1. Notes on Chapter 6.2 & 6.3 Movement through the Membrane

2. Homeostasis Examples:Examples: Body temperatureBody temperature SweatingSweating ShiveringShivering DehydrationDehydration Over-hydrationOver-hydration Definition: Process by which organisms maintain a relatively stable internal environment

3. A. Definitions 1. Semi-permeable: allows only certain substances to pass allows only certain substances to pass Ex: cell membranes and nuclear Ex: cell membranes and nuclear membranes membranes 2. Permeable: allows all substances to pass through through II. SEMI/SELECTIVELY PERMEABLE MEMBRANE

4. 3. Impermeable: no substances can 3. Impermeable: no substances can pass through pass through B.Live cell membranes are semi-permeable semi-permeable

5. D. Cell membrane Function Regulates the substances that enter and leave the cellRegulates the substances that enter and leave the cell

6. D. Cell Membrane Functions Con. ’ t A barrierA barrier ProtectionProtection SupportSupport CommunicationCommunication

7. Lipid bilayer consists of: phospholipids These are the Parts that Make Up Cell Membranes Bilayer = Double layerBilayer = Double layer ‘Head’: hydrophilic‘Head’: hydrophilic ‘Tails’: hydrophobic‘Tails’: hydrophobic

8. III. Passive Transport A. Definition: Movement of molecules into and out of cell Movement of molecules into and out of cell that requires no energy that requires no energy B. Why?: Molecules are always in random motion! Molecules are always in random motion! Will always move from area of high Will always move from area of high concentration to low concentration to low

9. C. Types of passive transport:

10. 1. Diffusion a. Movement of ANYTHING from high concentration to low concentration »Does not require energy! Examples:Examples: Food coloringFood coloring Tea bagTea bag PopcornPopcorn PerfumePerfume

12. 2. Osmosis- Water Only! a. Definition: - Special kind of diffusion of water over - Special kind of diffusion of water over selectively permeable membrane selectively permeable membrane - From high concentration to low - From high concentration to low concentration concentration

13. b. Examples:

14. Isotonic 97% H 2 O Diagram Where is the most water? Which way does water go? Result? Big words Examples 97% H 2 O Same Inside and outside Even, same concentration overall “dynamic equilibrium” “homeostasis contact lens solution,

15. Hypotonic Diagram Where is the most water? Which way does water go? Result? Big words Examples 92% H 2 O 97% H 2 O Outside Inside Burst, get bigger; firm “plasmoptysis”- to burst; “turgid”- get firm; “turgor pressure” :pressure inside plant cells to help stand upright Distilled water

16. Paramecium

17. Hypertonic Diagram Where is the most water? Which way does water go? Result? Big words Examples 97% H 2 O 80% H 2 O Inside Outside Smaller, shrink, go limp “plasmolysis”- to wilt, shrivel, loss of pressure “flaccid”- go limp Candy, sugar, salt on bushes/grass, gargle with salt water

18. Hypertonic

19. 3. Facilitated Diffusion a.Definition: Uses proteins in cell membrane to escort larger molecules across, from area of high concentration to low. b. Ex: » Alcohol, H 2 O, small lipids » Allows in bigger molecules » No energy required!

21. IV. Active transport A. Definition: movement of molecules across a membrane requiring energy; movement of molecules across a membrane requiring energy; from LOW to HIGH concentration! from LOW to HIGH concentration! B.Types Endocytosis- materials come into cell Exocytosis- materials leave cell

25. V. Concentration Gradient Explanation: Explanation: measurement of how the concentration of measurement of how the concentration of something changes from one place to another something changes from one place to another A. Passive Transport: molecules go DOWN concentration gradient from molecules go DOWN concentration gradient from HIGH to LOW concentration HIGH to LOW concentration B. Active Transport: molecule go UP concentration gradient from LOW molecule go UP concentration gradient from LOW to HIGH concentration to HIGH concentration