1. Cell Membranes and transport of Materials

2. Do Now: Shipwrecked
A shipwrecked sailor is stranded on a small desert island with no fresh water to drink. She knows she could last without food for up to a month, but if she didn’t have water to drink she would be dead within a week. Hoping to postpone the inevitable, her thirst drove her to drink the salty water. She was dead in two days. Why do you think drinking the saltwater killed her faster than not drinking any water at all?

3. Introduction

4. The Cell Membrane

5. Plasma Membrane (aka Cell Membrane)
Phosopholipid Bilayer
Called the Fluid Mosaic Model
Selectively Permeable

6. Selectively Permeable
If a membrane is selectively permeable only certain things can pass through

7. Selectively Permeable
Only certain materials can go in and out of the cell

8. The Cell Membrane is Selective:
Things that passively cross:
Non-Polar Molecules (O2 & Co2)
Small Molecules (Water)
Things that actively cross:
Polar Molecules (Na+, K+, Cl-)
Large Molecules (glucose, starch)

9. Types of Transport
Passive
(no ATP)
Active
(requires ATP)

10. Passive Transport
Passive
Diffusion
Osmosis
Facilitated
Diffusion

11. Movement of materials that DOES NOT require energy (ATP)
Passive Transport
Movement of materials that DOES NOT require energy (ATP)

12. What is happening here???

13. DIFFUSION
The passive movement of material from an area of high concentration to an area of low concentration

14. The number of a substance in a specific area
Concentration
The number of a substance in a specific area

15. High Concentration
Low Concentration

16. High Concentration
Passive Transport
Low Concentration

18. Factors Affecting Diffusion
Concentration—diffusion always goes from high concentration to low concetration
Temperature—the higher the temperature, the faster diffusion occurs
Molecular Size—the bigger the molecule, the longer diffusion takes

19. The diffusion of water through a selectively permeable membrane
OSMOSIS
The diffusion of water through a selectively permeable membrane

21. Osmosis—another look…

22. No net movement of water in or out of the cell
Isotonic Solution
No net movement of water in or out of the cell

23. Hypotonic Solution
Water moves from the solution into the cell causing it to swell or break (lysis)

24. Hypertonic Solution
The water moves out of the cell into the solution, causing the cell to shrink

25. Types of Solutions

26. Why doesn’t the plant cell shrivel up?

27. Explain what is happening in this cartoon…

28. Procedures
Your teacher has cut three potato pieces for your group; measure and record the diameter of each potato core.
Using the balance, measure and record the mass of each potato core.

29. 3. Place one potato core in the cup with solution A and label this cup “Solution A". Place the second core in the cup with Solution B and label the cup “Solution B". Place the third core in the cup with solution C and label this cup “Solution C".
4. Cover the top of each cup with a piece of aluminum foil. Fold the aluminum foil down along the sides of the cup so that it cannot fall off easily.
5. Allow the cups to sit for a day.  STOP HERE

30. Lab – Diffusion & Osmosis
Cover Page: title, picture, name/date/section
Title – “The effects of IV on DV?
Intro – Use all key terms in intro
Diffusion - Osmosis
Selectively permeable - Passive transport
Concentration
Problem – “What are the effects…?”
Hypothesis – Leave ~ 5 lines…
Data:

31. COVER PAGE Create a cover page for today’s lab
Title: Diffusion and Osmosis
Name, Date, Period
Picture

32. Intro
In this lab we will study osmosis by ______________. Osmosis is movement of water from a region of _____ water concentration to a region of _______ water concentration. Diffusion, on the other hand, is movement _________. The potato has a ______-_________ membrane, so it only lets certain things through. The ____ in the water will be too big to pass through the ___________, so water will either enter or exit the cell to reach _____________.

33. Hypothesis
If the potato swells, then the water moved (in/out), so the solution had (more/less) sugar than the potato. This would mean the solution is (isotonic/hypertonic/hypotonic) to the potato.

34. Data Solution A Solution B Solution C Day 1 Day 2 Change Length Mass
Appearance

35. Facilitated Diffusion
Diffusion that is helped by proteins in the membrane

36. Facillitated Diffusion

37. Diffusion vs. Facillitated Diffusion

38. Active Transport Active Pumps Membrane Movements Endocytosis
Exyocytosis

39. Active Transport
Movement of materials from low concentration to high concentration using a protein carrier that requires energy (costs ATP)

40. High Concentration
Active Transport
Low Concentration