3. Cell Membrane Structure Lipid bi-layer Proteins imbedded as channels for transfers

4. Selective Permeability  Property of cell membrane  Allows some substances in/out  Cells need nutrients/oxygen in  Cells need carbon dioxide/wastes out

5.  Particles of matter in constant motion.  Solid particles move less than liquids & gases.  Particles move from crowded areas to less crowded areas until equilibrium is reached (evenly dispersed) Background Information

6. - net movement of molecules from areas of HIGH concentration to LOW concentration Diffusion Definition

7. Diffusion Example Diffusion of perfume in a classroom! The Diffusion Applet

8. Facilitated Diffusion  Carrier protein : molecules in cell membrane that “help” substances move in/out of cell  Specific protein for each molecule  Type of Passive Transport  Used for: –Molecules too large for fluid membrane –Molecules not soluble in lipid bilayer animation

9. Osmosis Osmosis: Osmosis: movement of water across cell membrane from high concentration to area of lower concentration -AKA the diffusion of water.

10. Osmosis: Diffusion of Water

11. “ Solution ” for your Transport Solution is: –A solute dissolved in a solvent Solvent is : –Generally is water in living systems Solute is: –Glucose, oxygen, salt etc; that which is dissolved in the solvent WHAT IS THE SOLVENT AND WHAT IS THE SOLUTE WHEN YOU MAKE JELLO???

12. What is concentration? Mass of solute in a given volume. (example: g/L) –30 grams of solute in 2 liters of water: 30 g/ 2 L OR 15 g/L Which of the three has the greatest concentration? –30 grams of sugar in 5 L of water –20 grams of sugar in 40 L of water –50 grams of sugar in 25 L of water?

13. Concentration Gradient The difference in the concentration of molecules across a space. Molecules are said to move down a concentration gradient.

14. What happened here? Draw a sketch of the solutions:

15. Hyper vs. Hypo Hypertonic – The solution with a higher concentration of solute in it. Hypotonic – The solution with a lower concentration of solute in it. Isotonic – solutions which have equal concentrations of solute.

16. Direction of Osmosis Isotonic : Cell and environment have equal concentration of solute Hypotonic: Cell has a lower concentration of solute than the environment Hypertonic : Environment has higher concentration of solute than the cell 20% salt 80% salt

17. Plasmolysis O Shrinkage cytoplasm inside the cell membrane O Due to the loss of water from a plant cell O Causes plants to wilt - Loss of inside cell pressure: Turgor Pressure

18. Dealing With Osmosis Contractile Vacuoles (protozoa) –Pumps excess water out Plasmolysis (plant cells) –Water loss; turgor pressure drops Cytolysis (animal cells) –High turgor pressure; cell explodes

20. Passive Transport  movement down concentration gradient  cells do not use energy; - particles move by kinetic energy  includes: diffusion, osmosis, facilitated diffusion

21. Active Transport - Movement from LOW concentration to HIGH concentration (UP concentration gradient!) - Cells use energy (ATP) Example: plant roots pull in minerals from soil

22. Active v.s. Passive Transport

23. Endocytosis - Cell membrane: o surrounds a substance o pinches off o forms a vesicle o brings substance IN -Includes: o Phagocytosis o Pinocytosis

24. Phagocytosis 1 2 3 Phagocytosis

25. Exocytosis Vesicle contents are released at the cell membrane

26. Application of Diffusion / Osmosis Dialysis o Kidney job: filter wastes from your blood o Damaged kidney  hook patient up to dialysis - Blood is run from body to dialysis machine - Machine filters out wastes by diffusion. - Cleansed blood is returned to the body

27. Kidneys

28. Fish Gill Function This is a close-up of a thin channel in the fish's gills. Water flows through it and is surrounded by blood vessels, that flow in opposite direction. The oxygen leaves the water, and goes into the blood. From there, it is carried all around the body of the fish!