1. Membranes C483 Spring 2013

2. Trans fatty acids have physical properties like those of A) w-3 fatty acids. B) cis-fatty acids. C) unsaturated fatty acids. D) saturated fatty acids. Triacylglycerols are not found in cell membranes because they are A) amphipathic. B) not amphipathic. C) not abundant in cells. D) charged at biological pH. Glycerophospholipids have ________ heads and long ________ fatty acid tails. A) polar; polar B) polar; hydrophobic C) hydrophobic; polar D) hydrophobic; hydrophobic

3. Which type of membrane protein might be dissociated from the membrane by changing the pH or the ionic strength? A) Integral membrane protein. B) Lipid-anchored membrane protein. C) Peripheral membrane protein. D) All of the above. Which can serve as an energy source for secondary active transport? A) Ion concentration gradient. B) Light. C) Electron transport. D) ATP → ADP

4. Lipids and Membranes There is a lot of important biochemistry of lipids. We won’t cover it all! The key points for this class have to do with their role in membranes and fat metabolism

5. Overview Read chapter 9, sections 1-4, 6, 8-10 – Section 9.11 is important in discussion Major topics – Metabolism: fatty acids and triacylglyderieds – Membrane components: phosphoglycerides and steroids – Membrane structure and dynamics – Membrane function: transport

6. Diversity

7. Fatty Acids Saturated Unsaturated Polyunsaturated Cis and trans

8. Triacylglyderides

9. Phosphoglycerides aka glycerophospholipids Polar head, hydrophobic tail

10. Diversity

11. Phospholipases Wide variety of phosphoglycerides Processed by range of lipases Snake venom

12. Steroids Structural similarity, functional diversity

13. Membranes Complex Fluid Dynamic Compartment- alization Communication Gradients

14. Lipid Bilayer

15. Dynamic

16. Fluid Mosaic Glycoproteins, proteins Affect of cholesterol

17. Integral Membrane Proteins

18. Lipid anchored membrane proteins

19. Membrane Transport No thermodynamics for now Pores and channels Selective permeability Sets up gradients

20. Types of Transport Passive Transport—with concentration or charge gradient – Diffusion across membrane – Facilitated diffusion Active Transport—goes against concentration or charge gradient – Requires energy input – Always facilitated

21. Facilitated Transport

22. Types of Transport Both passive and active transport can be – Uniport – Symport – Antiport

23. Primary and Secondary Transport

24. Answers 1.D 2.B 3.B 4.C 5.A