CELL TRANSPORT MODULE ASHLEY J. TAYLOR MVHS Science Department M V H S CELL MEMBRANE A semi-permeable barrier made up of a double layer of phospholipids that monitors the passage of materials in and out of the cell. Source: Nowicki, S. (2008). Chapter 3: Cells. In McDougal Littell Biology (pp. 82). Evanston, IL: McDougal Littell MOVEMENT ACROSS MEMBRANE Important Terms • Concentration is the number of molecules of a substance in a given volume. • Concentration gradient is the difference in the concentration of a substance from one location to another. Materials move across membranes because of concentration differences. PASSIVE TRANSPORT Passive transport is the movement of molecules across the membrane from areas of higher concentration to areas of lower concentration. It does not require energy input from the cell. Three Types of Passive Transport Diffusion Osmosis Facilitated Diffusion TYPES OF PASSIVE TRANSPORT Diffusion movement of molecules from areas of higher concentration to areas of lower concentration Osmosis movement from high to low movement of water from areas of higher concentration to areas of lower concentration Movement of molecules across a membrane through transport proteins Facilitated Diffusion PASSIVE TRANSPORT ANIMATIONS ACTIVE TRANSPORT Active Transport occurs when a cell uses energy to move molecules against a concentration gradient. Molecules are moved from lower to higher concentration. It does require energy input from the cell. Types of Active Transport Endocytosis Exocytosis SodiumPotassium Pump TYPES OF ACTIVE TRANSPORT Endocytosis Exocytosis “Cell Eating” the opposite of endocytosis removal of substances out of a cell by the fusion of a vesicle with the membrane. cell membrane engulfs a substance and brings it inside the cell ENERGY REQUIRED LOW - HIGH Sodium-Potassium Pump Movement of Na+ and K+ ions across a membrane through the use of a pump. Requires Energy in the form of ATP & a Carrier Protein ACTIVE TRANSPORT ANIMATIONS UNDERSTANDING CHECK Na+ K+ Pump Energy Required Source: Shuster, et al., Biology for a Changing World, First Edition, W. H. Freeman & Co. © 2012 W. H. Freeman & Co. and Sumanas, Inc. REINFORCEMENT ACTIVITY Cell Transport Puzzles Please complete the following Cell Transport Puzzles Double clicking on the puzzle will open the PDF file and allow printing. Puzzles generated and provided by USATest Prep SOURCES Nowicki, S. (2008). Chapter 3: Cells. In McDougal Littell Biology (pp. 70-84). Evanston, IL: McDougal Littell Shuster, et al., Biology for a Changing World, First Edition, W. H. Freeman & Co. © 2012 W. H. Freeman & Co. and Sumanas, Inc.