Cells have external and internal “membranes”

1. Lecture 10 - Membranes Cells have external and internal “membranes”

2. Adjacent cells are separated by a fluid filled space Intercellular fluid space Cell #2 Cell membrane Cell #1 Cell membrane

3. Hydrophilic head Constant motion Hydrophobic tails Phospholipids

4. Air Hydrophobic tail Hydrophilic head Water

5. Hydrophilic Hydrophobic Phospholipid bilayer Hydrophobic Hydrophilic

6. The lipid bilayer is called “fluid” because the phospholipds are in continuous motion laterally Lateral movement only Time Fig. 5.04

7. Cell – watery environment “oily” membrane External – watery environment

8. Water Phospholipid Bi-layer Water liposome

9. Liposome delivers anticancer drug to tumor Ovarian tumor

10. Phospholipid bi-layers have proteins

11. Extracellular fluid Phospholipid tails Make him STOP!! Cytosol Proteins Fig. 5.07a

12. Phospholipid bi-layers have cholesterol

13. Glycoprotein = protein + carbohydrate

14. HIV Glycoproteins 1. HIV match up with human cells 2. Communication between cells

15. Binding of HIV glycoproteins and proteins of cell

16. 100,000,000,000 cells at birth Glycoproteins establish brain cell connections Every cell connected to 10,000 other cells 1015connections at birth 10,000,000,000,000,000 (quadrillion)

17. Movement of molecules and ions in and out of cells

18. Brownian Motion Random motion of ions, atoms, molecules due to their kinetic (motion) energy.

19. Brownian motion results in molecules becoming evenly spread out

20. Dust Air molecules keep dust suspended because air molecules are in constant motion (Brownian motion)

21. Diffusion Defined Movement of substance from a region of higher concentration of substance to region of lower concentration of same substance.

22. Diffusion

23. A couple of drops of dye Diffusion begins Dye is evenly distributed

24. Osmosis defined Diffusion of solvent (water) across a permeable membrane.

25. Membrane Osmosis

26. Kidney receives 20% of blood flow and cleans blood by osmosis and diffusion

27. Kidney machine performs blood cleansing by diffusion of waste and toxins

28. Hypotonic (outside of cell) 10% solute 90% water outside cell Goes in fast Goes out slow 30% solute 70% water Hypotonic = Cell fills up with water Inside cell

29. Hypertonic (outside of cell) 30% solute 70% water outside cell Goes in slow Hypertonic = Cell loses water and shrinks (plasmolysis) 10% solute 90% water Inside cell Goes out fast

30. Isotonic (outside of cell) 30% solute 70% water outside cell Isotonic = Cell gains and loses equal water – stays same size 30% solute 70% water Inside cell

32. Hypertonic Isotonic Hypotonic

33. Plasmolysis cell shrinkage Cell Wall Plasma membrane shrinks away from cell wall when cell loses water.

34. Facilitated Diffusion Diffusion of ions or molecules across membrane using membrane carrier protein

35. Membrane Protein Facilitated Diffusion http://bio.winona.msus.edu/berg/ANIMTNS/FacDiff.htm

36. Active Transport Transport of substance across a membrane against diffusion using ATP and membrane protein

37. Molecule or ion ATP = energy ATP ATP ATP ATP ATP ATP ACTIVE TRANSPORT Membrane protein

39. Cocaine blocks reuptake of dopamine Vesicle from Golgi with dopamine Neuron #2 Neuron #1 diffusion Active transport Dopamine (protein) receptor Dopamine Dopamine (protein) receptor

40. Cocaine = dopamine stimulant blocks reuptake of dopamine and leaves it synaptic cleft longer Vesicle from Golgi with dopamine Neuron #1 Neuron #2 diffusion Active transport Dopamine (protein) receptor Dopamine Dopamine (protein) receptor