Cell Boundaries Chapter 7-3. Cell Membrane Regulates what enters and leaves the cell.

Cell BoundariesChapter 7-3

Cell Membrane

Regulates what enters and leaves the cell

Diffusion • Movement of molecules from high to

low concentrations

Osmosis Movement of H2O from area of HIGH

concentration to LOW across a selectively permeable membrane

Hypotonic(“below strength”)

• Water will move INTO the cell causing it to swell

• Cells could rupture if cell takes too much water in

• Increases turgor pressure

“Hypo Hippo”

Hypertonic Solution“above strength”

• Dissolved substances are HIGHER OUTSIDE & LOWER INSIDE the cell

• H2O rushes out of the cell causing it to shrivel

Isotonic Solution“same strength”

Dissolved substances are the SAME OUTSIDE and are the SAME INSIDE

• Movement inside the cell = movement outside

PRACTICE TIME

Facilitated Diffusion• Molecules like glucose can’t just

“diffuse”, they need help by a protein channel.

• DOES NOT REQUIRE ENERGY

• HIGH to LOW

Facilitated Diffusion• High to Low

Active Transport• Requires ENERGY!!! (ATP) adenosine tri-

phosphate and protein pumps• Low concentration to High concentration

Active Transport

Active Transport

“Going Against the Gradient”

Phagocytosis“Cell Eating”

Pinocytosis“cell drinking”

Exocytosis

http://www.youtube.com/watch?v=-6cNX-DpVJw