Do Now:

1. Do Now: 1. Take papers off counter 2.Take out Egg Lab 3.Write down the homework *Facilitated Diffusion/active transport reading and questions *progress report signed *extra credit due tomorrow!!!! 5. DO NOW: Can you think of any examples in your home of molecules spreading out? Write it down on your notes!

2. Movement of Molecules Into and Out of Cells Diffusion, Passive Transport, Osmosis, and Active transport

3. Selectively Permeable Membrane: • A membrane that allows some molecules to pass through and does not allow others. • Example: A cell’s membrane is selectively permeable, it let’s some things in and out of the cell, and prevents others from coming in or out.

4. Selectively permeable…like a screen!!! What CAN go through the screen: Air Small insects? Rain What CAN’T go through the screen: Most insects Animals Kids

5. Diffusion aka Passive Transport • 1. Molecules move from areas of high concentration to area’s of low concentration • 2. Requires NO energy • It’s like going down hill

6. Examples of diffusion in the real world… • Making iced tea • Bubble bath • Air fresheners • The cramped elevator

7. Diffusion = Equilibrium HIGH concentration of molecules OUTSIDE the Cell Cell membrane LOW concentration of molecules EQUILIBRIUM!!!! INSIDE the Cell

8. AFTER BEFORE

10. What if a semi-permeable membrane does not allow the molecule to move in the direction they need to do diffusion? For example, what if the molecule is too big to fit through the holes in the membrane?

11. Osmosis: • The diffusion of water molecules • If the molecules of stuff can’t move and balance out, water goes the opposite direction to balance the concentration

12. Back to the iced tea… • You make a pitcher of iced tea by adding 2 cups of the drink mix to the pitcher of water. When you taste it, the iced tea is way too strong! But you can’t take any drink mix out of the pitcher, it is already dissolved! What should you do???

13. Here is a red blood cell. Your body is slightly salty, just like red your blood cells. Let’s see we put your red blood cells in pure water. The cell membrane though is NOT permeable. So, which way will the water go???

14. Red Blood Cells in Blood POP!!! Red Blood Cells in Pure Water

15. Now pretend we have a fresh water amoeba. It does not have a lot of salt inside its cell because it lives in fresh water. If we put the amoeba in salt water, which way would osmosis work? (remember the cell membrane is NOT permeable to salt.)

16. Amoeba shrivels up and dies Fresh Water Amoeba in Fresh Water Fresh Water Amoeba in Salt Water

17. Do Now • Take papers from side counter • Take out Egg lab- DO NOT GO TOUCH YOUR EGG • Take out the homework from two nights ago • Write down your homework: What will happen next worksheet

18. What happens when molecules can’t fit through the cell membrane, or the molecules need to move against the gradient?

19. Example: The Hamper • The laundry hamper is full, but you have your dirty clothes from soccer practice to put in there. You know you aren’t supposed to leave dirty clothes on the floor. So, you shove the clothes into the hamper, push down really hard…and phew! The lid closes! Does this take energy? Is it easy to do?

20. Active Transport • Molecules move from areas of low concentration to high (so from where there are few molecules to where there are already a lot of molecules) • This requires energy!!! (Imagine shoving molecules into someplace that is already full- it takes energy) • This is like going uphill!!!

21. Example of active transport:

22. Two ways of doing active transport: 1. Transport Proteins • Proteins in the cell membrane that work like a turnstile but force molecules in or out

24. Two ways of doing active transport: • 2. Engulfing • The cell actually moves to surround the molecule, and forms a bubble around it

26. Intro to Bio Unit 1 Active Transport 1. 2. Active Transport Example

27. Intro to Bio Unit 1 Active Transport Two ways active transport occurs 1. 2.