Cellular Transport 7.4

Diffusion Baking cookies aroma Baking cookies aroma Particles in G, L, S are in constant motion Particles in G, L, S are in constant motion Brownian motion  substances dissolved in water moving constantly in random motion Brownian motion  substances dissolved in water moving constantly in random motion Diffusion  caused by random motion. Diffusion  caused by random motion. Net movement of particles from high concentration to low concentration Net movement of particles from high concentration to low concentration Moving from a high concentration to a low concentration require no energy (passive transport) Moving from a high concentration to a low concentration require no energy (passive transport)

Demo Red and Blue mix (a result of diffusion) to create a purple color Red and Blue mix (a result of diffusion) to create a purple color Eventually the colors will have become fully mixed. Even though there is movement there will not be a change in concentration. (dynamic equilibrium achieved) Eventually the colors will have become fully mixed. Even though there is movement there will not be a change in concentration. (dynamic equilibrium achieved)

Rate of Diffusion Three factors affect the rate of diffusion Three factors affect the rate of diffusion Temperature Temperature Concentration Concentration Pressure Pressure When any of those 3 increase…So does Diffusion When any of those 3 increase…So does Diffusion

Facilitated Diffusion Transport Proteins move ions and small molecules (Na+ or glucose) across the plasma membrane Transport Proteins move ions and small molecules (Na+ or glucose) across the plasma membrane

Osmosis The diffusion of water across a selective permeable membrane The diffusion of water across a selective permeable membrane Water will move across the membrane to balance the concentration on either side Water will move across the membrane to balance the concentration on either side

Isotonic Solution A cell that is in a solution of the same concentration of water and solutes as the cells cytoplasm, the cell is an isotonic solution A cell that is in a solution of the same concentration of water and solutes as the cells cytoplasm, the cell is an isotonic solution Iso  Equal Iso  Equal There is no net movement of water There is no net movement of water

Hypotonic Solution A cell in a solution of lower concentration of solute A cell in a solution of lower concentration of solute There is more Water outside the cell than inside There is more Water outside the cell than inside Hypo  Under Hypo  Under Net movement of water is into the cell Net movement of water is into the cell

Hypertonic Solution The concentration of the solute outside of the cell is higher than inside The concentration of the solute outside of the cell is higher than inside There is more water inside the cell than outside There is more water inside the cell than outside Hyper  Above Hyper  Above Net movement of water is out of the cell Net movement of water is out of the cell

Active Transport Moving from a region of LOW concentration to a region with a HIGH concentration Moving from a region of LOW concentration to a region with a HIGH concentration Active transport  Moving against the concentration gradient. It requires energy. Active transport  Moving against the concentration gradient. It requires energy. Accomplished by Pump proteins Accomplished by Pump proteins

Sodium-Potassium ATPase pump Common Active Transport Pump Common Active Transport Pump Pump found in plasma membrane of animals Pump found in plasma membrane of animals Moves 3 sodium ions out of the cell against the concentration gradient Moves 3 sodium ions out of the cell against the concentration gradient

Transporting Large Particles Endocytosis  process by allowing a large particle outside the cell to enter the cell Endocytosis  process by allowing a large particle outside the cell to enter the cell Plasma membrane dimples and pinches around the particle allowing it to enter without destroying the membrane Plasma membrane dimples and pinches around the particle allowing it to enter without destroying the membrane Process results in a vacuole or vesicle Process results in a vacuole or vesicle

Exocytosis Secretion of materials at the plasma membrane Secretion of materials at the plasma membrane The reverse of Endocytosis The reverse of Endocytosis

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