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Team “Insane in the Membrane”. Team members: Heather Addy , Anna Davis, Cindy Graham, Joan Marshall, Vesal Mahanian. Membrane Structure and Function. 26 July 2012. Learning Goals. Understand why phospholipids spontaneously arrange into micelles and vesicles when mixed in water
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Team “Insane in the Membrane” Team members: Heather Addy, Anna Davis, Cindy Graham, Joan Marshall, Vesal Mahanian
Membrane Structure and Function 26 July 2012
Learning Goals • Understand why phospholipids spontaneously arrange into micelles and vesicles when mixed in water • Identify the properties/structure of phospholipid bilayers make them selectively permeable. • Collaborate with others to solve a problem • Learn to communicate and defend a scientific argument based on experimental evidence
After this session you will be able to… • Predict (and draw) the arrangements of phospholipids in an aqueous solution, based on their chemical properties • Deduce the properties that govern membrane permeability of molecules from experimental data • Evaluate whether different compounds can diffuse across a simple lipid bilayer based on polarity, size and charge.
Foundations • Previously we learned about the… • Importance of intermolecular forces • Relationship between polarity and hydrophobicity • How functional groups influence the chemical properties of molecules • Properties of water
Oil and water don’t mix Oleic Acid (Lipid) Water
Properties of Phospholipids If we mix phospholipids in water, how will they organize? In a group of 3, draw at least 2 arrangements of phospholipid molecules in water... 2 minutes
Phospholipids spontaneously form micelles and bilayers in water • Fatty acid chains aggregate together • Phosphate-containing head groups associate with water
What properties determine whether a molecule crosses a phospholipid bilayer?
Small Group Activity • In a recent experiment, the permeability coefficient of various molecules was determined • Organize the molecules in order of permeability and consider what structural/chemical features contribute to their permeability 5 minutes
Which can pass through a membrane more readily? Why? Summative Assessment: #1 #2
Which can pass through a membrane more readily? Why? Summative Assessment: Answer #1 Vitamin B2: Water soluble, cannot pass through a phospholipid bilayer because it’s large and polar #1 #2 Vitamin E: Fat soluble, is able to pass through the phospholipid bilayer because it’s non-polar (looks like a fat) #2
Small Group Activity Cards Progesterone P=3.5x10E-4 cm/s O=O Oxygen P=42 cm/s
Acetate P=1x10E-12 cm/s Acetic acid P=2x10E-2 cm/s Glycerol P=5x10E-5 cm/s Na+ Sodium ion P=1x10E-12 cm/s Water P=5x10E-2 cm/s Glucose P=2x10E-7 cm/s