1. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Homeostasis and Cell Transport Chapter 5 Table of Contents Section 1 Passive Transport Section 2 Active Transport

2. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Passive Transport Chapter 5 Objectives Explain how an equilibrium is established as a result of diffusion. Distinguish between diffusion and osmosis. Explain how substances cross the cell membrane through facilitated diffusion. Explain how ion channels assist the diffusion of ions across the cell membrane.

3. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Passive Transport Chapter 5 Diffusion Passive transport involves Diffusion is the movement of molecules from an area of __________________ concentration to an area of __________________ concentration, driven by the molecules’ kinetic energy until equilibrium is reached.

4. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Diffusion Concentration Gradient – Equilibrium – Once equilibrium is reached, molecules move randomely.

5. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Passive Transport Chapter 5 Diffusion, continued Diffusion Across Membranes –Molecules can diffuse across a cell membrane by

6. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 5 Diffusion Section 1 Passive Transport

7. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Passive Transport Chapter 5 Osmosis Osmosis is the

8. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Passive Transport Chapter 5 Osmosis, continued Direction of Osmosis –The net direction of osmosis is determined by the

9. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Passive Transport Chapter 5 Osmosis, continued Direction of Osmosis –When the solute concentration outside the cell is higher than that in the cytosol, the solution outside is _________________ to the cytosol, and water will

10. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Passive Transport Chapter 5 Osmosis, continued Direction of Osmosis –When the solute concentrations outside and inside the cell are equal, the solution outside is ___________________, and there will be no net movement of water.

11. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 5 Hypertonic, Hypotonic, Isotonic Solutions Section 1 Passive Transport

12. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Passive Transport Chapter 5 Osmosis, continued How Cells Deal With Osmosis –To remain alive, cells must compensate for the water that enters the cell in hypotonic environments and leaves the cell in hypertonic environments. –Contractile vacuoles are organelles that

13. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Osmosis, continued In hypotonic solutions, water moves into plant roots and exerts pressure within the cells this is called________________________. In hypertonic solutions, water leaves the cells of plants and the cell shrinks and wilts. This condition is called_______________________.

14. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Passive Transport Chapter 5 Facilitated Diffusion In facilitated diffusion, a molecule The carrier protein then changes its shape and transports the molecule down its

15. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 5 Facilitated Diffusion Section 1 Passive Transport

16. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Passive Transport Chapter 5 Diffusion Through Ion Channels Ion channels are proteins, or groups of proteins, that provide

17. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 5 Ion Channels Section 1 Passive Transport

18. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Active Transport Chapter 5 Objectives Distinguish between passive transport and active transport. Explain how the sodium-potassium pump operates. Compare endocytosis and exocytosis.

19. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Active Transport Chapter 5 Active transport moves molecules across the cell membrane from an area of Unlike passive transport, active transport requires Cell Membrane Pumps

20. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Active Transport Chapter 5 Cell Membrane Pumps, continued Some types of active transport are performed by carrier proteins called

21. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Active Transport Chapter 5 Cell Membrane Pumps, continued Sodium-Potassium Pump –The sodium-potassium pump moves ___________ ________ ions into the cell’s external environment for every __________ __________ ions it moves into the cytosol. –___________ supplies the energy that drives the pump.

22. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 5 Sodium-Potassium Pump Section 2 Active Transport

23. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Active Transport Chapter 5 Movement in Vesicles Endocytosis –In ________________________, cells ingest external materials by folding around them and forming a pouch. –The pouch then pinches off and becomes a membrane-bound organelle called a _____________________.

24. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Active Transport Chapter 5 Movement in Vesicles, continued Endocytosis –Endocytosis includes pinocytosis, in which the –vesicle contains _________________ or –__________________, and phagocytosis, in –which the vesicle contains

25. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Active Transport Chapter 5 Movement in Vesicles, continued Exocytosis –In exocytosis, vesicles made by the cell fuse with the cell membrane,

26. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 5 Endocytosis and Exocytosis Section 2 Active Transport

27. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Passive Transport Chapter 5 Osmosis