Transcript File
CELLULAR TRANSPORT! CELLULAR TRANSPORT Passive vs. Active Passive cellular transport: No energy (ATP) Required A. Diffusion-moves gases across the membrane from high to low! – Oxygen, carbon dioxide, and fume particles B. Osmosis – movement of water from high to low • • • Isotonic : no net movement Hypotonic: water in Hypertonic: water out – Remember “SALT SUCKS!!” Isotonic Solution 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) • 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 Hypotonic Solution 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! Osmosis in Elodea cells 2: isotonic + tap water Notice the chloroplasts are evenly spaced 1: Elodea + pure water Notice the chloroplast at the edge of the cell wall 3: Elodea + salt Notice all chloroplasts in the center; membrane pulled away from cell wall Cell wall chloroplasts membrane vacuole C. Facilitated Diffusion • The movement of particles from areas of HIGH concentrations to areas of LOW concentration with the HELP of a TRANSPORT protein. Like regular diffusion, this is a type of PASSIVE transport and does NOT require energy! • Animation: How Facilitated Diffusion Works D. Active Transport • Movement of particles AGAINST the concentration gradient from areas of LOW to areas of HIGH concentration. This does require ENERGY!! • Example: Ion Pump • http://www.brookscole.com/chemistry_d/temp lates/student_resources/shared_resources/ani mations/ion_pump/ionpump.html E. BULK transport…when molecules are too BIG to pass… • 1. ENDOCYTOSIS: movement of a substance INTO the cell – Phagocytosis (food in) – Pinocytosis (fluid in) PHAGOCYTOSIS • Watch this animation!! • http://www.stolaf.edu/people/giannini/flasha nimat/cellstructures/phagocitosis.swf • Amoeba Horror!!! PINOCYTOSIS • Watch this animation – • Endocytosis - Animation of Pinocytosis 2. EXOCYTOSIS • Movement of a substance OUT of the cell • http://www.emc.maricopa.edu/faculty/farabe e/BIOBK/exocyt.gif