Name:_____________________ Skittle/Peanut M&M Pump Materials: 2 popsicle stick fences 1 paper mache box 1 clear plastic ball 20 skittles and 20 peanut M&Ms 3 small paper clips (same color) 1 big paper clip 1 oval wooden frame (optional) Activity: We need your help! A very important cell that is vital to the survival of mankind has broken down. We have discovered that a mechanism called the sodium potassium pump is not working properly. Your mission, if you choose to accept it is to be shrunk down to the microscopic level and infiltrate the cell. Once inside the cell, you and your partner must manually activate the pump. You are our last hope and the fate of mankind is in your hands! This message will self-destruct in 5 seconds……. Procedure: 1) Facing your partner, set up your plasma membrane model so it is on the desk 2) 3) 4) 5) in front of each of you. Assign one partner to sit inside the cell and the other to sit outside the cell. *Be clear on who is sitting where. Labels such as “In” and “Out” are recommended If you are sitting inside the cell take 16 M&Ms and 6 skittles and place them on your side of the membrane. If you are sitting outside the cell take 14 skittles and 4 M&Ms and place them on your side of the membrane. Now you are ready to work the pump! First, we begin with the person sitting inside the cell. He/she is to pick up 3 skittles which represent 3 sodium ions, and place them inside the pump. Now that the pump is filled with sodium, the pump needs energy in order to release the ions outside of the cell. This energy comes from Adenosine Triphosphate (ATP). The person who is sitting inside the cell should pick up an ATP (paper clip chain) and attach it to the pump. Once the ATP is attached, only one phosphate group should remain attached to the pump. This means the rest of the molecule should become ADP and be set aside. * At this point, the pump should have 3 Sodium molecules inside, and also have a phosphate group attached (1 small paperclip). 6) The person sitting outside the cell can now open the pump and remove the sodium ions. Once the sodium ions are outside the cell, they can be replaced with 2 peanut M&Ms which represent potassium ions. 7) The person sitting inside the cell will then remove the potassium ions from the pump, and release them inside the cell. Also they need to remove the phosphate from the pump. 8) Repeat the process until you know the steps by heart. Also be sure to switch positions, so each partner has a chance to be inside the cell. Questions: 1) How does active transport differ from diffusion, facilitated diffusion, and osmosis? 2) Explain what a concentration gradient is, and why it is important in respect to the sodium potassium pump? How was a gradient shown in the activity? 3) How could you rearrange your model/candy in order to demonstrate passive transport? 4) What type of macromolecule forms the sodium/potassium pump? Where does the energy come from to power this pump? 5) What characteristics of the plasma membrane make the sodium potassium pump a necessity for cells to function properly?