1. 4.1 Plasma Membrane Structure and Function Regulates the entrance and exit of molecules into and out of the cell Phospholipid bilayer with embedded proteins –Hydrophilic polar heads –Hydrophobic nonpolar tails –Cholesterol (animal cells)

2. Fluid-mosaic Model of Plasma Membrane Structure

3. 4.1 Plasma Membrane Structure and Function Types of Membrane Proteins –Channel Proteins –Carrier Proteins –Cell Recognition Proteins –Receptor Proteins –Enzymatic

4. A Proteins

5. 4.2 Permeability of the Plasma Membrane Differentially (selectively) Permeable Factors that determine how a substance may be transported across a plasma membrane: –Size –Polar or Nonpolar

6. How Molecules Cross the Plasma Membrane

7. Passage of Molecules into and out of the Cell

8. 4.2 Permeability of the Plasma Membrane Diffusion and Osmosis –Diffusion is the movement of molecules from an area of higher to lower concentration

9. Process of Diffusion

10. 4.2 Permeability of the Plasma Membrane Diffusion and Osmosis –Diffusion is the movement of molecules from an area of higher to lower concentration –Oxygen and Carbon Dioxide are two gases that can diffuse through the plasma membrane

11. Gas Exchange in Lungs

12. 4.2 Permeability of the Plasma Membrane Osmosis –Osmosis is the diffusion of water across a differentially permeable membrane. –Osmotic pressure is the pressure that develops in a system due to osmosis.

13. Osmosis Demonstration

14. 4.2 Permeability of the Plasma Membrane Osmosis –Isotonic:the solute concentration is equal inside and outside of a cell

15. 4.2 Permeability of the Plasma Membrane Osmosis –Isotonic:the solute concentration is equal inside and outside of a cell –Hypotonic:a solution has a lower solute concentration than the inside of a cell

16. 4.2 Permeability of the Plasma Membrane Osmosis –Isotonic:the solute concentration is equal inside and outside of a cell –Hypotonic:a solution has a lower solute concentration than the inside of a cell –Hypertonic:a solution has a higher solute concentration than the inside of a cell

17. Osmosis in Animal and Plant Cells

18. 4.2 Permeability of the Plasma Membrane Transport by Carrier Proteins –Carrier proteins combine with a molecule or ion to be transported across the membrane.

19. 4.2 Permeability of the Plasma Membrane Transport by Carrier Proteins –Carrier proteins combine with a molecule or ion to be transported across the membrane. –Carrier proteins are required for: Facilitated Transport

20. 4.2 Permeability of the Plasma Membrane Transport by Carrier Proteins –Carrier proteins combine with a molecule or ion to be transported across the membrane. –Carrier proteins are required for: Facilitated Transport Active Transport

21. Facilitated Transport Small molecules that are not lipid-soluble Molecules combine with carrier proteins Molecules follow the concentration gradient Energy is not required

22. 4.2 Permeability of the Plasma Membrane Active Transport –Small molecules –Molecules combine with carrier proteins –Molecules move against the concentration gradient –Energy is required

23. The Sodium-Potassium Pump

24. 4.2 Permeability of the Plasma Membrane Vesicle Formation –Transport of large molecules –Requires energy –Keeps the macromolecule contained

25. 4.2 Permeability of the Plasma Membrane Vesicle Formation –Exocytosis - Vesicles form as a way to transport molecules out of a cell

26. Exocytosis

27. Vesicle Formation –Endocytosis - Vesicles form as a way to transport molecules into a cell

28. Vesicle Formation –Endocytosis - Vesicles form as a way to transport molecules into a cell Phagocytosis: Large,particulate matter

29. Vesicle Formation –Endocytosis - Vesicles form as a way to transport molecules into a cell Phagocytosis: Large,particulate matter Pinocytosis: Liquids and small particles dissolved in liquid

30. Vesicle Formation –Endocytosis - Vesicles form as a way to transport molecules into a cell Phagocytosis: Large,particulate matter Pinocytosis: Liquids and small particles dissolved in liquid Receptor Mediated Endocytosis: A type of pinocytosis that involves a coated pit

31. Three Methods of Endocytosis