Empowering Teachers Through Modeling

Transcription

1 Empowering Teachers Through Modeling Many Models of Membranes! WORKSHOP LEARNING OBJECTIVES Educators attending this workshop will: o Utilize tools that can support the NGSS student learning outcomes of three dimensional lesson design. o Phospholipid Modeling Set o Phospholipid and Membrane Transport Kit o The Landscapes of David Goodsell o 3D Printed Models o Learn something new and interesting that is for your own professional development. o HAVE FUN! WORKSHOP LEARNING OBJECTIVES What NGSS dimensions will be targeted? SEPs CCCs DCIs Asking questions Patterns PS1.A: Structure and Developing and using models Constructing explanations Cause and effect Scale, proportion, and quantity Structure and function properties of matter PS1.B: Chemical reactions LS1.A: Structure and function LS1.C: Organization for matter and energy flow in organisms 1

2 Examine the phospholipid molymod at your table. Record your observations and answers to each of the following: 1. Describe the overall structure of your model. 2. What atoms are present in your model and what color represents each of these atoms? 3. What other observations or questions do you have about your model? 4. Compare and contrast your group s phospholipid to another group s phospholipid. 5. Make note of any similarities. 6. Make note of any differences. 7. Speculate why a cell membrane would have different phospholipids. The Outer Leaflet Phosphatidylcholine Sphingomyelin The Inner Leaflet Phosphatidylethanolamine Phosphatidylserine Phosphatidylinositol 2

3 GOALS of Developing and Using Models Construct drawings or diagrams as representations of events or systems. Represent and explain phenomena with multiple types of models. Hydrogens in the cis configuration Produces a larger kink in the tail Hydrogens in the trans configuration Produces a smaller kink in the tail 3

4 Step 1: Remove one of the hydrogen (H) atoms from the glycerol. Step 3: Combine the H and the OH to form water. Step 2: Remove the hydroxyl (OH) group from the fatty acid. Step 4: Remove one of the hydrogen (H) atoms from the glycerol. Step 5: Repeat the process with the unsaturated fatty acid. 4

5 Step 6: Remove the final H from the glycerol and the OH from the phospholipid head. Combine the H and the OH. Find the phospholipid head to the glycerol backbone. A Series of Gedanken Experiments! First Thought Experiment: How would ten phospholipids need to be arranged to form a film at the top of a beaker of water? A Series of Gedanken Experiments! Second Thought Experiment: How would the ten phospholipids need to be arranged in order to be submerged in a beaker of water? 5

6 A Series of Gedanken Experiments! Third Thought Experiment: How would the phospholipids need to be arranged if they were to be submerged AND contain water? (You may use as many phospholipids as needed in the kit.) How does a polar molecule, like water, diffuse through a largely hydrophobic bilayer? It gets by with a little help from its friend... AQUAPORIN! 6

7 2003 NOBEL PRIZE IN CHEMISTRY -For discoveries concerning channels in cell membranes Peter Agre - for the discovery of aquaporins, proteins that govern the movement of water in and out of cells NOBEL PRIZE IN CHEMISTRY -For discoveries concerning channels in cell membranes Roderick MacKinnon - for structural and mechanistic studies of ion channels. HOW WAS AQUAPORIN DISCOVERED? Exploding Frog Eggs! Postdoctorate Fellow, Gregory Preston This is what experimental success jubilation looks like! 7

8 Observe and count the helices! What happens to the orientation of the water molecules as they pass through the channel? Find the two asparagines. The models are to scale and magnified 20 million times their actual size! 8

9 Explore other channels! GLUT Carrier Protein Gated Potassium Channel Aquaporin Potassium Leak Channel Sodium-Potassium Pump Use the GLUT Carrier Protein to model passive transport with a carrier protein. Use the Sodium-Potassium Pump to model active transport! 9