Cellular Transport Section 7.3 How cells move or transport the stuff they want into the cell & get the stuff they don’t want out! Page 208 – “Think About It” 2 Types of Transport • Passive Transport – We will talk about this type of transport first! – Requires no energy. – 3 Types: diffusion, osmosis, & facilitated diffusion • Active Transport – Requires Energy – 3 Types: Pumps, Endocytosis, Exocytosis Diffusion • Definition: movement of molecules from an area of high concentration to low concentration • What is concentration? • Concentration is an amount. • Example: What does it mean if a pool has a high concentration of chlorine? • Why? – molecules in constant motion, collide, & spread – More molecules, higher probability to collide • When all molecules are equally spread apart this is called Equilibrium Membrane Function The Cell Membrane regulates what enters & exits the cell! Maintains Homeostasis! Serves as a selective barrier meaning the membrane “selects” what it will allow to enter or exit the cell semi-permeable membrane! How would the glucose move? 1M glucose 0.1M glucose 0.55M glucose 0.55M glucose Types of Diffusion • Special Case Osmosis • Definition = diffusion of water Concentration Gradient • Definition = a difference in concentration across an area • High Low = – down the gradient • Low High = – up the gradient How does osmosis apply to cells? • Q: What would happen if we put a cell in pure water? What would happen if we put a cell in salt water? Shrink Osmosis in Living Cells Cellulose in cell wall Label the solutions below.