1. Cell Membrane Movement

2. _____ tends to diffuse from an area of ____ water concentration to an area of _____ water concentration.

3. Comparing solutions A __________ solution is a solution in which the concentration of dissolved substances is _________ than the concentration inside the cell. If a cell is placed in a hypertonic solution, osmosis will make the water _____ the cell and the cell will shrink.

4. A _______ solution is a solution in which the concentration of dissolved substances is _______ than the concentration inside the cell. If a cell is placed in a hypotonic solution, osmosis will cause water to move through the plasma membrane _____ the cell and the cell will burst. Comparing solutions

5. An ______ solution is a solution in which the concentration of dissolved substances is the _____ as the concentration inside the cell. Psst! Remember “equilibrium”?

6. Osmotic Pressure Osmosis exerts a pressure known as ________ _________ on the hypertonic side of a selectively permeable membrane.

7. Because the cell is filled with salts, sugars, proteins, and other molecules, it will almost always be _________ to fresh _______. If so, the osmotic pressure should produce a net _________ of water into the cell. As a result, the volume of the cell will _________ until the cell becomes swollen or bursts. Osmotic Pressure

8. Osmosis Cells in _______ organisms are not in danger of bursting because they are bathed in fluids, such as blood, that are _______. Other cells are surrounded by tough cell walls that prevent the cells from expanding even under tremendous osmotic pressure.

9. Facilitated Diffusion _____ ________ have protein channels that act as carriers, making it easy for _______ molecules to cross.

10. Facilitated Diffusion The movement of specific molecules across cell membranes through protein channels is known as _______ _______. Hundreds of different protein channels have been found that allow particular __________ to cross different membranes.

11. Facilitated Diffusion Protein channel Glucose molecules

12. Facilitated Diffusion Although _________ diffusion is fast and specific, it is still diffusion. Therefore, facilitated diffusion will only occur if there is a ______ concentration of the particular molecules on one side of a cell membrane as compared to the other side.

13. Active Transport Sometimes ______ move materials in the ________ direction from which the materials would normally move—that is against a concentration difference. This process is known as ______ _______. Active transport requires energy.

14. Active Transport Molecular Transport * In active transport, _____ molecules and ions are carried across membranes by proteins in the membrane. * Energy use in these systems enables cells to _________ substances in a particular _______, even when diffusion might move them in the opposite direction.

15. Active Transport Molecule to be carried This transports particles _______ a concentration difference. This forced movement requires energy.

16. Active Transport Endocytosis and Exocytosis – ______ molecules and even ______ clumps of material may undergo active transport through the ____ ________. – ____________ is the process of taking material into the cell by means of infoldings, or pockets of the cell membrane. – The pocket breaks loose from the outer portion of the cell membrane and forms a _______ within the cytoplasm.

17. Two examples of endocytosis are phagocytosis and pinocytosis. In __________, extensions of cytoplasm surround a particle and package it within a food vacuole. The cell then engulfs it. Phagocytosis requires a considerable amount of ______.

18. In _________, tiny pockets form along the cell membrane, fill with _______, and pinch off to form vacuoles within the cell. Two examples of endocytosis are phagocytosis and pinocytosis.

19. Active Transport Exocytosis – Many cells also release ______ amounts of material from the cell, in a process called ________. – During _________, the membrane of the vacuole surrounding the material fuses with the ____ _______, forcing the contents out of the cell.

20. End of Membrane movement notes Any questions?