Remember!

1. Remember! • Osmosis is the movement of water across a semi-permeable membrane! • Until there is an equal amount of free water molecules on each side!

2. Osmosis in Cells

3. Isotonic Solution • The same concentration of solute on both sides of the membrane • Water will continue to move into & out of the cell at an even rate! If there’s an equal concentration of sugar inside & outside of the cell, the cell won’t gain or lose any water.

4. Hypotonic Solution • Outside solution has a lower concentration of solute than inside the cell (higher concentration of free water outside the cell) • Water will move into the cell! These red blood cells are in a hypotonic solution & have gained water!

5. Hypertonic Solution • Outside solution has a higher concentration of solute than inside the cell (lower concentration of water outside the cell) • Water will move out of the cell! These red blood cells are in a hypertonic solution & have lost water!

6. Isotonic Hypertonic Hypotonic

7. Click on Image to watch video

8. Click on image to watch video

9. Click on image to watch video

10. What causes plants to wilt? When plants don’t get enough water, they wilt! Without water, the plant cells will begin to shrink & shrivel. Would this be an example of isotonic, hypotonic, or hypertonic?

11. Facilitated & Active Transport

12. Video Facilitated Diffusion • Movement of a molecule across a membrane when protein channels are required • Sometimes, molecules are too big to pass or they are charged & can’t pass through the membrane without help! • When a protein channel helps a molecule pass, this is called facilitated diffusion! • Protein channels are specific for 1 type of molecule!

13. Active Transport • Movement of molecules from low concentration to high concentration • The opposite of diffusion! • Types of Active Transport: • Molecular • Endocytosis • Exocytosis

14. Molecular Transport • Used for small ions (calcium, potassium, sodium, etc.) • Must pump ions across the membrane – this requires energy! • Involves changes in protein shape

15. Endocytosis • For transport of larger molecules into the cell • Occurs with pockets of the cell membrane that fold into the cells, creating a vacuole that is released into the cytoplasm • A vacuole is a bubble-shaped part of the cell used for storage.

16. 2 Types of Endocytosis – Phagocytosis & Pinocytosis • Phagocytosis: “cell eating” – cell takes up particles & forms a food vacuole

17. 2 Types of Endocytosis – Phagocytosis & Pinocytosis • Pinocytosis: “cell drinking” – cell takes up liquid from the surrounding environment

18. Exocytosis • Release of materials from the cell