hypotonic  Hypertonic

22. Tonicity defines what a solution would do to the cell volume (size).

23. To cell size and tonicity: You must understand the terms  Non-penetrating versus Penetrating solutes But I’m so tired…

24. 3 Beakers with various concentrations of non- penetrating solutes and RBCs Here’s your experiment: You place red blood cells in the three Beakers and view them later under the microscope. Now what will you observe? 200 mOsm600 mOsm300 mOsm

25. Tonicity defines the affect on cell size or shape. Crenation SwellingNo change Hypertonic IsotonicHypotonic 600 mOsm 300 mOsm200 mOsm Non Penetrating

26. What if…  A cell of 6 Osm is placed in a solution also of 6 Osm then what is the tonicity? Oops, that’s tricky! There is no way to know the tonicity with the information given! Why??

27. But what eventually happens to H 2 0? Look and penetrating versus non-penetrating

28. Clinical Application  A. 0.9% saline SMC P hysio 0.9% saline is non penetrating= 300 mOsm A. 0.9% saline: is isosmotic and isotonic

29. Transport of Macromolecules

30.  White blood cells Phagocytosis  Receptor-Mediated Endocytosis  all cells can carry out endocytosis  Transport errors…

33. Membrane Potential Cell charge and cell function are related

34. The cell membrane separates charges

35. Measurement of this charge What ions may cause this charge?

36. Nernst Equation: You can calculate this answer.  E ion = 61/z log [ion] out /[ion] in  61 is a constant  Z is charge of ion IonK+ mM Na+ mM ICF15015 ECF5150

37. Now let’s now integrate the concept of cell membranes and a physiological process…

38. Cell function and Charge