Movement Through the Cell Membrane Cell Membrane The
Movement Through the Cell Membrane
Cell Membrane • The thin flexible barrier around the cell that regulates what enters and leaves. • Selectively permeable- some substances can pass and others cannot
Cell membrane is made up of: • Lipid bilayer- two layers of • Carbohydrates- act as chemical identification fat (Fence) cards (NAME TAGS) for cells to identify one Protein channels- that move another. (Security) materials across. (Gates)
Diffusion (Passive Transport) • The movement of molecules from an area of high concentration to an area of low concentration. • Does not require energy! • Equilibrium (Think equal)-When concentration of molecules inside/outside cell is about equal.
Facilitated Diffusion (Passive Transport) • When molecules are too large to pass through membrane lipids • carrier proteins (protein channels) help move molecules from high to low concentration • No cell energy used.
Diffusion Animation • http: //www. phschool. com/atschool/phbio/a ctive_art/diffusion/index. html
Osmosis (passive transport) • Diffusion of water across a selectively permeable membrane. • Does not require energy
Osmosis Animation • http: //www. phschool. com/atschool/phbio/a ctive_art/osmosis/index. html
Active Transport (uses cell energy) • Endocytosis-(think enter) -when cells ingest materials too big to pass through the membrane (macromolecules, large particles, other cells). – EX: phagocytosis
Active Transport (cont. ) • Exocytosis-(think exit)- substances removed from cell by vesicles – Remove: proteins, toxins, waste products
Active Transports • http: //www. phschool. com/atschool/phbio/a ctive_art/active_transport/index. html
Hypotonic Solution • Osmosis Animations for isotonic, hypertonic, and hypotonic solutions Hypotonic: The solution has a lower concentration of solutes and a higher concentration of water than inside the cell. (Low solute; High water) Result: Water moves from the solution to inside the cell): Cell Swells and bursts open (cytolysis)!
Hypertonic Solution • Osmosis Animations for isotonic, hypertonic, and hypotonic solutions Hypertonic: The solution has a higher concentration of solutes and a lower concentration of water than inside the cell. (High solute; Low water) shrinks Result: Water moves from inside the cell into the solution: Cell shrinks (Plasmolysis)!
• Isotonic Solution Osmosis Animations for isotonic, hypertonic, and hypotonic solutions Isotonic: The concentration of solutes in the solution is equal to the concentration of solutes inside the cell. Result: Water moves equally in both directions and the cell remains same size! (Dynamic Equilibrium)
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